| ID |
Date |
Author |
Type |
Category |
Subject |
|
55
|
Fri Jan 18 13:25:17 2013 |
Koji | Optics | Configuration | Autocollimator calibration | An autocollimator (AC) should show (0,0) if a retroreflector is placed in front of the AC.
However, the AC may have an offset. Also the retroreflector may not reflect the beam back with an exact parallelism.
To calibrate these two errors, the autocollimator is calibrated. The retroreflector was rotated by 0, 90, 180, 270 deg
while the reticle position are monitored. The images of the autocollimator were taken by my digital camera looking at the eyepiece of the AC.
Note that 1 div of the AC image corresponds to 1arcmin.
Basically the rotation of the retroreflector changed the vertical and horizontal positions of the reticle pattern by 0.6mdeg and 0.1mdeg
(2 and 0.4 arcsec). Therefore the parallelism of the retrorefrector is determined to be less than an arcsec. This is negligibly good for our purpose.
The offset changes by ~1div in a slanted direction if the knob of the AC, whose function is unknown, is touched.
So the knob should be locked, and the offset should be recorded before we start the actual work every time. |
|
56
|
Sat Jan 19 20:47:41 2013 |
Koji | Optics | Characterization | Wedge measurement with the autocollimator | The wedge angle of the prism "A1" was measured with the autocollimator (AC).
The range of the AC is 40 arcmin. This means that the mirror tilt of 40arcmin can be measured with this AC.
This is just barely enough to detect the front side reflection and the back side reflection.
The measured wedge angle of the A1 prism was 0.478 deg.
Ideally a null measurement should be done with a rotation stage. |
|
57
|
Tue Jan 22 11:10:25 2013 |
Koji | Facility | General | Eyeware storage and hooks for the face shields are installed | A carpenter has come to install the eyeware storage and hooks for the face shields. |
|
58
|
Tue Jan 22 17:56:32 2013 |
Koji | Mechanics | General | Rotary stage selection | Newport UTR80
Newport 481-A (SELECTED)
- Sensitivity: 15 arcsec
- Graduations: 1 deg
- Vernier: 5 arcmin
- Fine travel range: 5 deg
- With Micrometer
Newport RS40
- Sensitivity: 16 arcsec
- Graduations: 2 deg
- Vernier: 12 arcmin
- Fine travel range: 10 deg
- Micrometer BM11.5
Newport RS65
- Sensitivity: 11 arcsec
- Graduations: 2 deg
- Vernier: 12 arcmin
- Fine travel range: 10 deg
- Micrometer SM-06 to be bought separately
Elliot science MDE282-20G
- Sensitivity: 5 arcsec
- Graduations: 2 deg
- Vernier: 10 arcmin
- Fine travel range: 10 deg
- Micrometer 2 arcmin/1div
- Metric
Suruga precision B43-110N
Thorlabs precision B43-110N
|
|
59
|
Mon Feb 4 00:39:08 2013 |
Koji | Optics | Characterization | Wedge measurement with the autocollimator and the rotation stage | Method:
- Mount the tombstone prism on the prism mount. The mount is fixed on the rotation stage.
- Locate the prism in front of the autocollimator.
- Find the retroreflected reticle in the view. Adjust the focus if necessary.
- Confirm that the rotation of the stage does not change the height of the reticle in the view.
If it does, rotate the AC around its axis to realize it.
This is to match the horizontal reticle to the rotation plane.
- Use the rotation stage and the alignment knobs to find the reticle at the center of the AC.
Make sure the reticle corresponds to the front surface.
- Record the micrometer reading.
- Rotate the micrometer of the rotation stage until the retroreflected reticle for the back surface.
- There maybe the vertical shift of the reticle due to the vertical wedging. Record the vertical shi
- Record the micrometer reading. Take a difference from the previous value.
Measurement:
- A1: α = 0.68 deg, β = 0 arcmin (0 div)
- A2: α = 0.80 deg, β = -6 arcmin (3 div down)
- A3: α = 0.635 deg, β = -1.6 arcmin (0.8 div down)
- A4: α = 0.650 deg, β = 0 arcmin (0div)
- A5: α = 0.655 deg, β = +2.4 arcmin (1.2 div up)
Analysis:
- \theta_H = ArcSin[Sin(α) / n]
- \theta_V = ArcSin[Sin(β) / n]/2
- A1: \theta_H = 0.465 deg, \theta_V = 0.000 deg
- A2: \theta_H = 0.547 deg, \theta_V = -0.034 deg
- A3: \theta_H = 0.434 deg, \theta_V = -0.009 deg
- A4: \theta_H = 0.445 deg, \theta_V = 0.000 deg
- A5: \theta_H = 0.448 deg, \theta_V = 0.014 deg
|
|
60
|
Wed Feb 6 02:34:10 2013 |
Koji | Optics | Characterization | Wedge measurement with the autocollimator and the rotation stage | Measurement:
- A6: α = 0.665 deg, β = +3.0 arcmin (1.5 div up)
- A7: α = 0.635 deg, β = 0.0 arcmin (0.0 div up)
- A8: α = 0.623 deg, β = - 0.4 arcmin (-0.2 div up)
- A9: α = 0.670 deg, β = +2.4 arcmin (1.2 div up)
- A10: α = 0.605 deg, β = +0.4 arcmin (0.2 div up)
- A11: α = 0.640 deg, β = +0.8 arcmin (0.4 div up)
- A12: α = 0.625 deg, β = - 0.6 arcmin (-0.3 div up)
- A13: α = 0.630 deg, β = +2.2 arcmin (1.1 div up)
- A14: α = 0.678 deg, β = 0.0 arcmin (0.0 div up)
- B1: α = 0.665 deg, β = +0.6 arcmin (0.3 div up)
- B2: α = 0.615 deg, β = +0.2 arcmin (0.1 div up)
- B3: α = 0.620 deg, β = +0.9 arcmin (0.45 div up)
- B4: α = 0.595 deg, β = +2.4 arcmin (1.2 div up)
- B5: α = 0.635 deg, β = - 1.8 arcmin (-0.9 div up)
- B6: α = 0.640 deg, β = +1.6 arcmin (0.8 div up)
- B7: α = 0.655 deg, β = +2.5 arcmin (1.25 div up)
- B8: α = 0.630 deg, β = +2.8 arcmin (1.4 div up)
- B9: α = 0.620 deg, β = - 4.0 arcmin (-2.0 div up)
- B10: α = 0.620 deg, β = +1.2 arcmin (0.6 div up)
- B11: α = 0.675 deg, β = +3.5 arcmin (1.75 div up)
- B12: α = 0.640 deg, β = +0.2 arcmin (0.1 div up)
Analysis:
- \theta_H = ArcSin[Sin(α) * n]
- \theta_V = ArcSin[Sin(β) / n]/2
- A6: \theta_H = 0.490 deg, \theta_V = 0.017 deg
- A7: \theta_H = 0.534 deg, \theta_V = 0.000 deg
- A8: \theta_H = 0.551 deg, \theta_V = -0.0023 deg
- A9: \theta_H = 0.482 deg, \theta_V = 0.014 deg
- A10: \theta_H = 0.577 deg, \theta_V = 0.0023 deg
- A11: \theta_H = 0.526 deg, \theta_V = 0.0046 deg
- A12: \theta_H = 0.548 deg, \theta_V = -0.0034 deg
- A13: \theta_H = 0.541 deg, \theta_V = 0.013 deg
- A14: \theta_H = 0.471 deg, \theta_V = 0.000 deg
- B1: \theta_H = 0.490 deg, \theta_V = 0.0034 deg
- B2: \theta_H = 0.563 deg, \theta_V = 0.0011 deg
- B3: \theta_H = 0.556 deg, \theta_V = 0.0051 deg
- B4: \theta_H = 0.592 deg, \theta_V = 0.014 deg
- B5: \theta_H = 0.534 deg, \theta_V = -0.010 deg
- B6: \theta_H = 0.526 deg, \theta_V = 0.0091 deg
- B7: \theta_H = 0.504 deg, \theta_V = 0.014 deg
- B8: \theta_H = 0.541 deg, \theta_V = 0.016 deg
- B9: \theta_H = 0.556 deg, \theta_V = -0.023 deg
- B10: \theta_H = 0.556 deg, \theta_V = 0.0068 deg
- B11: \theta_H = 0.475 deg, \theta_V = 0.020 deg
- B12: \theta_H = 0.526 deg, \theta_V = 0.0011 deg
| Quote: |
|
Measurement:
- A1: α = 0.68 deg, β = 0 arcmin (0 div)
- A2: α = 0.80 deg, β = -6 arcmin (3 div down)
- A3: α = 0.635 deg, β = -1.6 arcmin (0.8 div down)
- A4: α = 0.650 deg, β = 0 arcmin (0div)
- A5: α = 0.655 deg, β = +2.4 arcmin (1.2 div up)
Analysis:
- \theta_H = ArcSin[Sin(α)*n]
- \theta_V = ArcSin[Sin(β) / n]/2
- A1: \theta_H = 0.465 deg, \theta_V = 0.000 deg
- A2: \theta_H = 0.547 deg, \theta_V = -0.034 deg
- A3: \theta_H = 0.434 deg, \theta_V = -0.009 deg
- A4: \theta_H = 0.445 deg, \theta_V = 0.000 deg
- A5: \theta_H = 0.448 deg, \theta_V = 0.014 deg
|
|
|
61
|
Thu Feb 7 21:35:46 2013 |
Koji | General | General | Dmass's loan of LB1005 / A2&C2 sent to Fullerton / First Contact @40m | Dmass borrowed the LB1005 servo amp from the OMC lab.
