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Thu May 8 01:50:25 2008
Arm Cavity HOM Resonances
Nothing new, but I calculated the frequencies of the first 22 higher order transverse modes and thought I might as well list them here.
To do this I took formula (23) from page 762 of Siegmans book and put it into this form:
f_fsr dfmn = ----- * (m+n) * acos(sqrt(g1*g2)) pi
and then calculated them from m+n = 1..22 (22 is not a magic number).
I also used the 'mod' function of matlab to calculate the frequency mod FSR so that we would know how far away
from a cavity resonance it is. I took as parameters: Larm = 38.55 m, Ritm = 1e6 m, Retm = 57.1 m. Kirk measured
the arm length some time ago; we need to measure the arm g-factor...maybe we'll put Tobin on this when he comes
by for a visit.
1.1936 (TEM01, TEM10)
(TEM22, TEM13, TEM31)