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ID Date Authorup Type Category Subject Text Attachments
  1269   Wed Jul 31 00:31:39 2013 taraNotesopticcoating optimization for AlGaAsThe codes for optimizing Thermo-optic noise
in coatings are up on svn.
I adopt some codes that have been
  1274   Thu Aug 1 21:19:57 2013 taraDailyProgressBEATsearching for beatI locked both cavities and trying to search
for the beat signal, I have not succeeded
  1275   Fri Aug 2 12:18:16 2013 taraDailyProgressBEATsearching for beatFound the beat @ 116 MHz. RCAV SLOW =5.762V,
ACAV SLOW = 1.209 V. 
  1276   Fri Aug 2 12:38:41 2013 taraDailyProgressfiber opticinsulating foamI turned off the hepa fans over the table
over the night. I came back this morning
and the temperature (measured on the vacuum
  1290   Fri Aug 9 16:00:14 2013 taraNotesNoiseBudgetnoise huntingI measured the slope of the error signal
for ACAV path to be 200 kHz/V. This will
  1291   Fri Aug 9 17:58:01 2013 taraNotesopticcoating optimization for AlGaAsBetter TO optimized coatings calculation
is done. Now the Transmission, phase reflection,
and TO noise are optimized.
  1293   Sat Aug 10 00:49:20 2013 taraNotesNoiseBudgetThermo-refractive noise in substrateI wrote a code to calculate thermo-refractive
noise in a finite-sized cylindrical substrate
as given in Heinert etal 2011. The noise
  1298   Tue Aug 13 21:45:51 2013 taraDailyProgressNoiseBudgetTransfer Functions (RIN to Frequency noise via photothermal)I rechecked the TF between power fluctuation
and frequency noise in beat measurement that
I did last year. The estimated result agrees
  1300   Fri Aug 16 04:35:58 2013 taraDailyProgressNoiseBudgetTransfer Functions (RIN to Frequency noise via photothermal)I estimated the requirement for laser RIN
for AlGaAs coatings. The result is a factor
of 5 more stringent from what we need for
  1305   Fri Aug 16 22:05:27 2013 taraDailyProgressBEATnoise hunting Noise hunting is in progress, I checked
the error noise from ACAV and RCAV loops
and compared them to the beat. The beat is
  1307   Tue Aug 20 20:10:01 2013 taraDailyProgressBEATnoise huntingNoise hunting is in progress. Today I identified
that scattered light from the window is one
of the problem.
  1309   Thu Aug 22 00:29:32 2013 taraDailyProgressNoiseBudgetinstalled EOAMI installed an electro-optic amplitude
modulator (EOAM) in RCAV path. Better optimization
will be needed to reduce extra noise.
  1310   Thu Aug 22 13:36:19 2013 taraDailyProgressNoiseBudgetTransfer Functions (RIN to Frequency noise via photothermal) I went through all the code with
Evan and found another mistake. This time
the code should be correct, and the result
  1311   Thu Aug 22 20:31:28 2013 taraDailyProgressNoiseBudgetinstalled EOAMThe bump at 2kHz in the beat signal that
I saw before was also from RFAM. By adjusting
the 1/2 waveplate in front of the sideband
  1313   Sat Aug 24 15:42:54 2013 taraDailyProgressVacuumpumping down the chamberI closed the chamber. The turbo pump is
on and pumping down.
 I realigned the beams so the
  1315   Tue Aug 27 16:11:26 2013 taraNotesopticcoating optimization for AlGaAs:error analysisSince the optimized layer structure is
designed, I'm checking how the coatings properties
change with error in layer thickness.
  1317   Wed Aug 28 20:19:44 2013 taraNotesEOMEOM driver: modificationWe modified the EOM driver, so that the
resonant frequency is now~ 14.75MHz. The
full test will be done later.
  1318   Wed Aug 28 21:21:38 2013 taraNotesopticGWINC for TO calculation: recapHere is a summary for how I verify the
codes for TO calculation.
So far, we have been using a set
  1319   Thu Aug 29 13:25:49 2013 taraDailyProgressVacuumpumping down the chamberThe turbo pump is removed, and the ion
pump is on. The initial value is ~7mA.
I removed the turbo pump and turn
  1320   Sun Sep 1 18:38:37 2013 taraNotesopticcoating optimization for AlGaAs:error analysisI updated the optimization and error analysis.
The error in optimized structure is comparable
to that of a standard quarter wave length
  1321   Mon Sep 2 03:38:27 2013 taraDailyProgressNoiseBudgetbeatIt's a quiet night, so I went down the
lab to measure the beat signal. We are getting
close. I think I have to review my noise
  1322   Mon Sep 2 18:31:46 2013 taraNotesopticcoating optimization for AlGaAs:error analysisCoating optimization and error analysis
are updated, see PSL:1320.
  1327   Sat Sep 7 04:29:32 2013 taraDailyProgressNoiseBudgetbeatShort note from tonight measurement:
1) scattered bump from dc to 100Hz
is mostly from seismic. It is worse during
  1329   Mon Sep 9 02:27:46 2013 taraDailyProgressNoiseBudgetRIN induced TO noise in beatThe measured RIN is measured and converted
to frequency noise via photo thermal effect
then compared to beat. The effect seems to
  1331   Mon Sep 9 21:19:24 2013 taraDailyProgressNoiseBudgetRIN induced TO noise in beatI'm trying to understand the measured RIN
in the setup. The evidence suggests that
the measured RIN in 100Hz- 6kHz, is real
  1332   Tue Sep 10 04:53:34 2013 taraDailyProgressNoiseBudgetRIN induced TO noise in beatThe cause of the peaks around 1kHz in RIN
is solved, PMC is the reason. After damping
it, the peaks disappears.
  1338   Tue Sep 17 19:43:45 2013 taraSummaryNoiseBudgetCoating Thermal Noise Calculator