It happened this week although it seems still January in his head. Got it back on Mar 24th
The A2 and C2 mirrors have been sent to Josh Smith at Fullerton for the scatterometer measurement.
First Contact kit (incl. Peek Sheets)
Manasa borrowed the kit on Feb 7. Got it back to the lab.
|
|
62
|
Thu Feb 7 23:01:45 2013 |
Koji | Optics | Characterization | UV epoxy gluing test | [Jeff, Yuta, Koji]
Gluing test with UV-cure epoxy Optocast 3553-LV-UTF-HM
- This glue was bought in the end of October (~3.5 months ago).
- The glue was taken out from the freezer at 1:20pm.
- Al sheet was laid on the optical table. We made a boat with Al foil and pour the glue in it (@1:57pm)
- We brought two kinds of Cu wires from the 40m. The thicker one has the diameter of 1.62mm.
The thinner one has the diameter of 0.62mm. We decided to use thinner one being cut into 50mm in length.
- The OMC glass prisms have the footprint of 10mmx20mm = 200mm^2. We tested several combinations
of the substrates. Pairs of mirrors with 1/2" mm in dia. (127mm) and a pair of mirrors with 20mm in dia. (314mm).
- Firstly, a pair of 1/2" mirrors made of SF2 glass was used. A small dub on a thinner Cu wire was deposited on a mirror.
We illuminated the glue for ~10sec. When the surfaces of the pair was matched, the glue did not spread on the entire
surface. The glue was entirely spread once the pressure is applied by a finger. Glue was cured at 2:15pm. 12.873mm
thickness after the gluing.
Some remark:
1. We should be careful not to shine the glue pot by the UV illuminator.
2. The gluing surface should be drag wiped to remove dusts on the surface.
- Secondly, we moved onto 20mm mirror pair taken from the remnant of the previous gluing test by the eLIGO people.
This time about 1.5 times more glue was applied.
- The third trial is to insert small piece of alminum foil to form a wedge. The thickness of the foil is 0.041mm.
The glue was applied to the pair of SF2 mirror (1/2" in dia.). A small dub (~1mm in dia) of the glue was applied.
The glue filled the wedge without any bubble although the glue tried to slide out the foil piece from the wedge.
So the handling was a bit difficult. After the gluing we measured the thickness of the wedge by a micrometer gauge.
The skinny side was 12.837mm, and the thicker side was 12.885mm. This is to be compared with the total thickness
12.823mm before the gluing. The wedge angle is 3.8mrad (0.22deg). The glue dub was applied at 2:43, and the UV
illumination was applied at 2:46.
- At the end we glued a pair of fused silica mirrors. The total thickness before the gluing was 12.658 mm.
The glue was applied at 2:59pm. The thickness after the gluing is 12.663 mm.
This indicates the glue thickess is 5um.
|
|
63
|
Thu Feb 21 18:44:18 2013 |
Koji | Optics | Configuration | Perpendicularity test | Perpendicularity test of the mounting prisms:
The perpendicularity of the prism pieces were measured with an autocollimator.
Two orthogonally jointed surfaces forms a part of a corner cube.
The deviation of the reflected image from retroreflection is the quantity measured by the device.
When the image is retroreflected, only one horizontal line is observed in the view.
If there is any deviation from the retroreflection, this horizontal line splits into two
as the upper and lower halves have the angled wavefront by 4x\theta. (see attached figure)
The actual reading of the autocollimator is half of the wavefront angle (as it assumes the optical lever).
Therefore the reading of the AC times 30 gives us the deviation from 90deg in the unit of arcsec.
SN / measured / spec
SN10: 12.0 arcsec (29 arcsec)
SN11: 6.6 arcsec (16 arcsec)
SN16: 5.7 arcsec (5 arcsec)
SN20: -17.7 arcsec (5 arcsec)
SN21: - 71.3 arcsec (15 arcsec)
|
|
64
|
Wed Feb 27 18:18:48 2013 |
Koji | Optics | Configuration | More perpendicularity test | Mounting Prisms:
(criteria: 30arcsec = 145urad => 0.36mm spot shift)
SN Meas.(div) ArcSec Spec.
10 0.3989 11.97 29 good
11 0.2202 6.60 16 good
16 0.1907 5.72 5 good
20 -0.591 -17.73 5 good
21 -2.378 -71.34 15
21 -1.7 -51. 15
01 -0.5 -15. 52
02 -2.5 -75. 48
06 -1.0 -30. 15 good
07 1.7 51. 59
12 -2.2 -66. 40
13 -0.3 - 9. 12 good
14 -2.8 -84. 27
15 -2.5 -75. 50
17 0.7 21. 48
22 2.9 87. 63
Mirror A:
A1 -0.5 -15. NA good
good
A4 0.9 27. NA good
A5 0.4 12. NA good
A6 0.1 3. NA good
A7 0.0 0. NA good
A8 0.0 0. NA good
A9 0.0 0. NA good
A10 1.0 30. NA good
A11 0.3 9. NA good
A12 0.1 3. NA good
A13 0.0 0. NA good
A14 0.6 18. NA good
Mirror B:
B1 -0.9 -27. NA good
B2 -0.6 -18. NA good
B3 -0.9 -27. NA good
B4 0.7 21. NA good
B5 -1.1 -33. NA
B6 -0.6 -18. NA good
B7 -1.8 -54. NA
B8 -1.1 -33. NA
B9 1.8 54. NA
B10 1.2 36. NA
B11 -1.7 -51. NA
B12 1.1 33. NA
|
|
65
|
Fri Mar 1 23:06:15 2013 |
Koji | Optics | Configuration | More perpendicularity test final | Perpendicularity of the "E" mirror was measured.
Mounting Prisms:
(criteria: 30arcsec = 145urad => 0.36mm spot shift)
SN Meas.(div) ArcSec Spec.
