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ATF eLog 
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Message ID: 164
Entry time: Thu Jul 9 02:24:07 2009
In reply to: 163

Author: 
rana 
Type: 
Laser 
Category: 
PSL 
Subject: 
Mode Matching and the PMC 


The Anderson formulas are sort of OK in this regime but should only be used to estimate the mismatch.
Of course, its easy just to do the overlap integral and get the exact number. Its of limited use, since
the cavity will often not lock at the right point of the mismatch is so big.
Another possible method is to turn the power way down (less than 1 mW) and then scan it and fit
for the modes in transmission. The low power is to avoid thermal selflocking distortion of the fringe.
One can use knowledge of the PZT coefficient and the wavelength of the laser and modulation frequencies
to determine the cavity's gfactors and therefore the waist sizes. The cavity gfactor is defined as
g = 1  L/R. 