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New entries since:Wed Dec 31 16:00:00 1969
ID Date Author Typedown Category Subject Text Attachments
  1   Wed Jul 11 23:01:01 2012 janoschOpticsCharacterizationstarting the multi-color scatter experimentSteve Maloney, a visiting highschool teacher,
and I have started to set up a new scattering
experiment in the Richter lab. The idea is
  2   Fri Jul 13 10:34:35 2012 janoschOpticsCharacterizationcamera imageWe were confused a bit about how the camera
image changes when you move the arm that
holds the camera and lens around the
  3   Fri Jul 13 20:53:35 2012 janoschOpticsCharacterizationtwo imagesThe following two pictures were taken from
the same angle with green (left) and red
(right) incident laser at an angle of 15deg
  4   Tue Jul 17 18:32:11 2012 janoschOpticsCharacterizationpurple imagesWe have the new 405nm laser pointer. 
The image to the left shows the scattered
light from the red laser, the image to the
  5   Wed Jul 18 18:43:34 2012 janoschOpticsCharacterizationgone with the windHere a little purple video. It starts with
scattering angle around 15deg and stops at
about 80deg. 
  6   Fri Jul 20 18:35:42 2012 janoschOpticsCharacterizationpurple improvements and first uncalibrated BSDF curvesToday we improved alignment of the lens-camera
arm. We discovered earlier that this alignment
affects the amount of "snowfall"
  7   Tue Jul 24 10:59:59 2012 janoschOpticsCharacterizationsum of purple and redWe played around with Matlab today. The
first step was to convert light wavelengths
into RGB colors. In this way we can combine
  8   Fri Oct 12 16:23:20 2012 janoschOpticsDaily Progressreassembled setupNothing has happened since Steve, the visiting
highschool teacher, has left. Meanwhile,
some parts of the multi-color BRDF setup
  16   Fri May 20 15:18:58 2016 GabrieleOpticsDesignOptical levers layoutAttached 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
  17   Sun May 22 23:40:45 2016 GabrieleOpticsDesignOptical levers layoutAn improved design is attached. I modified
the input telescope to avoid using shor focal
length lenses, to make it less critical,
  23   Thu Jun 16 00:47:42 2016 GabrieleOpticsDaily ProgressQuality factor measurement of a Mark Optics disk at LMA[Massimo Granata (LMA), Quentin Cassar
(LMA), Gabriele] 

This week I'm visiting LMA
  51   Mon Jul 18 18:05:46 2016 GabrieleOpticsDaily ProgressOptical setupSmall modifications to the optical setup:

added a 1m focal lenght
lens (AR coated for 1064nm...) right before
  60   Mon Jul 25 15:35:31 2016 GabrieleOpticsCharacterizationCalibration of the QPD in physical unitsThe
equations below are wrong. Please refer to https://nodus.ligo.caltech.edu:8081/CRIME_Lab/116
  91   Fri Aug 19 19:05:01 2016 GabrieleOpticsDaily ProgressDisk installed into the chamberI assembled the disk suspension sytem and
installed into the chamber. Although I don't
have the magnets and coils, I installed the
  95   Sun Aug 21 13:45:56 2016 GabrieleOpticsDaily ProgressWierd behavior of ring downs and Improved setupThe last two ring downs I measured today
showed a weird behavior of the lowest modes:

  101   Mon Aug 22 16:59:13 2016 Gabriele, AlastairOpticsDaily ProgressLaser polishing of the disk edgesWe set up a test facility for laser polishing
the disk edges, using the CO2 laser in the
TCS laboratory. We focused the beam with
  105   Thu Sep 1 02:13:33 2016 GabrieleOpticsCharacterizationExpected frequencies for the 75 mm disks with flatsHere are the nominal parameters of the
disk with flats

  116   Tue Sep 20 15:34:00 2016 GabrieleOpticsDaily ProgressImproved optical lever layoutGoal

Improve the optical setup,
by increasing the response of the QPD to
disk motion.
  122   Thu Sep 22 13:39:40 2016 GabrieleOpticsConfigurationUpdated design for the new C.Ri.Me. setupToday I measured the amount of space available
on the table for the new (4-fold) C.Ri.Me.
setup. It's 1050 x 1220 mm, with the
  127   Mon Sep 26 15:59:09 2016 GabrieleOpticsDaily ProgressQPD auto centeringWe have a few motorized mounts (with New
Focus picomotors) and one controller (an
old New Focus 8753, six axis total) that
  132   Thu Sep 29 15:40:45 2016 GabrieleOpticsDesignBeam profile of new 21mW HeNe laser and tweak of optical lever designI measured the beam profile of the new
Thorlabs HeNe (21.8 mW measured). The beam
waist is 355 microns, very close to the laser
  270   Fri Jan 20 17:20:20 2017 GabrieleOpticsDaily ProgressInput part of the optical lever setup installed and alignedToday I installed and aligned part of the
optical components for the optical lever
of the new setup. For the moment being I
  272   Mon Jan 23 16:29:52 2017 GabrieleOpticsDaily ProgressInput part of the optical lever setup installed and alignedToday I cabled and installed the four QPD,
in a temporary position. I also assembled
four picomotor mounts that will be used for
  280   Fri Jan 27 14:56:55 2017 GabrieleOpticsDaily ProgressOptical lever setup completedThe four optical levers are completely
installed and aligned to a horizontal reference.

