 Wed Mar 15 15:28:24 2023, Thejas , Optics, Characterization, A+ OMC Curved mirror radius of curvature
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Thanks for teh comment Koji. Yes, I did see this effect by comparing the beam sizes with and without the curved mirror. But the observation did not conform
with the expectation that the beam should focus at a distance of 1.25 m from the curved mirror (as seen in the software images). So, I plan to
use some lenses to increase the beam waist and perform the measurement. |
 Wed Jun 20 20:37:45 2012, Zach, Optics, Configuration, Topology / parameter selection 8x
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EDIT (ZK): All the plots here were generated using my MATLAB
cavity modeling tool, ArbCav |
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Thu Jun 21 03:07:27 2012, Zach, Optics, Configuration, Parameter selection / mode definition
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EDIT 2 (ZK): As with the previous post, all plots and calculations
here are done with my MATLAB cavity modeling utility, |
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Fri Jun 29 11:26:04 2012, Zach, Optics, Characterization, RoC measurement setup
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Here is the proposed RoC measurement setup. Koji tells me that this is referred to as "Anderson's method".
We would like to use a linear cavity to measure the RoC of the curved mirrors independently (before forming the ring cavity), since the degeneracy
of HOMs will make the fitting easier. |
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Sun Jul 22 15:56:53 2012, Zach, Optics, Characterization, RoC measurement setup
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Here is a more detailed version of the setup, so that we can gather the parts we will need.
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Tue Mar 5 19:37:00 2013, Zach, Optics, Characterization, eLIGO OMC visibility vs. power measurement details
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EDIT (ZK): Koji points out that (1 - Ti) should really be the non-resonant reflectivity of the aligned cavity, which is much closer to 1. However,
it should *actually* be the non-resonant reflectivity of the entire OMC assembly, including the steering mirror (see bottom of post). The steering mirror
has T ~ 0.3%, so the true results are somewhere between my numbers and those with (1 - Ti) -> 1. In practice, though, these effects are swamped by the |
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Wed Mar 6 23:24:58 2013, Zach, Optics, Characterization, eLIGO OMC visibility vs. power measurement details
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I found that, in fact, I had lowered the modulation depth since when I measured it to be 0.45 rads --> Psb = 0.1.
Here is the sweep measurement:
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Wed Mar 20 09:38:02 2013, Zach, Optics, Characterization, [LLO] OMC test bench modified
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For various reasons, I had to switch NPROs (from the LightWave 126 to the Innolight Prometheus).
I installed the laser, realigned the polarization and modulation
optics, and then began launching the beam into the fiber, though I have not coupled any light yet. |
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Thu Mar 28 03:37:07 2013, Zach, Optics, Configuration, Test setup input optics progress
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[Lisa, Zach]
Last night (Tuesday), I finished setting up and aligning most of the input optics for the OMC characterization setup. See the diagram below, but
the setup consists of: |
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Fri Mar 29 08:55:00 2013, Zach, Optics, Configuration, Beam launched into fiber
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Quote:
Lisa and I concurred that it felt like we had converged to the optimum alignment and polarization, which would mean that the lack of |
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Thu Apr 4 00:35:42 2013, Zach, Optics, Configuration, MMT installed on breadboard, periscope built
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[Koji, Zach]
We installed the MMT that matches the fiber output to the
OMC on a 6"x12" breadboard. We did this so that we can switch from the "fauxMC" (OMC mirrors arranged with standard |
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Fri Apr 5 18:18:36 2013, Zach, Optics, Configuration, AOM probably broken
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Quote:
Then, I started to check the AOM path. I noticed that the 1st (or -1st) order beam is very weak. |
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Wed Apr 10 00:40:30 2013, Zach, Optics, Configuration, fauxMC locked
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[Koji, Zach]
Tonight, we locked the "fauxMC". We obtained
a visibility of >99%. |
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Wed Jun 5 01:06:35 2013, Zach, General, Characterization, L1 OMC as-built diagram
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D1300507
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Thu Jun 13 12:12:20 2013, Zach, General, General, [LLO] OMC and OMCS in LVEA
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https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=7395
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Thu May 3 21:45:58 2018, awade, General, Loan / Lending, Borrowed toaster oven
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| I’ve borrowed the black and decker toaster oven to dry some sonicated parts. It is temporarly located in the QIL lab. |
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Tue Nov 24 10:45:07 2020, gautam, Electronics, Characterization, The dark noise of the Q3000 QPDs
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I see that these measurements are done out to 100 kHz - I guess there is no reason to suspect anything at 55 MHz which is where this QPD will be reading
out photocurrent given the low frequency behavior looks fine? The broad feature at ~80 kHz is the usual SR785 feature I guess, IIRC it's got to do
with the display scanning rate. |
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Tue Oct 16 14:50:54 2012, jamie, jeff, General, General, OMC breadboard/plate measurement dimensions
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We have measured the dimensions and mass of the OMC glass plates/breadboards:
S/N
Mass (g)
Length
(mm)
Width (mm)
Height (mm)
Notes
01
6146
449.66
149.85
41.42, |
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Sat Jul 29 18:44:38 2017, rana, Electronics, Characterization, PDH amp
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| attachment 6: DCPD preamp looks like the opamp is wired for positive feedback? |
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Mon Sep 28 16:03:13 2020, rana, General, General, OMC Beam Dump Production Cure Bake
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are there any measurements of the BRDF of these things? I'm curious how much light is backscattered into the incoming beam and how much goes
out into the world.
Maybe we can take some camera images of the cleaned ones or send 1-2 samples to Josh. No urgency, just curiosity. |
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Fri Aug 23 11:11:44 2019, shruti, Optics, Characterization, Finding the curvature bottom
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I attempted to fit the data taken by Koji of the beam spot precession at the CCD in order to find the location of the curvature bottom in terms
of its distance (d) and angle () from the centre of the mirror. This was done using
the method described in a previous similar measurement and Section 2.1.3 of |
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Thu Aug 29 11:51:49 2019, shruti, Optics, Characterization, Wedging of the debonded PZTs - Calculation
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Using the measurements of PZTs 12,13 taken by Stephen, I estimated the wedging angle and orientation following Section 2.3.1 of T1500060. The results
can be found in Attachment1 and is summarised as follows.
For PZT 12, PZT 13 respectively: |
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Thu Sep 5 15:40:42 2019, shruti, Optics, Configuration, PZT Sub-Assembly
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Aim: To find the combinations of mounting prism+PZT+curved mirror to build two PZT sub-assemblies that best minimises the total vertical beam
deviation.
(In short, attachment 1 shows the two chosen sets of components and the configuration according which they must be bonded
to minimize the total vertical angular deviation.) |