10 0.3989 11.97 29 good
11 0.2202 6.60 16 good
16 0.1907 5.72 5 good
20 -0.591 -17.73 5 good
21 -2.378 -71.34 15
21 -1.7 -51. 15
01 -0.5 -15. 52
02 -2.5 -75. 48
06 -1.0 -30. 15 good
07 1.7 51. 59
12 -2.2 -66. 40
13 -0.3 - 9. 12 good
14 -2.8 -84. 27
15 -2.5 -75. 50
17 0.7 21. 48
22 2.9 87. 63
Mirror A:
A1 -0.5 -15. NA good
good
A4 0.9 27. NA good
A5 0.4 12. NA good
A6 0.1 3. NA good
A7 0.0 0. NA good
A8 0.0 0. NA good
A9 0.0 0. NA good
A10 1.0 30. NA good
A11 0.3 9. NA good
A12 0.1 3. NA good
A13 0.0 0. NA good
A14 0.6 18. NA good
Mirror B:
B1 -0.9 -27. NA good
B2 -0.6 -18. NA good
B3 -0.9 -27. NA good
B4 0.7 21. NA good
B5 -1.1 -33. NA
B6 -0.6 -18. NA good
B7 -1.8 -54. NA
B8 -1.1 -33. NA
B9 1.8 54. NA
B10 1.2 36. NA
B11 -1.7 -51. NA
B12 1.1 33. NA
Mirror E:
E1 -0.8 -24. NA good
NA good
E3 -0.25 - 7.5 NA good
E4 -0.5 -15. NA good
E5 0.8 24. NA good
good
good
good
E14 -1.0 -30. NA good
good
good
|
|
66
|
Fri Mar 1 23:52:18 2013 |
Koji | Optics | Characterization | Wedge measurement with the autocollimator and the rotation stage | Measurement:
- E1: α = 0.672 deg, β = +0.0 arcmin (0 div up)
- E2: α = 0.631 deg, β = - 0.3 arcmin (-0.15 div down)
- E3: α = 0.642 deg, β = +0.0 arcmin (0 div up)
- E4: α = 0.659 deg, β = +1.4 arcmin (0.7 div up)
- E5: α = 0.695 deg, β = +0.5 arcmin (0.5 div up)
- E6: α = 0.665 deg, β = - 0.4 arcmin (-0.2 div down)
- E7: α = 0.652 deg, β = +1.0 arcmin (0.5 div up)
- E8: α = 0.675 deg, β = +2.0 arcmin (1.0 div up)
- E9: α = 0.645 deg, β = - 2.4 arcmin (-1.2 div down)
- E10: α = 0.640 deg, β = +2.2 arcmin (1.1 div up)
- E11: α = 0.638 deg, β = +1.6 arcmin (0.8 div up)
- E12: α = 0.660 deg, β = +1.6 arcmin (0.8 div up)
- E13: α = 0.638 deg, β = +0.8 arcmin (0.4 div up)
- E14: α = 0.655 deg, β = +0.4 arcmin (0.2 div up)
- E15: α = 0.640 deg, β = +1.4 arcmin (0.7 div up)
- E16: α = 0.655 deg, β = +0.6 arcmin (0.3 div up)
- E17: α = 0.650 deg, β = +0.8 arcmin (0.4 div up)
- E18: α = 0.640 deg, β = +2.4 arcmin (1.2 div up)
Analysis:
- \theta_H = ArcSin[Sin(α) / n]
- \theta_V = ArcSin[Sin(β) / n]/2
- E1: \theta_H = 0.460 deg, \theta_V = 0.000 deg
- E2: \theta_H = 0.432 deg, \theta_V = -0.0034 deg
- E3: \theta_H = 0.439 deg, \theta_V = 0.000 deg
- E4: \theta_H = 0.451 deg, \theta_V = 0.016 deg
- E5: \theta_H = 0.475 deg, \theta_V = 0.011 deg
- E6: \theta_H = 0.455 deg, \theta_V = -0.0046 deg
- E7: \theta_H = 0.446 deg, \theta_V = 0.011 deg
- E8: \theta_H = 0.462 deg, \theta_V = 0.023 deg
- E9: \theta_H = 0.441 deg, \theta_V = -0.027 deg
- E10: \theta_H = 0.438 deg, \theta_V = 0.025 deg
- E11: \theta_H = 0.436 deg, \theta_V = 0.018 deg
- E12: \theta_H = 0.451 deg, \theta_V = 0.018 deg
- E13: \theta_H = 0.436 deg, \theta_V = 0.0091 deg
- E14: \theta_H = 0.448 deg, \theta_V = 0.0046 deg
- E15: \theta_H = 0.438 deg, \theta_V = 0.016 deg
- E16: \theta_H = 0.448 deg, \theta_V = 0.0068 deg
- E17: \theta_H = 0.444 deg, \theta_V = 0.0091 deg
- E18: \theta_H = 0.438 deg, \theta_V = 0.027 deg
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69
|
Thu Mar 7 15:53:47 2013 |
Koji | Mechanics | General | OMC Transportation fixture, OMC PD/QPD mounts | 
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70
|
Thu Mar 14 17:06:21 2013 |
Koji | Mechanics | General | OMC SUS work @LLO | EDIT (ZK): All photos on Picasa. Also, I discovered that since Picasa was migrated to Google+ only,
you no longer have the option to embed a slideshow like you used to. Lame, Google.
Photos sent from Zach
(3D VIEW)
 
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71
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Thu Mar 14 22:18:23 2013 |
Koji | General | General | New loans for the diode test | ALL returned
Loan from ATF:
2 blue banana cables returned on Jun 4, 2013
BNC cable returned on Mar 21, 2013
TENMA triple power supply returned on July 17, 2015
From 40m:
4x GPIB cables returned on Mar 21, 2013
From EE shop:
red banana cables returned on Jun 4, 2013
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72
|
Fri Mar 15 02:15:45 2013 |
Koji | Electronics | Characterization | Diode testing | Diode testing
o Purpose of the measurement
- Test Si QPDs (C30845EH) for ISC QPDs Qty 30 (i.e. 120 elements)
- Test InGaAs PDs (C30665GH) for OMC Qty 10 (i.e. 10 elements)
o Measurement Kit
- Inherited from Frank.
- Has relays in it.
- D0 and D1 switches the measurement instrument connected to an element
- D2 and D3 switches the element of the QPDs
- Digital switch summary
d0 d1 0 0 - ln preamp
d0 d1 1 0 - dark c
d0 d1 0 1 - omc preamp
d0 d1 1 1 - impedance
d2 d3 0 0 - A x x x
d2 d3 1 0 - C x o x
d2 d3 0 1 - B o x o
d2 d3 1 1 - D o o o
- The universal board in the box is currently configured for C30845.
Pin1 - Elem A. Pin3 - B, Pin7 - C, Pin9 - D, Pin 12 - Case&Bias
o Labview interface
- Controls NI-USB-6009 USB DAQ interface and Agilent 82357B USB-GPIB interface
o Dark current measurement
- Borrowed Peter's source meter KEITHLEY 2635A
- For C30845GH the maxmum reverse bias is set to -20V. This drops the voltage of the each element to the bias voltage.
o Spectrum measurement
- The elements are connected to FEMTO LN current amp DLPCA-200.
- Bias voltage is set to +10V. This lifts up the outside of the amplifier input to +10V.
o Impedance measurement
- Agilent 4395A at PSL lab with impedance measurement kit
- For C30845GH the maxmum reverse bias is set to -15V. This drops the voltage of the each element to the bias voltage.
- Calibration: open - unplug the diode from the socket, short - use a piece of resister lead, 50Ohm - a thin metal resister 51Ohm
- Freq range: 30-50MHz where the response of the cables in the setup is mostly flat.
- Labview VI is configured to read the equivalent circuit parameters in the configuration "D" (series LCR).
- Labview fails to read the series resistance. This was solved by first read the equiv circuit param and then read it with Sim F-CHRST.
F-CHRST does nothing on the parameters so the second request successfully acquires the first ones.
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73
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Sun Mar 17 21:59:47 2013 |
Koji | Electronics | Characterization | Diode testing ~ DCPD | - For the dark noise measurement, the lid of the die-cast case should also contact to the box for better shielding. This made the 60Hz lines almost completely removed, although unknown 1kHz harmonics remains.
- The precise impedance of the setup can not be obtained from the measurement box; the cable in between is too long. The diode impedance should be measured with the impedance measurement kit.
- With the impedance measurement kit, the bias voltage of +5V should be used, in stead of -5V.
- diode characteristics measured at 10-100MHz
- Typical impedance characteristics of the diodes
Excelitas (Perkin-Elmer) C30665GH Rs=9Ohm, Cd=220pF, L=0~1nH (Vr=5V)
Excelitas (Perkin-Elmer) C30642G Rs=12Ohm, Cd=100pF, L=~5nH (Vr=5V) longer thin wire in a can?