  287   Wed Feb 1 15:23:42 2017 GabrieleOpticsNoise huntingWandering line is due to the laserThe wandering line I mentioned in my previous
elog, which is spoiling most of the sensitivity,
turns out to be power noise of the laser. 
  291   Mon Feb 6 11:19:13 2017 GabrieleOpticsDaily ProgressLaser swapThe Thorlabs laser has been misbehaving
for the whole weekend. Even after many days
being continuosly on, the wandering line
  295   Tue Feb 7 16:16:37 2017 GabrieleOpticsDaily ProgressLasersThe high power lasers I tested so far (the
Thorlabs 21mW and the JDSU 1125P) are noisy:
they both have wandering lines that from
  296   Wed Feb 8 17:01:01 2017 GabrieleOpticsDaily ProgressTwo laser installed, setup alignedToday I swapped out the 8mW laser
and installed two 2.5 mW lasers. I rebuilt
the input part of the optical levers and
  300   Thu Feb 9 09:30:52 2017 GabrieleOpticsDaily ProgressTwo laser installed, setup alignedThe lasers are behaving well, there is
no high noise or wandering lines. The spectrum
below is taken in air: that explains the
  301   Thu Feb 9 11:35:27 2017 GabrieleOpticsConfigurationQPD calibration This morning I measured the beam profiles
at the QPD positions. As expected, the beams
are not gaussian there, since we are seeing
  311   Fri Feb 17 13:44:47 2017 GabrieleOpticsDaily ProgressSwapped picomotor and re-alignmentSince I had recurrent problems with the
picomotors used for QPD3, I swapped them
with another Newport motorized mirror that
  331   Fri Mar 10 16:44:13 2017 GabrieleOpticsDaily ProgressUpdated in vacuum periscope of CR0This afternoon I removed the old periscope
from CR0 and installed a new one with finely
adjustable mount, like those in the new chamber.
  336   Thu Mar 30 15:23:44 2017 GabrieleOpticsGeneralSwapped HeNe laser in CR0The JDSU HeNe laser 1103P that I was using
is dead. I swapped it with a JDSU 1125P borrowed
from the 40m.
  338   Fri Apr 7 16:19:03 2017 GabrieleOpticsDaily ProgressNew 1103P laser installedThis afternoon I installed the new Lumentum
(former JDSU) HeNe laser, model 1103P in
  454   Tue Jan 30 09:19:09 2018 GabrieleOpticsConfigurationSetup for 50mm disksI realigned all optical levers to measure
the 50mm disks. In brief, I moved the input
2" mirrors, the in-vacuum 2" mirrors
  459   Tue Feb 13 16:28:49 2018 GabrieleOpticsConfigurationSetup resigned for 75mm disks    
  479   Thu Mar 8 09:40:10 2018 GabrieleOpticsConfigurationRealigned all optical levers to horizontal reference    
  497   Tue Mar 27 16:36:49 2018 GabrieleOpticsConfigurationOptical levers re-aligned for 50mm substrates    
  658   Fri Apr 12 09:36:54 2019 GabrieleOpticsConfigurationRealignmentI realigned the entire CR1-4 setup

ensured that beam out of
the chamber are at 6" height everywhere.
  15   Thu May 19 11:36:04 2016 GabrieleMechanicsDesignA first design of the disk assemblyHere are some screenshots of the disk assembly
and a look at how four of them will sit into
the vacuum chamber. The Solidworks models
  19   Fri May 27 02:09:37 2016 GabrieleMechanicsCharacterizationLowest usable mode of fused silica disksI did some FEA simulation of fused silica
disks, to identify the lowest usable eigenmode.
By usable I mean a mode that has zero elastic
  76   Wed Aug 10 10:04:35 2016 GabrieleMechanicsDaily ProgressThe prototype of the disk retain system is hereYesterday we received the prototype of
the disk suspension and retain system. Everything
looks good. I checked that the disk fits
  124   Fri Sep 23 08:11:48 2016 GabrieleMechanicsDaily ProgressTest of the disk retaining ring motionIn brief, it doesn't work. The magnets
and coils are strong enough to push up the
ring with a sample inside, but the friction
  189   Tue Nov 15 10:35:11 2016 GabrieleMechanicsDaily ProgressParts for laser polishing setup are hereThe parts all fit as expected. They're
mounted on the stages.

  266   Thu Jan 19 14:16:53 2017 GabrieleMechanicsDesignNew concept for retaining ring motionSince my experiment with coil and magnets
didn't work out very well, here's
a new concept for the motion of the four
  284   Tue Jan 31 11:21:44 2017 GabrieleMechanicsDaily ProgressRetaining ring mechanicsAll parts for the motion of the retaining
rings have been received and are ok. We're
going to clean and bake them. 
  303   Fri Feb 10 17:16:28 2017 GabrieleMechanicsDaily ProgressTranslation stage to move retaining ringsThis afternoon I installed the picomotor
and the translation stage that will be used
to move the retaining rings up and down.
  304   Sat Feb 11 16:22:26 2017 GabrieleMechanicsDaily ProgressTranslation stage to move retaining ringsThe ring motion up and down was not very
smooth, again due to friction on the centering
  405   Thu Aug 10 13:36:08 2017 Gabriele, ZachMechanicsConfigurationESD moved closer to disk in CR0We first measured the distance of the ESD
from the disk in the test chamber (CR0).
We had to remove the retaining ring to have
  406   Fri Aug 11 09:22:21 2017 GabrieleMechanicsConfigurationESD moved closer to disk in CR0The plots below compare the SNR and peak
amplitude of all excited modes, in the new
and old configuration. The new confgiuration
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