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  Coating Ring-down Measurement Lab elog, Page 17 of 18  Not logged in ELOG logo
Entry  Fri Mar 27 15:32:29 2020, Gabriele, General, Measurements, S1600789 S1600791 
2020-03-27


3:31pm in chamber

S1600789 in CR1
S1600791 in CR2


3:32pm roughing
pump on
3:40pm turbo pump on
Entry  Tue Mar 31 13:12:21 2020, Alena, General, Measurements, S1600784 S1600785 S1600789 S1600791 
2020-03-31


1:00 pm in chamber

S1600784in CR1
S1600785 in CR2
S1600789 in CR3
S1600791
in CR4


1:05 pm roughing pump on
1:14 pm turbo pump on
Entry  Tue Mar 31 18:56:31 2020, Gabriele, General, Measurements, S1600775 S1600788 
2020-03-31


7:05pm in chamber

S1600775 in CR1
S1600788 in CR2


7:09pm roughing
pump on
7:18pm turbo pump on
Entry  Thu Apr 2 14:07:18 2020, Gabriele, General, Measurements, S1600784 S1600785 S1600789 S1600791 
2020-04-02


2:05 pm in chamber

S1600784 in CR1
S1600785 in CR2
S1600789 in CR3
S1600791
in CR4


2:07 pm roughing pump on
2:17 pm turbo pump on
Entry  Fri Apr 3 10:26:00 2020, Gabriele, General, Measurements, S1600775 S1600788 
2020-04-03


10:24am in chamber

S1600775 in CR1
S1600788 in CR2


10:25am roughing
pump on
10:35am turbo pump on
Entry  Tue Apr 7 10:06:43 2020, Gabriele, General, Measurements, S1600775 S1600784 S1600788 S1600791 
2020-04-07


10:05 am in chamber

S1600775 in CR1
S1600784 in CR2
S1600788 in CR3
S1600791
in CR4


10:06 am roughing pump on
10:16 am turbo pump on
Entry  Tue Apr 7 15:50:24 2020, Gabriele, General, Measurements, S1600785 S1600789 
2020-04-07


3:50pm in chamber

S1600785 in CR1
S1600789 in CR2


3:53pm roughing
pump on
4:03pm turbo pump on
Entry  Thu Apr 9 13:47:38 2020, Gabriele, General, Measurements, S1600775 S1600784 S1600788 S1600791 
2020-04-09


1:46 pm in chamber

S1600775 in CR1
S1600784 in CR2
S1600788 in CR3
S1600791
in CR4


1:47 pm roughing pump on
1:57 pm turbo pump on
Entry  Fri Apr 10 10:20:01 2020, Gabriele, General, Measurements, S1600785 S1600789 
2020-04-10


10:17am in chamber

S1600785 in CR1
S1600789 in CR2


10:20am roughing
pump on
10:30am turbo pump on
Entry  Tue Apr 14 12:19:57 2020, Gabriele, General, Measurements, S1600775 S1600784 S1600788 S1600791 
2020-04-14


12:18 pm in chamber

S1600775 in CR1
S1600784 in CR2
S1600788 in CR3
S1600791
in CR4


12:19 pm roughing pump on
12:29 pm turbo pump on
Entry  Tue Apr 14 18:35:59 2020, Gabriele, General, Measurements, S1600785 S1600789 
2020-04-14


6:35pm in chamber

S1600785 in CR1
S1600789 in CR2


6:40pm roughing
pump on
6:48pm turbo pump on
Entry  Thu Apr 16 14:23:11 2020, Gabriele, General, Measurements, S1600775 S1600784 S1600788 S1600791 
2020-04-16


2:21 pm in chamber

S1600775 in CR1
S1600784 in CR2
S1600788 in CR3
S1600791
in CR4


2:22 pm roughing pump on
2:30 pm turbo pump on
Entry  Fri Apr 17 10:18:17 2020, Gabriele, General, Measurements, S1600785 S1600789 
2020-04-17


10:17am in chamber

S1600785 in CR1
S1600789 in CR2


10:20am roughing
pump on
10:28am turbo pump on
Entry  Thu Apr 23 14:02:25 2020, Gabriele, General, Measurements, S1600776 
2020-04-23


2:00pm in chamber

S1600776 in CR1


2:02pm roughing pump on
2:12pm turbo
pump on
Entry  Fri Apr 24 10:53:40 2020, Gabriele, General, Measurements, S1600801 S1600802 S1600803 S1600804 
2020-04-24