  1340   Wed Sep 18 21:55:11 2013 taraNotesopticcoating optimization for AlGaAs:error analysis 
Optimized coatings structure.
  1342   Thu Sep 19 14:55:11 2013 taraSummaryNoiseBudgetCoating Thermal Noise Calculator


  1343   Thu Sep 19 18:09:18 2013 taraSummaryNoiseBudgetCoating Thermal Noise Calculator


  1344   Thu Sep 19 20:38:17 2013 taraNotesopticcoating optimization for AlGaAs:error analysisDetails for AlGaAs coatings order

structure can be found in 
  1345   Fri Sep 20 19:26:45 2013 taraNotesopticcoating optimization for AlGaAs:error analysisI'm using Matt's code to do error analysis
for AlGaAs coatings. This time I vary materials'
parameters and compare the thermo optic noise,
  1351   Mon Sep 23 18:50:05 2013 taraNotesopticcoating optimization for AlGaAs:error analysis

  1356   Thu Sep 26 23:25:40 2013 taraNotesopticcoating optimization for AlGaAs:error analysis I'm trying to find another optimization
that is less sensitive to change in nH and
nL. Here is a few thought and a few examples.
  1359   Thu Oct 3 10:34:32 2013 taraNotesopticcoating optimization for AlGaAs:error analysis The new optimization is less sensitive
to the values of refractive indices, but
the overall error will not change much if
  1360   Mon Oct 7 19:53:53 2013 taraDailyProgressSeismicnew table legs installedNew legs were installed.  The table
is floated. The cables for signals/ power
supplies will be reconnected later
  1363   Thu Oct 10 01:59:24 2013 taraNotesopticcoating optimization for AlGaAs:error analysis I recalculated the coatings properties,
with the values of nH and nL to be 3.48 and
2.977. Note about each optimization is included
  1365   Fri Oct 11 15:23:54 2013 taraNotesopticcoating optimization for AlGaAs:electric field in coating layerElectric field in coating layer is calculated.
This will be used in loss calculation in
AlGaAs coatings.
  1367   Mon Oct 14 21:02:00 2013 taraNotesopticcoating optimization for AlGaAs:variation in xI checked the dependent of coatings properties
with the uncertainty in x (amount of Al in
Al_x Ga_(1-x) As). 
  1370   Tue Oct 22 04:34:12 2013 taraDailyProgressSeismicnew table legs installedAfter installing the table legs, I have
been trying to measure the beat. However,
there is an unknown scattered light noise
  1374   Sun Oct 27 20:12:25 2013 taraNotesoptic photothermal noise in AlGaAsI revised the calculation for photo-thermal
noise in AlGaAs coatings, the photo thermal
noise should not be a limiting source.
  1376   Wed Oct 30 01:56:38 2013 taraDailyProgressoptictable workI'm optimizing the setup, and clearing
the table a little bit.

    Self homodyne setup in
  1377   Thu Oct 31 00:02:17 2013 taraDailyProgressElectronics EquipmentTTFSSEvan found that when common gain is changed,
DC offset also changes as well. I'm still
looking into the problem.
  1379   Fri Nov 1 00:22:40 2013 taraDailyProgressopticmore optimizationI'm putting EOAM back on ACAV path. The
setup is roughly optimized.
(14.75 MHz) EOM , EOAM, quarter waveplate
  1381   Tue Nov 5 01:11:15 2013 taraDailyProgressElectronics EquipmentTTFSS


  1383   Wed Nov 6 01:14:58 2013 taraDailyProgressElectronics EquipmentTTFSSWe made a mistake by choosing the input
power to the cavities to be 0.25 mW, so today
I turned them back to 1mW and measure the
  1384   Thu Nov 7 05:08:13 2013 taraDailyProgressNoiseBudgetphotothermal noise in SiO2/Ta2O5I add the photo thermal noise effect in
the noise budget. With ISS, photothermal
noise should be sufficiently small.
  1385   Fri Nov 8 03:36:44 2013 taraDailyProgressopticredo- PMC pathI'm re-arranging the optics in PMC path
a bit. The work is in progress, so ACAV path
is still down.
  1386   Mon Nov 11 19:37:13 2013 taraDailyProgressopticredo- PMC pathPMC path is back, I aligned the polarization
of the input beam to the BB EOM for TTFSS.
The visibility of PMC is now ~ 80%.
  1387   Tue Nov 12 15:27:32 2013 taraNotesDocumentationthesis on ctnI created an svn folder for my thesis on
CTN measurement.
It can be found here
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