LIGO Document T0900043-v3

Optical Layout and Parameters for the Advanced LIGO Cavities

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Document type:
T - Technical notes
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16 Mar 2012, 06:54
18 Oct 2010, 22:00
20 Oct 2009, 14:51
20 Aug 2009, 14:17
27 Jul 2009, 14:24
16 Jul 2009, 11:29
02 Apr 2009, 09:05
30 Mar 2009, 12:03
30 Mar 2009, 12:01
30 Mar 2009, 12:00
10 Feb 2009, 08:45
This document describes the optical parameters of the various cavities for Advanced LIGO. The lengths between various optical elements, ROC values of the mirrors, and their tolerances are listed. The various cavity parameters like Finesse, linewidths, and transversal mode spacing are calculated. Included also are the higher order modes offsets from resonances. The recycling cavity parameters are picked assuming that the TCS keeps the IFO same for both the cold as well as full power operation. The ROCs of the recycling cavity mirrors can be changed a little such that the recycling cavity matches the arm cavity mode at reduced power without engaging TCS.
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Notes and Changes:
Version 3: Here we have defined the RC parameters such that the values are optimized for low power (12.5 W) to have better mode matching both at the start as well as for 25 W operation. Table 3 has been added that reflects the values for low power operation.
the lengths are based upon Mike Smith's most recent Zemax model. The version 6 of reference 1 does not exist as of now but the values have been taken from EXCEL sheets that Mike maintains.

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