Excelitas (Perkin-Elmer) C30641GH Rs=8Ohm, Cd=26pF, L=12nH (Vr=5V) leg inductance? (leg ~30mm)
- PD serial
C30665GH, Ls ~ 1nH
1 - 0782 from PK, Rs=8.3Ohm, Cd=219.9pF
2 - 1139 from PK, Rs=9.9Ohm, Cd=214.3pF
3 - 0793 from PK, Rs=8.5Ohm, Cd=212.8pF
4 - 0732 from PK, Rs=7.4Ohm, Cd=214.1pF
5 - 0791 from PK, Rs=8.4Ohm, Cd=209.9pF
6 - 0792 from PK, Rs=8.0Ohm, Cd=219.0pF
7 - 0787 from PK, Rs=9.0Ohm, Cd=197.1pF
8 - 0790 from PK, Rs=8.4Ohm, Cd=213.1pF
9 - 0781 from PK, Rs=8.2Ohm, Cd=216.9pF
10 - 0784 from PK, Rs=8.2Ohm, Cd=220.0pF
11 - 1213 from the 40m, Rs=10.0Ohm, Cd=212.9pF
12 - 1208 from the 40m, Rs=9.9Ohm, Cd=216.8pF
13 - 1209 from the 40m, Rs=10.0Ohm, Cd=217.5pF
C30642G, Ls ~ 12nH
20 - 2484 from the 40m EG&G, Rs=12.0Ohm, Cd=99.1pF
21 - 2487 from the 40m EG&G, Rs=14.2Ohm, Cd=109.1pF
22 - 2475 from the 40m EG&G glass crack, Rs=13.5Ohm, Cd=91.6pF
23 - 6367 from the 40m ?, Rs=9.99Ohm, Cd=134.7pF
24 - 1559 from the 40m Perkin-Elmer GH, Rs=8.37Ohm, Cd=94.5pF
25 - 1564 from the 40m Perkin-Elmer GH, Rs=7.73Ohm, Cd=94.5pF
26 - 1565 from the 40m Perkin-Elmer GH, Rs=8.22Ohm, Cd=95.6pF
27 - 1566 from the 40m Perkin-Elmer GH, Rs=8.25Ohm, Cd=94.9pF
28 - 1568 from the 40m Perkin-Elmer GH, Rs=7.83Ohm, Cd=94.9pF
29 - 1575 from the 40m Perkin-Elmer GH, Rs=8.32Ohm, Cd=100.5pF
C30641GH, Perkin Elmer, Ls ~ 12nH
30 - 8983 from the 40m Perkin-Elmer, Rs=8.19Ohm, Cd=25.8pF
31 - 8984 from the 40m Perkin-Elmer, Rs=8.39Ohm, Cd=25.7pF
32 - 8985 from the 40m Perkin-Elmer, Rs=8.60Ohm, Cd=25.2pF
33 - 8996 from the 40m Perkin-Elmer, Rs=8.02Ohm, Cd=25.7pF
34 - 8997 from the 40m Perkin-Elmer, Rs=8.35Ohm, Cd=25.8pF
35 - 8998 from the 40m Perkin-Elmer, Rs=7.89Ohm, Cd=25.5pF
36 - 9000 from the 40m Perkin-Elmer, Rs=8.17Ohm, Cd=25.7pF
Note:
1mm Au wire with dia. 10um -> 1nH, 0.3 Ohm
20mm BeCu wire with dia. 460um -> 18nH, 0.01 Ohm |
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75
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Sat Mar 23 02:32:23 2013 |
Koji | Facility | General | N2 cylinder delivered | Preparation for ionized N2 blow
- 99.9998% N2 cylinder delivered (ALPHAGAZ 2 grade by AIR LIQUIDE) ALPHAGAZ 2 [PDF]
- Filter and Arcing module already in the lab
- A brass regulator to be installed (Done - March 24)
- 50 ft air line already in the lab / needs to be wiped/rinsed (Done - March 24)
- Air line and filter installed (Done - March 24) |
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76
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Sat Mar 23 02:41:00 2013 |
Koji | Optics | General | Black glass beam dumps for the first OMC | Received black glass beam dumps from MIT
- gluing by EP30-2 looks pretty fine. Enough sturdy.
- some gap visible between the glass => incident angle should be considered so that the first beam does not exit from the gap
- Dusts are visible on the glass surface. Some have a lot, the other have less. But every piece still needs to be wiped. |
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77
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Sat Mar 23 13:34:14 2013 |
Koji | Optics | General | PZT assembly prototype glued |
Prototype PZT assembly
Motivation:
Before we glue the PZT assembly, we need to build a prototype. This is to confirm the heat cure process
does not cause any cracking of the PZT or glass components. The CTE of the PZT is 2~3ppm
(depends on the direction) while the one for Fused Silica is 0.55ppm.
Materials:
- A fused silica substrate, 1/2" in dia. Supplied from Garilynn. I defined the chamfered side as the front side.
- PZT: Noliac NAC2124, serial #24, this is a spare PZT as this has the worst length to angle coupling.
- Mounting Prism: D1102069 SN22. This has the worst perpendicularity among the prisms.
- Fixtures:
D1300185 aLIGO OMC CURVED MIRROR BONDING FIXTURE ASSY
D1300186 aLIGO OMC CURVED MIRROR BONDING FIXTURE FRONT
D1300187 aLIGO OMC CURVED MIRROR BONDING FIXTURE BACK
D1300188 aLIGO OMC CURVED MIRROR BONDING FIXTURE RING
Procedure:
- Wipe all of the components with the isopropanol.
- Attach the back piece of the fixture on the Al wrapped bracket.
(The current 4-40 screws for the middle piece are too long and stick out from the back side of the back piece.
Therefore a 1/16" shim for a 1/2" rod is inserted between the bracket and the back piece)
- Brought a glue package to the lab (10:40PM)
- Loosely attach the middle piece to the back piece with four 4-40 screws.
- Insert the mounting prism in the fixture. Insert the PZT in the fixture too.
- Insert a dummy substrate in the fixture.
- Attach the front piece with spring loaded screws.
- Align the PZT and the optic in the fixture. (Basically apply downward force to them)
- Test the rigidity of the assembly (11:30PM)
- Remove the PZT and the mirror. Apply UV epoxy.
(A single dub was applied for each PZT surface of the PZT but this was too much.)
- Make sure the PZT and the optic are aligned by applying the downward force.
- Illuminate UV light from the front.
- Illuminate UV light from the back. (11:50PM)
Procedural issues:
- Long 4-40 screws (described above)
(Circumvented)
- As the PZT is not constrained with the middle piece, it tends to move vertically and rotationally
because of the wire tension. (This is not a mistake but the design so that the PZT is constrained by the optic.)
Therefore after applying glue on the PZT, the motion of the PZT spreads the glue on the back surface of
the curved mirror.
(Solution to be tried) Our solution is to glue the PZT and the mounting prism first with a dummy optics (made of SF2).
The wires should be tacked somewhere on the mount
- The amount of glue on the PZT was too much. I gave one dub of glue for each side.
As a result, excess glue leaks out along the ring.
- The front plate has a chamfered hole but this tends to slip and move the mirror vertically.
Later I used the flat side of the plate to hole the mirror.
(Circumvented) It seems that this hold the mirror in a better way as the plate can't rock
- Spring load for the front plate was too strong. This was because the natural length of the spring was too long.
(Circumvented) The spring was cut at the length of the 4-40 screw. Then attaching the screws became completely fine.
Result:
 
Slide show:
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78
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Sat Mar 23 16:36:15 2013 |
Koji | Electronics | Characterization | Diode QE measurement | Quantum efficiencies of the C30665GH diodes were measured.
- The diode was biased by the FEMTO preamplifier.
- Diode Pin 1 Signal, Pin 2 +5V, Pin 3 open
- Preamp gain 10^3 V/A
- Beam power was measured by the thorlabs power meter.
PD #1
Incident: 12.82 +/- 0.02 mW
Vout: 9.161 +/- 0.0005 V
PD Reflection (Prompt): 0.404 mW
PD Reflection (Total): 1.168 mW
PD #2
Incident: 12.73 +/- 0.02 mW
Vout: 9.457 +/- 0.0005 V
PD Reflection (Prompt): 0.364 mW
PD Reflection (Total): 0.937 mW
PD #3
Incident: 12.67 +/- 0.02 mW
Vout: 9.1139 +/- 0.01 V
PD Reflection (Prompt): 0.383 mW
PD Reflection (Total): 1.272 mW
PD #4
Incident: 12.71 +/- 0.02 mW
Vout: 9.3065 +/- 0.0005 V
PD Reflection (Prompt): 0.393 mW
PD Reflection (Total): 1.033 mW
PD #5
Incident: 12.69 +/- 0.02 mW
Vout: 9.1071 +/- 0.005 V
PD Reflection (Prompt): 0.401 mW
PD Reflection (Total): 1.183 mW
PD #6
Incident: 12.65 +/- 0.02 mW
Vout: 9.0310 +/- 0.01 V
PD Reflection (Prompt): 0.395 mW
PD Reflection (Total): 1.306 mW
PD #7
Incident: 12.67 +/- 0.02 mW
Vout: 9.0590 +/- 0.0005 V
PD Reflection (Prompt): 0.411 mW
PD Reflection (Total): 1.376 mW
PD #8
Incident: 12.63 +/- 0.01 mW
Vout: 9.0790 +/- 0.0005 V
PD Reflection (Prompt): 0.420 mW
PD Reflection (Total): 1.295 mW
PD #9
Incident: 12.67 +/- 0.02 mW
Vout: 9.2075 +/- 0.0005 V
PD Reflection (Prompt): 0.384 mW
PD Reflection (Total): 1.091 mW
PD #10
Incident: 12.70 +/- 0.01 mW
Vout: 9.0880 +/- 0.001 V
PD Reflection (Prompt): 0.414 mW
PD Reflection (Total): 1.304 mW
PD #11
Incident: 12.64 +/- 0.01 mW
Vout: 9.2861 +/- 0.0005 V
PD Reflection (Prompt): 0.416 mW
PD Reflection (Total): 1.152 mW
PD #12
Incident: 12.68 +/- 0.02 mW
Vout: 9.3650 +/- 0.001 V
PD Reflection (Prompt): 0.419 mW
PD Reflection (Total): 1.057 mW
PD #13
Incident: 12.89 +/- 0.01 mW
Vout: 9.3861 +/- 0.001 V
PD Reflection (Prompt): 0.410 mW
PD Reflection (Total): 1.047 mW
PD serial number
1 - 0782
2 - 1139
3 - 0793
4 - 0732
5 - 0791
6 - 0792
7 - 0787
8 - 0790
9 - 0781
10 - 0784
11 - 1213
12 - 1208
13 - 1209
{
{1, 12.82, 9.161, 0.404, 1.168},
{2, 12.73 , 9.457, 0.364 , 0.937} ,
{3, 12.67 , 9.1139, 0.383 , 1.272 },
{4, 12.71 , 9.3065, 0.393 , 1.033 },
{5, 12.69, 9.1071, 0.401 , 1.183 },
{6, 12.65, 9.0310, 0.395 , 1.306} ,
{7, 12.67, 9.0590, 0.411 , 1.376} ,
{8, 12.63 , 9.0790, 0.420 , 1.295} ,
{9, 12.67 , 9.2075, 0.384 , 1.091} ,
{10, 12.70, 9.0880, 0.414 , 1.304 },
{11, 12.64 , 9.2861, 0.416 , 1.152} ,
{12, 12.68 , 9.3650, 0.419 , 1.057} ,
{13, 12.89 , 9.3861, 0.410 , 1.047}
};
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79
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Mon Mar 25 02:04:05 2013 |
Koji | General | General | OMC building plan / procedure ~ WB18 | WB 18 March
- Diode test
- Dark current / Dark noise / Impedance
- Quantum Efficiency test (but with glass)
- Diode given to Bob for cleaning
- Research possible issue of UV light on 1064 HR coating
- ~ppm order loss increase after depositing 3J/cm^2 in 8 hours (i.e. same order to our illumination but in 10s for us)
- Sent an e-mail to Ke-Xun Sun -> So far, no reply.