10:51 am in chamber

S1600801 in CR1
S1600802 in CR2
S1600803 in CR3
S1600804
in CR4


10:52 am roughing pump on
11:00 am turbo pump on
Entry  Mon Apr 27 10:26:29 2020, Gabriele, General, Measurements, S1600805 S1600806 S1600807 S1600808 
2020-04-24


10:25 am in chamber

S1600805 in CR1
S1600806 in CR2
S1600807 in CR3
S1600808
in CR4


10:28 am roughing pump on
10:38 am turbo pump on
Entry  Thu May 28 11:43:19 2020, Gabriele, General, Measurements, S1600801 S1600802 S1600803 S1600805 S1600806 
2020-05-28


11:40 am in chamber

S1600801 in CR1
S1600802 in CR2
S1600803 in CR3
S1600805
in CR4
S1600806 in CR0


11:43 am roughing pumps on
11:53 am turbo pump CR1-4 on
 turbo
pump CR0 on not on yet
Entry  Fri May 29 10:10:51 2020, Gabriele, General, Measurements, S1600806 
2020-05-28


10:00 am in chamber

S1600806 in CR1


10:05 am roughing pumps on
10:15
am turbo pump CR1-4 on
Entry  Tue Jun 2 10:16:40 2020, Gabriele, General, Measurements, S1600801 S1600802 
2020-06-02


10:15 am in chamber

S1600801 in CR1
S1600802 in CR2


10:20 am roughing
pumps on
10:30 am turbo pump CR1-4 on
Entry  Fri Jun 5 18:55:27 2020, Gabriele, General, Measurements, S1600803 GaAs 
2020-06-05


6:50 pm in chamber

S1600803 in CR1
GaAs in CR2


6:55 pm roughing pumps
on
7:05 pm turbo pump CR1-4 on
Entry  Tue Jun 9 11:04:28 2020, Gabriele, General, Measurements, GaAs S1600805 
2020-06-09


11:00 am in chamber

GaAs in CR1
S1600805 in CR2


11:04 am roughing
pumps on
11:15 am turbo pump CR1-4 on
Entry  Mon Jun 15 19:32:31 2020, Gabriele, General, Measurements, S1600803 GaAs 
2020-06-15


7:32 pm in chamber

S1600803 in CR1
GaAs in CR2


7:36 pm roughing pumps
on
7:46 pm turbo pump CR1-4 on
Entry  Tue Jun 16 15:43:29 2020, Gabriele, General, Measurements, S1600805 
2020-06-16


3:42 pm in chamber

S1600805 in CR1


3:45 pm roughing pumps on
3:55
pm turbo pump CR1-4 on
Entry  Thu Jun 18 17:46:51 2020, Gabriele, General, Measurements, S1600806 
2020-06-18


5:45 pm in chamber

S1600806 in CR1


5:50 pm roughing pumps on
6:00
pm turbo pump CR1-4 on
Entry  Tue Jun 23 16:22:42 2020, Gabriele, General, Measurements, S1600806 
2020-06-23


4:20 pm in chamber

S1600806 in CR1


4:21 pm roughing pumps on
4:31
pm turbo pump CR1-4 on
Entry  Wed Jun 24 14:17:45 2020, Gabriele, General, Measurements, S1600805 S1600806 
2020-06-24


2:26 pm in chamber

S1600805 in CR1
S1600806 in CR1


2:27 pm roughing
pumps on
2:37 pm turbo pump CR1-4 on
Entry  Thu Jun 25 08:49:24 2020, Gabriele, General, Measurements, S1600803 S1600805 S1600806 
2020-06-25


8:47 am in chamber

S1600803 in CR1
S1600805 in CR2
S1600806 in CR3


8:49
am roughing pumps on
9:00 am turbo pump CR1-4 on
Entry  Wed Jul 1 13:43:53 2020, Gabriele, General, Measurements, S1600803 in 
2020-07-01


1:42 pm in chamber

S1600803 in CR1


1:43 pm roughing pumps on
1:53
pm turbo pump CR1-4 on
Entry  Thu Jul 2 14:43:09 2020, Gabriele, General, Measurements, S1600794 S1600795 S1600796 S1600797 
2020-07-02


2:41 pm in chamber

S1600794 in CR1
S1600795 in CR2
S1600796 in CR3
S1600797
in CR4


2:42 pm roughing pump on
2:52 pm turbo pump on
Entry  Tue Jul 7 15:40:44 2020, Gabriele, General, Measurements, S1600809 S1600810 S160081 S1600812 
2020-07-02


