40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log  Not logged in ELOG logo
Message ID: 10130     Entry time: Sat Jul 5 04:18:45 2014
Author: Andres 
Type: Update 
Category: 40m Xend Table upgrade 
Subject: Adding Two Lenses After the Second Steering Mirror in Order Two Increase the Gouy Phase Difference Between the Sterring Mirrors 

I had been working on the Xend table optical layout update. Since the two steering mirrors in the Xend green are too close to each, there is a very small Gouy Phase different between these two mirrors. It was suggested to place two lenses so that we can increase the Gouy Phase. I have been working with Nick on this problem, and we had found a solution by using a la mode. We had written an a la mode code that optimize the Gouy Phase and the Mode Matching at the same time. After trying different lenses, we found the following results: a mode matching of 0.9939 as it is show in the first attachment below, and we found a Gouy Phase different between the two mirrors of about 60 degrees. I took photos of the Xend Table. The first photo is the Xend table as we had it right now. In the second photo, I moved the 2nd lens, and I placed the two more lenses that we need it, with more or lenses the correct position where they will be placed. The three old lenses will be replaced by three lenses of different focal length as it can be seen in the first attachment below. The first lens and third lens will stay in the same position where the old first lens and old third lens are, and the second lens will be moved by about half of an inch. We might have one or two of the lenses that we need, but we will have to order the rest of the lenses that need. My plan is to verify the lenses that we already have. Then, I need to let Nick know with lenses we need to order. Hopefully, we will be able to update the table by the end of this week if everything turn out fine.

Attachment 1: OverlapAndComponentsOfTheSolution.png  35 kB  | Hide | Hide all | Show all
OverlapAndComponentsOfTheSolution.png
Attachment 2: CloseLookToTheGouyPhaseBetweenMirr1AndMirr2.jpg  102 kB  | Show | Hide all | Show all
Attachment 3: EntireRangeOfBeamPath.jpg  100 kB  | Show | Hide all | Show all
Attachment 4: XendTableWithTwoNeedLensesAdding.JPG  9.106 MB  | Hide | Hide all | Show all
XendTableWithTwoNeedLensesAdding.JPG
Attachment 5: SchematicOfSolutionForTheLensesGouyPhase.jpeg  150 kB  | Hide | Hide all | Show all
SchematicOfSolutionForTheLensesGouyPhase.jpeg
Attachment 6: XendGreenModeMatchingAndGouyPhaseOptimization.m  5 kB  | Hide | Hide all | Show all
clear all
% In this code we are using a la mode to optimatize the mode matching and
% to optimatize the Gouy phase between mirror 1 and mirror 2. All the units
% are in meter

w0=2.943*1e-5; % The Waist of the laser measured before the faraday
z0_laser=-0.039; % position measured where the waist is located 
lamb= 532*10^-9; % wavelength of green light in mm
lFaraday=.0638; % Length of the faraday

... 148 more lines ...
Attachment 7: BeforeIncludingLensesORMovingLenses.JPG  7.960 MB  Uploaded Mon Jul 7 10:26:40 2014  | Hide | Hide all | Show all
BeforeIncludingLensesORMovingLenses.JPG
ELOG V3.1.3-