- Glue test of PZT+prism+curved mirror with UV bond epoxy
- Done. Found some handling issues on the fixture.
- Preparation of N2 line:
Action items:
- Bake test at 100°C for 1 hour at CIT
- Will be done on 25 Mon-26 Tue at Bob's lab
- Curved mirror characterization
- R&T measurement
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80
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Mon Mar 25 18:34:25 2013 |
Koji | General | General | OMC building plan / procedure ~ Mar 25 Mon | 25 March (Mon):
Inspect the test PZT assembly
- => Give it to Bob. (done)
Glue topside components (done)
- Clean up the table for the gluing work.
- Prepare the transport fixture on the table.
- Glass breadboard
- Pick breadboard #1 (cf. [ELOG 27])
- Wipe the entire glass breadboard with IPA
- Place the breadboard in the fixture (check which is the upper side)
- Gluing
- Set the gluing template on the breadboard.
- Place all of the glass components on the plate (just for confirmation)
- Wipe (locally) both surfaces to be glued.
- Apply glue on the component to be glued
- Align the components in the template. Use the cantilever pusher if necessary.
- Illuminate UV
- Repeat the above process for all of the components.
- Close the transport fixture and wrap with Al foil
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81
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Mon Mar 25 19:31:16 2013 |
Koji | Optics | General | OMC Top-side gluing | [Koji Jeff Zach]
AAA
BBB
CCC
DDD
|
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82
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Tue Mar 26 22:33:07 2013 |
Koji | General | General | Loan for the OMC building | Loan from PSL Lab
- 300mm mirror with Ultima mount and pedestal
- Isopropanol small glass bottleReturned on Apr 12 2013.
- Newport 422-1S single-axis stage
Loan from ATF Lab
- 50/50 Cube BS 05BC16NP.9 without mount
- 1.5" pedestal (1/4-20 thread), 1/4" shim (1/4-20 through-hole), 1/8" shim (1/4-20 through-hole): 2 eachReturned on Aug 22, 2013.
- PBS & PBS mount
- Newport 422-1S single-axis stageReturned on Apr 12 2013.
- 10 ft BNC cable x 2
- some more BNC (labeled as ATF)Returned on May 20 2013.
- Y1-1037-45P with ultima mount 3inch post
- 1x Newfocus 5104 mirrorReturned on Aug 22, 2013.
- 4x ForkReturned on Aug 22, 2013.
Loan from 40m
- 4 BNC Ts and 1 BNC Ys
- 4 BNC Ts and 1 BNC YsReturned on May 20 2013.
- 6 BNC cablesReturned on May 20 2013.
- SONY CCD / CCD Monitor / CCD power supply
- Optical fiber tester (for fiber alignment) Returned on Apr 9 2013. |
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83
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Wed Mar 27 20:54:45 2013 |
Koji | General | General | OMC building plan / procedure ~ Mar 26 Mon | 26 March (Tue):
- Curved mirror characterization (Koji, done)
- Input optics for the cavity locking (Zach)
Faraday, BB EOM, Resonant EOM, AOM, MZ |
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84
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Wed Mar 27 20:54:54 2013 |
Koji | General | General | OMC building plan / procedure ~ Mar 27 Wed | 27 March (Wed)
- AOM drift investigation (Lisa, Zach)
- Cavity input optics ~ Fiber coupling (Zach)
Action Items
- Glue curved mirror sub-assys.
- R&T measurement
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85
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Wed Mar 27 20:55:10 2013 |
Koji | General | General | OMC building plan / procedure ~ Mar 28 Thu | 28 March (Thu):
- Rebuild the bottom template in the lab
- Place the bottom template on the OMC
- Glue the PZTs on the mounting prisms (x2)
- Glue the curved mirrors on the PZTs (x2)
- R&T measurement
- Placing optics on the OMC breadboard
- Better coupling to the fiber
- Matching to the OMC cavity
29 March (Fri):
Start gluing bottom side: Set 4 cavity mirrors and 1 HR mirror
and try to resonate beam. Glue when OK.
Place BS and DCPD mounting brackets. Glue when OK.
Friday: Place QPDs and rest of optics. Glue when OK.
WB 1 April
- Testing at CIT
- Transmission / Coupling / Loss
- FSR / TMS
- Power dependence
- PZT position dependence
- Back scattering
- Openloop TF
- PZT TF
- Noise measurement
- Epoxy cure bake at CIT
- Retest at CIT
WB 8 April or after
- Packing
- Shipping - Shipping box?
- Optical Testing at LLO (2 days anticipated)
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88
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Mon Apr 1 03:13:41 2013 |
Koji | Optics | General | Failure of PZT-glass joints | [Koji, Jeff, Zach, Lisa]
We glued a test PZT-mirror assembly last week in order to make sure the heat cure of the epoxy does not make any problem
on the glass-PZT joints. The assembly was sent to Bob for the heat treatment. We received the assembly back from Bob on Wednesday.
We noticed that the assembly after the heat cure at 100degC had some voids in the epoxy layer
(looking like the fused silica surface was only 70% "wetted" by the epoxy).
The comparison of the assembly before and after the heat treatment is found in the slideshow at the bottom of the entry.
Initially our main concern was the impact to the control and noise performance.
An unexpected series resonance on the PZT transfer function and unwanted noise creation by the imperfect bonding may terribly ruin the IFO sensitivity.
In reality, after repeated poking by fingers, the PZT-prism joint was detached. This isn't good at all.
Note that there is no sign of degradation on the glass-glass joint.
We investigated the cause of this like:
- Difference of thermal expansion (3ppm/C PZT vs 0.55ppm/C fused silica)
- Insufficient curing of epoxy by UV (but this is the motivation of the heat cure)
Our resolution up to this point is to switch the glue to EP30-2. This means we will go through the heat cure test again.
Unfortunately there is no EP30-2 in stock at Caltech. We asked MIT to send us some packets of EP30-2.
Hardness of the epoxies is another concern. Through the epoxy investigation, we learned from Noliac that the glue for the PZT
should not be too hard (stiff) so as not to constrain the deformation of the PZT. EP30-2 has Shore D Hardness of 75 or more,
while Optocast UV epoxy has 88, and EPOTEK Epoxies, which Noliac suggested for gluing, has ~65. This should also be
confirmed by some measurement. We will also ask Master Bond if they have information regarding the effect of curing
temperature on the hardness of the epoxy. EP30-2 can be cured anywhere between RT and 200F (it's service range is up to 300F).
However, the entire breadboard, with the curved mirror sub-assemblies, will need to be baked at 110C to cure the UV Bond epoxy.