3:39 pm in chamber

S1600809 in CR1
S1600810 in CR2
S1600811 in CR3
S1600812
in CR4


3:40 pm roughing pump on
3:50 pm turbo pump on
Entry  Thu May 19 11:36:04 2016, Gabriele, Mechanics, Design, A first design of the disk assembly Screen_Shot_2016-05-18_at_3.41.06_PM.pngScreen_Shot_2016-05-18_at_3.40.43_PM.pngScreen_Shot_2016-05-18_at_3.41.25_PM.pngScreen_Shot_2016-05-18_at_3.41.33_PM.pngScreen_Shot_2016-05-18_at_3.41.25_PM.png
Here are some screenshots of the disk assembly and a look at how four of them will sit into the vacuum chamber. The Solidworks models are available here: D1600197

Entry  Fri May 27 02:09:37 2016, Gabriele, Mechanics, Characterization, Lowest usable mode of fused silica disks disk_75mm_0.12mm.pngdisk_75mm_1mm.pngdisk_100mm_0.4mm.pngdisk_200mm_0.4mm.png
I did some FEA simulation of fused silica disks, to identify the lowest usable eigenmode. By usable I mean a mode that has zero elastic energy stored
in the center. 




Diameter
Entry  Wed Aug 10 10:04:35 2016, Gabriele, Mechanics, Daily Progress, The prototype of the disk retain system is here 6x
Yesterday we received the prototype of the disk suspension and retain system. Everything looks good. I checked that the disk fits in the holder, and
all dimensions are good. The coil holders are out for winding, so I couldn't test the movimentation yet.

Entry  Fri Sep 23 08:11:48 2016, Gabriele, Mechanics, Daily Progress, Test of the disk retaining ring motion 
In brief, it doesn't work. The magnets and coils are strong enough to push up the ring with a sample inside, but the friction with the three alignment
pins is too large and random, so when the current to the coils is increased slowly, the ring doesn't move up smoothly (see first attached video). On
the other hand, if the current is switched on abruptly, the ring shoot to the top and stays there. However, if a disk is placed on the support, it is ejected
Entry  Tue Nov 15 10:35:11 2016, Gabriele, Mechanics, Daily Progress, Parts for laser polishing setup are here 2016-11-15_10.17.28.jpg2016-11-15_10.17.36.jpg2016-11-15_10.17.42.jpg
The parts all fit as expected. They're mounted on the stages.

Entry  Thu Jan 19 14:16:53 2017, Gabriele, Mechanics, Design, New concept for retaining ring motion 7x
Since my experiment with coil and magnets didn't work out very well, here's a new concept for the motion of the four retaining rings (all together)
using a translation stage and a picomotor. This follows the same idea put forward by Steve Penn. The translation stage is a Newport 9066-COM-V and
the picomotor (which we already have) is a Newport 8301-V. Both stage and picomotor are vacuum compatible (rated at 1e-6 Torr) and tested down to 1e-8
Entry  Tue Jan 31 11:21:44 2017, Gabriele, Mechanics, Daily Progress, Retaining ring mechanics 2017-01-31_10.30.45.jpg2017-01-31_10.30.34-1.jpg
All parts for the motion of the retaining rings have been received and are ok. We're going to clean and bake them. 

Entry  Fri Feb 10 17:16:28 2017, Gabriele, Mechanics, Daily Progress, Translation stage to move retaining rings 2017-02-10_16.32.55.jpg2017-02-10_16.33.03.jpg
This afternoon I installed the picomotor and the translation stage that will be used to move the retaining rings up and down. No partciular problem:
I only had to add some small aluminum foil shims between the ear of some rings and the square plate, to make the rings as horizontal as possible.

I tested the motion: with 300000 steps it's possible to move the rings all the way from the parked (down) position, to the up position. I
    Reply  Sat Feb 11 16:22:26 2017, Gabriele, Mechanics, Daily Progress, Translation stage to move retaining rings 
The ring motion up and down was not very smooth, again due to friction on the centering pins.

So, after centering the rings using the pins and securing the rings to the translation stage, I removed all pins.

Now the motion up and down is very smooth.
Entry  Thu Aug 10 13:36:08 2017, Gabriele, Zach, Mechanics, Configuration, ESD moved closer to disk in CR0 
We first measured the distance of the ESD from the disk in the test chamber (CR0). We had to remove the retaining ring to have reliable measurements


distance between top of the ESD and mounting plate: 12.30 mm
distance between top of the disk and mounting plate: 10.53 mm
ESD
thickness: 0.55 mm


So initially the distance between disk and ESD is 1.22 mm
    Reply  Fri Aug 11 09:22:21 2017, Gabriele, Mechanics, Configuration, ESD moved closer to disk in CR0 esd_ampl.pngesd_snr.png
The plots below compare the SNR and peak amplitude of all excited modes, in the new and old configuration. The new confgiuration is worse than the old
one. This is unexpected, since the distance between ESD and disk is smaller.

