New Mode Matching Telescope for Upgrade 2009-2010
The installation of a new mode matching telescope (MMT) has been performed in order to inject a right beam mode into the main interferometer. This change is due to the change of the recycling cavity length. The MMT was installed after the MC and the Faraday Isolator inside of the vacuum chambers. And the MMT consists of two curved mirrors; a concave mirror and a convex mirror. This page explains how it was designed and installed.
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Installation of MMT
Mode Scan Measurement: After Mode Cleaner
- Here is the plot with the ideal mode of the mode cleaner shown in brown. The ideal mode was plotted with the radius of curvature of 18.4. The blue curve is the fit to the vertical beam radius, the purple curve is the fit to the horizontal beam radius, * denotes a data point from the vertical data, and + denotes a data point from the horizontal data.
- attachment:newIOO_afterMC.png
- attachment:mcerrors.png
waist for vertical mode [mm] |
w0_v |
1.59 ± 0.01 |
waist for horizontal mode [mm] |
w0_h |
1.51 ± 0.01 |
waist position for vertical mode [m] |
z_v |
673 ± 28 |
waist position for horizontal mode [m] |
z_h |
1 ± 29 |
Mode Scan Measurement: After MMT2
- The plot below was taken after the MMT.
![MMT20100618.png]](/Input_Optics?action=AttachFile&do=get&target=MMT20100618.png "MMT20100618.png]")
waist for vertical mode [mm] |
w0_v |
2.81183 +/- 7.793e-03 |
waist for horizontal mode [mm] |
w0_h |
2.9089 +/- 1.998e-02 |
waist position for vertical mode [m] |
z_v |
5.35487 +/- 0.2244 |
waist position for horizontal mode [m] |
z_h |
1.95931 +/- 0.4151 |
- All the distances are calibrated from the position of MMT2 i.e. the position of MMT2 is set to be zero.
Resultant Mode Overlap
- The resultant mode overlap was calculated to 99.3%
![MMT20100618.png]](/Input_Optics?action=AttachFile&do=get&target=newIOO_overlap.png "MMT20100618.png]")
Design of MMT
- The scripts here find the optimal Mode Matching options for the upgraded 40m Mode Matching Telescope.The scripts are in the 40m SVN:
[https://nodus.ligo.caltech.edu:30889/svn/trunk/docs/jenne/ModeMatchingTelescope/ /trunk/docs/jenne/ModeMatchingTelescope/]
- The main script is MMTmodematching.m It utilizes many of the other scripts in the folder.
- The MMT is now finalized, and Koji is going to finish placing the MM optics on the table layout according to these numbers. A summary has been written up and put in the same SVN folder, and is linked here: [attachment:MMT_summary.pdf MMT Summary]. Table 2 from the document lists the final distances between each optic:
attachment:MMT_summary_FinalDistances.png
Links
to the 40m elog
[http://nodus.ligo.caltech.edu:8080/40m/3088 Mode scan measurement after MMT2 (take 2) and the resultant overlap ]
[http://nodus.ligo.caltech.edu:8080/40m/3077 Preliminary mode overlap results]
[http://nodus.ligo.caltech.edu:8080/40m/3076 Mode scan measurement after MMT2 (take 1) ]
[http://nodus.ligo.caltech.edu:8080/40m/3068 Mode scan measurement after MMT1 (take 2) ]
[http://nodus.ligo.caltech.edu:8080/40m/3029 Mode scan measurement after MMT1 (take 1) ]
[http://nodus.ligo.caltech.edu:8080/40m/2986 Mode scan measurement after the MC]
[http://nodus.ligo.caltech.edu:8080/40m/3054 Notes about beam shape ]
to the wiki page
OLD (2001) Input Optics Description
- Mike Smith's document on the 40m optics in general.