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Entry  Wed Jan 16 18:08:06 2013, Jenne, Update, Locking, Expected PRC gains 
    Reply  Wed Jan 16 20:27:16 2013, rana, Update, Locking, Expected PRC gains 
       Reply  Thu Jan 17 00:17:31 2013, Jenne, Update, Locking, Expected PRC gains 
          Reply  Wed Jan 23 18:16:11 2013, Manasa, Update, General, Laseroptik mirror - SN6 sn6_trans.png
             Reply  Wed Jan 23 20:24:05 2013, Koji, Update, General, Laseroptik mirror - SN6 
                Reply  Wed Jan 23 22:02:25 2013, Manasa, Update, General, Laseroptik mirror - SN6 
                   Reply  Thu Jan 24 15:16:50 2013, Manasa, Update, General, Laseroptik mirror - SN6 sn6_trans1.png
                      Reply  Thu Jan 24 16:23:24 2013, Koji, Update, General, Laseroptik mirror - SN6 
                         Reply  Tue Jan 29 14:20:02 2013, Koji, Update, General, Finer rotation stage for optics characterization 
                      Reply  Thu Jan 24 16:34:56 2013, rana, Update, General, Laseroptik mirror - SN6 
                      Reply  Fri Jan 25 08:10:42 2013, Steve, Update, General, Laseroptik mirrors 
                         Reply  Mon Jan 28 19:07:45 2013, Manasa, Update, General, SN6 Laseroptik mirror - Tranmittance measurements sn6_trans0128.pngtrans_layout.png
Message ID: 7905     Entry time: Wed Jan 16 18:08:06 2013     Reply to this: 7909
Author: Jenne 
Type: Update 
Category: Locking 
Subject: Expected PRC gains 

I was calculating the power recycling gains we expect for different versions of the PRC, and I am a little concerned that we aren't going to have much gain with the new LaserOptik mirrors.

I'm using

                       t_PRM^2

G =  -------------------------------------------

       (1 - r_PRM * r_PR2 * r_PR3 * r_end)^2

 

from eqn 11.20 in Siegman.

r_end is either the ITM (for a symmetric Michelson) or the flat mirror that we'll put in (for the PR-flat test case).

r = sqrt( R ) = sqrt( 1 - T ) for mirrors whose power transmission is the quoted value.

 

Some values: 

t_PRM^2 = T_PRM = 0.055   --------->   r_PRM = sqrt( 1 - 0.055 )

T_G&H = 20e-6   ---->   r_G&H = sqrt( 1 - 20e-6 )

T_LaserOptic = 0.015 (see elog 7624 where Raji measured this...1.5% was the best that she measured for P polarization.  Elog 7644 has more data, with 3.1% for 40deg AoI) -------> r_LasOpt = sqrt( 1 - 0.015 ) or sqrt( 1 - 0.031)

T_ITM = 0.014 -----------> r_ITM = sqrt( 1 - 0.014 )

 

Some calculations with 1.5% LaserOptik transmission:

G_PRC_2G&H = 45

G_PRC_G&H_LasOpt = 31

G_PRM_flatG&H = 51

With the 3% LaserOptik transmission:

G_PRC_G&H_LasOpt = 22

G_PRM_flatG&H = 30

More ideal case of just PRM, flat mirror (either ITM or G&H), ignoring the folding mirrors:

G_PRM_ITM = 45

G_PRM_flatG&H = 70

 

Punchline:

If the LaserOptik mirror has 1.5% transmission at ~45 degrees, the regular PRC expected gain goes down to 31, from 45 with both folding mirrors as G&Hs.

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