We hope that exposure to relatively higher temps doesn't harden the EP30-2. The EP30-2 data sheet recommends an epoxy
thickness of 80-120 microns which is much thicker than we would like.
We also don't have a way tocontrol the thickness; though we could add glass spheres to the epoxy to control the thickness.
The thickness of the EP30-2 used to bond the metal wire guide prism on the core optics is much thinner at 15-25 microns.
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89
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Mon Apr 1 03:23:48 2013 |
Koji | Optics | General | UV power calibration | [Koji Lisa Jeff Zach]
Eric G bought a UV power meter from American Ultraviolet.
Our UV illuminator was calibrated by this power meter.
The first blast (i.e. cold start): 3.9W/cm^2
After many blasting: 8.3W/cm^2
The spec is 20W/cm^2 |
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90
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Mon Apr 1 10:28:03 2013 |
Koji | Mechanics | General | Additional UV blast for the top surface | [Koji, Lisa, Jeff, Zach]
Jeffs concern after talking with the glue company (EMI) was that the UV blast for the top side was not enough.
First we wanted to confirm if too much blasting is any harmful for the glue joint.
We took a test joint of FS-FS with the UV epoxy. We blasted the UV for 1min with ~15mm distance from the joint.
After the observation of the joint, we continued to blast more.
In total, we gave additional 5min exposure. No obvious change was found on the joint.
Then proceed to blast the OMC top again. We gave 1 min additional blast on each glue joint.
 
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91
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Mon Apr 1 18:17:01 2013 |
Koji | Optics | General | Mirror curvature center test | Locations of the curvature minimum on the OMC curved mirrors have been measured.
Motivation:
When a curved mirror is misaligned, the location of the curvature center is moved.
Particularly, our OMC mirror is going to be attached on the PZT and the mounting prism with the back surface of the mirror.
This means that a curved mirror has inherent misalignment if the curvature minimum of the curved mirror is shifted from the center of the mirror.
Since we have no ability to control mirror pitch angle once it is glued on the prism, the location of the curvature minima
should be characterized so that we can oush all of the misalignment in the horizontal direction.
Measurement technique:
When a curved mirror is completely axisymmetric (in terms of the mirror shape), any rotation of the mirror does not induce change on the axis of the refected beam.
If the curvature minimum is deviated from the center of the mirror, the reflected beam suffer precession. As we want to precisely rotate the mirror, we use the gluing
fixture for the PZT assembly. In this method, the back surface of the curved mirror is pushed on the mounting prism, and the lateral position of the mirror is precisely
defined by the fixture. As you rotate the mirror in clockwise viewing from the front, the spot moves in counter clockwise on the CCD.
Setup and procedure:
The mounting prism (#21) is placed on the gluing fixture. A curved mirror under the test is loaded in the fixture with no PZT.
i.e. the back surface is aligned by the mounting prism. The fixing pressure is applied to the curved mirror by the front plate
with spring loads. The mirror needs be pushed from the top at least once to keep its defined position in the fixture.
The incident beam is slightly slated for the detection of the reflected spot. The beam is aligned and hits the center of the mirror as much as possible.
The position of the spot on the CCD (WinCamD) is recorded, while the mirror is rotated 90deg at once. The rotation of the mirror is defined as shown in the figure below.
The angle origin is defined by the arrow mark of the mirror and rotated in clockwise being viewed from the front face. The mirror is rotated 540deg (8points) to check
the reproducibility.
Measurement result:
8 point for each mirror is fitted by a circle. The fitting result provides the origin and radius of the circle, and the angle correspond to mirror angle of 0deg.
Analysis:
d: distance of the curvature minimum and the mirror center (quantity to be delived)
D: distance of the prove beam spot from the center of the mirror
R: Radius of curvature of the mirror
theta_R: angle of incidence/reflection
The interesting consequence is that precession diameter (X-X') on the CCD does not depend on the spot position on the mirror.
This ensures the precision of the measurement. In the measurement, the radius of the precession (r = (X-X')/2) is obtained.
Therefore,
d = r R / (2 L)
Mirror name, distance[mm]
C1: 0.95
C3: 1.07
C4: 1.13
C5: 0.97
C6: 0.73
C7: 1.67
C8: 2.72
C9: 1.05
C10: 0.41
C11: 0.64
C12: 0.92
C13: 0.14
Resolution:
The angle to be rotated is depicted in the following plot for each mirror.
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92
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Wed Apr 3 17:39:38 2013 |
Koji | Mechanics | Characterization | Calibration of the test PZTs before the glue test | We want to make sure the responses of the PZT actuator does not change after the EP30-2 gluing.
A shadow sensor set up was quickly set-up at the fiber output. It turned out the ring PZTs are something really not-so-straightforward.
If the PZT was free or just was loosely attached on a plane by double-sided tape, the actuation response was quite low (30% of the spec).
After some struggle, I reached the conclusion that the PZT deformation is not pure longitudinal but some 3-dimensional, and you need to
use a "sandwitch" with two flat surfaces with some pressue.
I turned the setup for horizontal scans to the vertical one, and put the PZT between quarter-inch spacers.
Then two more spacers are placed on the stack so that the weight applies the vertical pressure on the PZT.
This is also use ful to adjust the height of the shadow.
The calibration plot is attached. It gives us ~21k V/m.
Voltage swing of 150V results the output voltage change of ~50mV. This is pretty close to what is expected from the spec (16nm/V).
The PZT#3 (which had the mirror glued on) showed significantly large response.
Test PZT #1: 17.4nm/V
Test PZT #2: 17.2nm/V
Test PZT #3: 30.6nm/V
UHV PZT #24: 17.6nm/V
These numbers will be checked after the heat cure of EP30-2 |
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93
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Wed Apr 3 18:42:45 2013 |
Koji | Optics | General | EP30-2 gluing test | EP30-2 gluing test
|
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95
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Thu Apr 4 01:35:04 2013 |
Koji | Optics | Characterization | Mode matching to the OMC cavity | The fiber output was matched with the lenses on a small bread board.
The detailed configuration is found in the following elog link.
http://nodus.ligo.caltech.edu:8080/OMC_Lab/105 |
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96
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Thu Apr 4 01:43:06 2013 |
Koji | Optics | Characterization | Mirror T measurement | [Zach, Koji]
The measurement setup for the transmission measurement has been made at the output of the fiber.
- First, we looked at the fiber output with a PBS. It wasn't P-pol so we rotated the ourput coupler.
What we found was that it wasn't actually linearly polarized.
So the input coupler was rotated to correct it. This terribly misaligned the input coupling.
After some iteration of rotating and aligning the input/output couplers, we obtained reasonable
extiction ratio like 10mW vs 100uW (100:1) with 11mW incidence. (Where is the rest 0.9mW!?)
- The P-pol (transmission) out of PBS goes into the mirror. Here we tested mirror A1.
The mirror is mounted on the prism mount supported by a rotational stage for precise angle adjustment
We limited the input power down to 5mW so that we can remove the attenuator on the power meter.
The reading of the power meter was fluctuating, indeed depending on MY position.
So we decided to turn off the lighting of the room. This made the reading very stable.
The offset of the power meter was -0.58uW
The transmitted power for the normal incidence was 39.7uW with the incident 4.84mW.
[39.7-(-0.58)] / [4.84*1000-(-0.58)] *10^6 = 8320 ppm
The transmitted power for the 4deg incidence was 38.0uW with the incident 4.87mW.
[38.0-(-0.58)] / [4.87*1000-(-0.58)] *10^6 = 7980 ppm
cf. The specification is 7931ppm
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97
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Thu Apr 4 23:44:52 2013 |
Koji | Optics | Configuration | Beam launched into fiber | We had to move our flipper mirror to share the beam between Peter's setup and ours as our flipper is at the place where the ISS PD array base is supposed to be!
There was no place to insert the flipper in the setup. We (Peter and Koji) decided to move the laser back for ~2".
This entirely changed the alignment of the setup. The fiber coupler was my reference of the alignment.
Once the beam is aligned, I check the coupling to the fiber. It was 50%.
I tweaked the lens and eventually the coupling is improved to 83%. (24.7mW incident, 20.4mW obtained.)
Then, I started to check the AOM path. I noticed that the 1st (or -1st) order beam is very weak.
The deflection efficiency is ~0.1%. Something is wrong.