However, yesterday we found out that setting the ESD so close to the disk is very tricky, and we might have some touching.
Entry  Wed Jul 11 23:01:01 2012, janosch, Optics, Characterization, starting the multi-color scatter experiment DSCF3148.JPGDSCF3151.JPGDSCF3150.JPG
Steve Maloney, a visiting highschool teacher, and I have started to set up a new scattering experiment in the Richter lab. The idea is to take images
of large-angle scattered light using different lasers. We have one 633nm laser, and 532nm and 405nm laser pointers. The goal is to uniformly illuminate
the same disk of about 1cm diameter on a silver-coated mirror with all three colors. We use a silver-coated mirror to make sure that the light is reflected
Entry  Fri Jul 13 10:34:35 2012, janosch, Optics, Characterization, camera image 
We were confused a bit about how the camera image changes when you move the arm that holds the camera and lens around the mirror. It seems that
scattering centers move in ways that cannot be explained by a misaligned rotation axis. So we wanted to make sure that the mirror surface is actually imaged
as we intended to. We generated a white grid with 0.7cm spacing and black background on a monitor. The image that we saw is exactly how
Entry  Fri Jul 13 20:53:35 2012, janosch, Optics, Characterization, two images Green.pngRed.png
The following two pictures were taken from the same angle with green (left) and red (right) incident laser at an angle of 15deg from the incident beam
(reflected to about -5deg). Some scattering centers are collocated. The green laser power is about 5 times as high as the red laser power, but this
factor does not seem to calibrate the image well (the green image becomes too dark dividing all pixel values by 5). So there seems to be a significant
Entry  Tue Jul 17 18:32:11 2012, janosch, Optics, Characterization, purple images Red_30deg.pngPurple_30deg.png
We have the new 405nm laser pointer.  The image to the left shows the scattered light from the red laser, the image to the right scattered
light from the purple laser. Both images were taken 30deg with respect to the normal of the mirror surface. Also, we got a new gallon of Methanol. After
cleaning the mirror multiple times, the scattered light became significantly weaker. So the purple images look very different from red and green.
Entry  Wed Jul 18 18:43:34 2012, janosch, Optics, Characterization, gone with the wind Purple.avi
Here a little purple video. It starts with scattering angle around 15deg and stops at about 80deg. 
There are some clear point defects visible especially at small angles. 
I will not start to think about some other interesting details of this video before I got the new lens.
Entry  Fri Jul 20 18:35:42 2012, janosch, Optics, Characterization, purple improvements and first uncalibrated BSDF curves Purple.mp4Red.mp4Purple_BSDF.pngRed_BSDF.png
Today we improved alignment of the lens-camera arm. We discovered earlier that this alignment affects the amount of "snowfall" on the scattering
images. Looking at the latest 405nm video (see attachment), one can still see snowfall, but it is considerably weaker now and the true scatter image is
clearly visible. We took a set of scatter images at certain scattering angles and produced BSDF curves. The shape of these curves has partially to do with
Entry  Tue Jul 24 10:59:59 2012, janosch, Optics, Characterization, sum of purple and red ImageSum.png
We played around with Matlab today. The first step was to convert light wavelengths into RGB colors. In this way we can combine images taken at different
colors. The picture shows the purple and red images (stored in gray scale) in heat colormap. Then the sum of these two images is calculated in their natural
RGB colors.
Entry  Fri Oct 12 16:23:20 2012, janosch, Optics, Daily Progress, reassembled setup 
Nothing has happened since Steve, the visiting highschool teacher, has left. Meanwhile, some parts of the multi-color BRDF setup were delivered.
I assembled everything today and realigned the lasers. Everything is ready now for a three-color BRDF measurement (the previous Richter record was 2 colors).
I will claim back my video capture device as soon as possible from my neighbors and then take new images.
Entry  Fri May 20 15:18:58 2016, Gabriele, Optics, Design, Optical levers layout crime_v1.pdf
Attached a first layout of the optical lever systems. The beam spot radius on the QPD is about 0.8 mm, and the lever arm length is of the orer of 1.4-1.5
m for all four beams.

 
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