I checked the driver. The driver's coupler output (1:10) show the amplitude ~1V. (good)
I check the main output by reducing the offset. When the coupler output is 100mV, the main output was 1V. (good)
So is the AOM itself broken??? |
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98
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Fri Apr 5 14:39:26 2013 |
Koji | Mechanics | Characterization | Calibration of the test PZTs after the heat cure | We attached fused silica windows on the test PZTs. http://nodus.ligo.caltech.edu:8080/OMC_Lab/93
The glued assemblies were brought to Bob's bake lab for the heat cure. There they are exposed to 94degC heat for two hours (excluding ramp up/down time).
After the heat cure, we made the visual inspection.
The photos are available here.
Pre-bake
Test PZT #1: 17.4nm/V
Test PZT #2: 17.2nm/V
Test PZT #3: 30.6nm/V
Post-bake
Test PZT #1: 27.2 nm/V
Test PZT #2: 26.9 nm/V
Test PZT #3: 21.4 nm/V
Measurement precision is ~+/-20%
Spec is 14nm/V |
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100
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Mon Apr 8 11:11:37 2013 |
Koji | Optics | Characterization | More Mirror T measurement | More Ts of the mirrors were measured.
A mirror specification:
Request: 8300+/-800 ppm
Data sheet: 7931ppm
C mirror specification:
Request: 50+/-10 ppm
Data sheet: 51.48ppm or 46.40ppm
Mirror | P_Incident P_Trans P_Offset | T_trans
| [mW] [uW] [uW] | [ppm]
-------+------------------------------+---------
A1 | 10.28 82.9 -0.205 | 8.08e3
A2 | ----- ----- ------ | ------
A3 | 10.00 83.2 -0.205 | 8.34e3
A4 | 10.05 80.7 -0.205 | 8.05e3
A5 | 9.94 81.3 -0.205 | 8.20e3
A6 | 10.35 78.1 -0.205 | 7.57e3
A7 | 10.35 77.8 -0.205 | 7.54e3
A8 | 10.30 78.0 -0.205 | 7.60e3
A9 | 10.41 84.1 -0.205 | 8.10e3
A10 | 10.35 77.3 -0.205 | 7.49e3
A11 | 10.33 77.9 -0.205 | 7.56e3
A12 | 10.34 78.7 -0.205 | 7.63e3
A13 | 10.41 85.4 -0.205 | 8.22e3
A14 | 10.34 84.4 -0.205 | 8.18e3
-------+------------------------------+---------
C1 | 10.30 0.279 -0.225 | 48.9
C2 | ----- ----- ------ | ------
C3 | 10.37 0.240 -0.191 | 41.6
C4 | 10.35 0.278 -0.235 | 49.6
C5 | 10.40 0.138 -0.235 | 35.9 => PZT assembly #2
C6 | 10.34 0.137 -0.235 | 36.0 => PZT assembly #1
C7 | 10.37 0.143 -0.229 | 35.9
C8 | 10.41 0.224 -0.237 | 44.3
C9 | 10.36 0.338 -0.230 | 54.8
C10 | 10.39 0.368 -0.228 | 57.4
C11 | 10.38 0.379 -0.209 | 56.6
C12 | 10.28 0.228 -0.238 | 45.3
C13 | 10.36 0.178 -0.234 | 39.8
-------+------------------------------+---------
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101
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Mon Apr 8 11:29:08 2013 |
Koji | Optics | Characterization | Mirror/PZT Characterization links | |
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102
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Mon Apr 8 11:49:18 2013 |
Koji | Mechanics | Characterization | PZT actuator tested at LLO | Test result of the PZTs by Valera and Ryan
PZT Length Angle
# [nm/V] [urad/um]
11 14.5 17.6
12 13.8 17.8
13 11.2 25.0
14 14.5 6.6
15 12.5 10.6
21 14.5 9.7
22 13.8 28.8
23 14.5 6.8 ==> Assembly #2
24 18.5 51.7 ==> Used for prototyping
25 17.1 13.8
26 14.5 6.6 ==> Assembly #1
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103
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Mon Apr 8 20:56:52 2013 |
Koji | Optics | Configuration | PZT & Curverd Mirror arrangement | Assembly #1:
Mounting Prism #16
PZT #26
Mirror C6
Assembly #2:
Mounting Prism #20
PZT #23
Mirror C5 |
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104
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Mon Apr 8 21:11:14 2013 |
Koji | Optics | General | PZT assembly gluing | [Jeff, Zach, Koji]
PZT assembly gluing
Glue gun -> to be returned to MIT
Fixtures x2
Al bases, spacers
spare screws
mirrors / prisms / PZTs
IPA bottle
clean tools x2
first contact kit
gloves (7.5)
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105
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Mon Apr 8 23:42:33 2013 |
Koji | Optics | Configuration | Fake OMC roughly aligned | Mode matching:
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106
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Tue Apr 9 13:56:09 2013 |
Koji | Optics | General | PZT assembly post gluing / pre baking pictures |
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108
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Thu Apr 11 15:10:22 2013 |
Koji | General | General | OMC Progress | [Zach, Jeff, Koji]
- Jeff configured the bottom side template to have a nominal value
obtained from the solid works model. Note that the thickness of the
curved mirrors are 6mm in the model. He added 0.3mmx2 to the dimensions.
- Jeff located the template on the breadboard such that each side has
the same amount of hanging out.
- Micrometer values
- The one closest to the input mirror (CM1) 0.07
- The other one on CM1 0.24
- The one closest to the output mirror (CM2) 0.17
- The other one on CM2 0.30
/------------\
0.17 0.07
\------------/
0.30 0.24
- Now the template is ready to accept the OMC optics.
- Zach and Koji finished a series of measurements for the test OMC.
Modulation depth:
- We scanned the laser PZT and recorded the data.
CH1: Reflection DC
CH2: PDH Error
CH3: Transmission (Magnified)
CH4: Transmission
- We should be able to obtain the estimation of the modulation depth and the finesse from this measurement.
- Rough calculation of the modulation depth is 0.19
Transmission:
- Incident 16.3mW
- Transmission 15.1mW
- This gave us the raw transmission of 92.6%ish.
- The modulation depth of 0.19 corresponds to 1.8% of the incident power
- The carrier reflection is almost dominated by the mode mismatch. (Note: We did not have a good resolution for the refl beam) =>3.2%
- In total:The incident useful carrier power was 15.4mW ==> Throughput 98%
- There is slight headroom to increase the transmission by cleaning the mirrors.
FSR/Finesse:
- As our AOM is not functioning now, phase modulation sidebands are injected with the BBEOM.
- In principle, we can't expect any signal at the transmission at around the FSR frequency.
- If we apply small locking offset, the split peaks appear at the FSR frequency. The frequency of the dip corresponds to the FSR.
- We probably can extract the finesse of the cavity from this measurement. Lisa is working on this.
HOM/Finesse:
- The same PM injection gives us the frequency of the HOMs.
- We found that our EOM can work until ~500MHz.
- We could characterize the cavity resonance structure more than a single FSR. |
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109
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Fri Apr 12 09:25:31 2013 |
Koji | Optics | Characterization | Alignment of the OMC (without glue) | [Zach Koji]
The first attempt not to touch the curved mirrors did not work. (Not surprising)
The eigenmode is not found on the mirror surface.
We decided to touch the micrometers and immediately found the resonance.
Then the cavity alignment was optimized by the input steering mirrors.
We got the cavity length L and f_TMS/f_FSR (say gamma, = gouy phase / (2 pi) ) as
L=1.1347 m (1.132m nominal)
gamma_V = 0.219176 (0.21879 nominal)
gamma_H = 0.219418 (0.21939 nominal)
This was already sufficiently good:
- the 9th modes of the carrier is away from the resonance 10-11 times
of the line width (LW)
- the 13th modes of the lower f2 sideband are 9-10 LW away
But
- the 19th modes of the upper f2 sideband are 1-3 LW away
This seems to be the most dangerous ones.
and
- The beam spots on the curved mirrors are too marginal
So we decided to shorten the cavity round-trip 2.7mm (= 0.675mm for each micrometer)
and also use the curved mirrors to move the eigenmode toward the center of the curved mirrors.
After the movement the new cavity length was 1.13209 m.
The spot positions on the curved mirrors are ~1mm too close to the outside of the cavity.
So we shortened the outer micrometers by 8um (0.8 div).
This made the spot positions perfect. We took the photos of the spots with a IR sensor card.
The measured cavity geometry is (no data electrically recorded)
L=1.13207 m (1.132m nominal, FSR 264.8175MHz)
gamma_V = 0.218547 (0.21879 nominal, 57.8750MHz)
gamma_H = 0.219066 (0.21939 nominal, 58.0125MHz)
- the 9th modes of the carrier is 11-13 LW away
- the 13th modes of the lower f2 sideband are 5-8 LW away
- the 19th modes of the upper f2 sideband are 4-8 LW away
The raw transmission is 94.4%. If we subtract the sidebands and
the junk light contribution, the estimated transmission is 97.6%.
Note:
Even if a mirror is touched (i.e. misaligned), we can recover the good alignment by pushing the mirror
onto the fixture. The fixture works pretty well!
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110
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Sat Apr 13 21:06:02 2013 |
Koji | Optics | General | OMC Bottom-side: cavity glued | [Jeff, Zach, Lisa, Koji]
Gluing of the cavity mirrors went very well!!!
Preparation
- Checked if the cavity is still resonating. => Yes.
- Checked the FSR: 264.251MHz => 1.1345m
2.5mm too long => Move each micrometer by 0.625mm backward
- FSR&TMS (I)
Aligned the cavity again and checked the FSR: 264.8485MHz => 1.13194m
TMS(V): 58.0875MHz => gamma_V = 0.219324
TMS(H): 58.1413MHz => gamma_H = 0.219526
the 9th modes of the carrier is 9.7-10.4 line width (LW) away from the carrier resonance
the 13th modes of the lower f2 sideband are 9.2-10.2 LW away
the 19th modes of the upper f2 sideband are 0.3-1.8 LW away
We found that this coincidence of the resonance can be corrected by shortening the cavity round-trip by 0.5mm
- Spot positions (I)
The spots on the curved mirrors were ~1mm too much inside (FM side). In order to translate the cavity axis,
MM2 and MM4 were pushed by θ
θ/2.575 = 1mm ==> θ = 2.6 mrad
The separation of the micrometers are ~20mm
d/20mm = 2.6mrad ==> d = 52um
1div of the micrometer corresponds to 10um => 5div = 50um
- Move the micrometers and adjusted the input steering to recover the alignment.
- In any case we were confident to adjust the FSR/TMS/spot positions only with the micrometers
BS1/FM1/FM2 gluing
- Aligned the cavity
- Glued BS1/FM1/FM2 one by one while the cavity resonance was maintained.
FM2 was slipping as the table is not leveled well and the fixture was not supporting the optic.
- FSR&TMS (II)
FSR: 264.964875MHz => 1.13144m (Exactly 0.5mm shorter!)
TMS(V): 58.0225MHz => gamma_V = 0.218982
TMS(H): 58.1225MHz => gamma_H = 0.219359
the 9th modes of the carrier is 10.3~11.7 LW away
the 13th modes of the lower f2 sideband are 7.4~9.3 LW away
the 19th modes of the upper f2 sideband are 1.5~4.4 LW away
- Spot positions (II)
Looked OK.
CM2 gluing
- Glued CM2. The mirror was supported from the back with allen keys.
- FSR&TMS (III)
FSR: 264.9665625MHz => 1.13144m
TMS(V): 58.1275MHz => gamma_V = 0.219377
TMS(H): 58.0813MHz => gamma_H = 0.219202
the 9th modes of the carrier is 10.2~10.9 LW away
the 13th modes of the lower f2 sideband are 8.5~9.4 LW away
the 19th modes of the upper f2 sideband are 1.4~2.7 LW away
- Spot positions (III)
Looked slightly off at CM2. Pushed MM2 by 4um.
CM1 gluing
- Glued CM1.
- FSR&TMS (IV)
FSR: 264.964875MHz => 1.13144m
TMS(V): 58.06625MHz => gamma_V = 0.219145
TMS(H): 58.08625MHz => gamma_H = 0.219220
the 9th modes of the carrier is 10.8~11.1 LW away
the 13th modes of the lower f2 sideband are 8.2~8.6 LW away
the 19th modes of the upper f2 sideband are 2.6~3.2 LW away
- Spot positions (final confirmation)
Looked OK.
Final measurement
- After everything was finished, more detailed measurement has been done.
- FSR&TMS (final)
FSR: 264.963MHz => 1.13145m
TMS(V): 58.0177MHz => gamma_V = 0.218966
TMS(H): 58.0857MHz => gamma_H = 0.219221
the 9th modes of the carrier is 10.8~11.7 LW away
the 13th modes of the lower f2 sideband are 7.3~8.6 LW away
the 19th modes of the upper f2 sideband are 2.6~4.5 LW away
Final values for the micrometers
- MM1: The one closest to the input mirror (CM1) 0.78mm
- MM2: The other one on CM1 0.89
- MM3: The one closest to the output mirror (CM2) 0.90
- MM4: The other one on CM2 0.90
/------------\
0.90 0.78
\------------/
0.90 0.89
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111
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Tue Apr 16 00:40:45 2013 |
Koji | Optics | General | PD/QPD path gluing ~ preparation | [Jeff Koji]
- Placed the optics on the PD/QPD path
- Checked the alignment of the beam on the dummy PD/QPD mounts
- There is a bit of (~0.5mm) shift of the spot position from the center. Mainly downward. This is well within a ball park of the PD mounts.
- The PD/QPD path gluing will take place tomorrow.
- Went to the 40m and received the DCPDs from Bob's lab.
- Took six ISC QPDs for the sake of the OMCs.
- They are now in the OMC lab.
- Measured the B mirror / E mirror R&Ts.
- Found anomalously high loss (3%) for the B mirrors (BSs)
- Went through the all mirrors. Some mirrors (3 or 4) seemed less lossy (<~1%). They will be used for the DCPD BS. |
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112
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Tue Apr 16 08:12:14 2013 |
Koji | Optics | Characterization | Further More Mirror T measurement | T&Rs of the B mirrors and some of the E mirrors are measured.
I found that these BSs have high loss (1%~3%) . As this loss will impact the performance of the squeezer
we should pick the best ones for the DCPD path. B5, B6, and B12 seems the best ones.
Mirror | P_Incident P_Trans P_Refl | T R loss |
| [mW] [mW] [mW] | |
-------+--------------------------------------+-------------------------------------------+
B1 | 13.80+/-0.05 7.10+/-0.05 6.30+/-0.05 | 0.514+/-0.004 0.457+/-0.004 0.029+/-0.005 |
B2 | 14.10+/-0.05 6.50+/-0.05 7.15+/-0.05 | 0.461+/-0.004 0.507+/-0.004 0.032+/-0.005 |
B3 | 13.87+/-0.05 7.05+/-0.05 6.55+/-0.05 | 0.508+/-0.004 0.472+/-0.004 0.019+/-0.005 |
B4 | 13.85+/-0.05 6.78+/-0.05 6.70+/-0.05 | 0.490+/-0.004 0.484+/-0.004 0.027+/-0.005 |
B5 | 13.65+/-0.05 6.93+/-0.05 6.67+/-0.05 | 0.508+/-0.004 0.489+/-0.004 0.004+/-0.005 |
B6 | 13.75+/-0.05 6.70+/-0.05 6.92+/-0.05 | 0.487+/-0.004 0.503+/-0.004 0.009+/-0.005 |
B7 | 13.83+/-0.05 7.00+/-0.05 6.60+/-0.05 | 0.506+/-0.004 0.477+/-0.004 0.017+/-0.005 |
B8 | 13.90+/-0.05 6.95+/-0.05 6.68+/-0.05 | 0.500+/-0.004 0.481+/-0.004 0.019+/-0.005 |
B9 | 13.84+/-0.05 6.95+/-0.05 6.70+/-0.05 | 0.502+/-0.004 0.484+/-0.004 0.014+/-0.005 |
B10 | 13.97+/-0.05 6.98+/-0.05 6.72+/-0.05 | 0.500+/-0.004 0.481+/-0.004 0.019+/-0.005 |
B11 | 13.90+/-0.05 7.05+/-0.05 6.70+/-0.05 | 0.507+/-0.004 0.482+/-0.004 0.011+/-0.005 |
B12 | 13.90+/-0.05 6.98+/-0.05 6.78+/-0.05 | 0.502+/-0.004 0.488+/-0.004 0.010+/-0.005 |
-------+--------------------------------------+-------------------------------------------+
Mirror | P_Incident P_Trans P_Refl | T R loss |
| [mW] [uW] [mW] | [ppm] |
-------+-------------------------------------------+------------------------------------------+
E4 | 13.65+/-0.05 0.0915+/-0.0005 13.50+/-0.05 | 6703+/-44ppm 0.989+/-0.005 0.004+/-0.005 |
E12 | 13.75+/-0.05 0.0978+/-0.0005 13.65+/-0.05 | 7113+/-45 0.993+/-0.005 0.000+/-0.005 |
E16 | 13.90+/-0.05 0.0975+/-0.0005 13.30+/-0.05 | 7014+/-44 0.957+/-0.005 0.036+/-0.005 |
-------+-------------------------------------------+------------------------------------------+
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