I have to blame Jamie for putting extra 2 randomly.
Measured PRM-PR2 cavity finesse was actually 108 +/- 3 (even if you use digital system to get data).
Lorentzian fit:
Lorentzian function is;
f(x;x0,gamma,A) = A * gamma**2/((x-x0)**2+gamma**2)
where x0 is the location of the peak, gamma is HWHM, and A is the peak height.
Lorentzian fitting function in my original code (/users/yuta/scripts/modescanresults/analyzemodescan.py) was
fitFunc = lambda p,x,m: (m-p[2])*p[0]**4/(4*(x-p[1])**2+p[0]**4)+p[2]
In this function, p[0] is sqrt(FWHM), not sqrt(HWHM). I doubled gamma to make it FWHM and squared it because they should be positive.
During Jamie's modification of my code, he doubled p[0]**2 to get FWHM, which is wrong (/users/jrollins/modescan/modescan.py).
I should have commented that p[0] is sqrt(FWHM).
Redoing the analysis:
1. I pulled 2 out, and modified Jamie's modescan.py so that you can name each peak with peakdistinguish=True option. I also modified fitpeak function so that it throws away "peaks" which don't look like a peak.
2. If you run /users/yuta/PRCmodescan/run.py and name each peak, you will get peaks.csv which includes peak position, FWHM, and the type of the peak;
0.065017,0.001458,l
0.070446,0.001463,3
0.075940,0.001509,2
0.081552,0.001526,1
0.087273,0.001565,0
0.112027,0.001911,u
0.278660,0.002211,u
0.306486,0.001658,0
0.312480,0.001576,1
0.313626,2.507910,
0.318486,0.001626,2
0.319730,2.633097,
0.324801,0.001739,3
0.331848,0.001922,l
0.527509,0.001603,l
0.533231,0.001445,3
0.538648,0.001488,2
0.544081,0.001455,1
0.549517,0.001498,0
0.551725,2.422759,
0.570972,0.001346,u
3. /users/yuta/PRCmodescan/calcmodescanresults.py reads peaks.csv and tells you the results;
Time between TEM00 and sideband 0.0239435 pm 0.00115999887452 sec
Calibration factor is 462.167602898 pm 22.3907907867 MHz/sec
FSR is 78.4797010471 MHz
FWHM is 0.729828720682 pm 0.0174145743828 MHz
TMS is 2.64718671684 pm 0.0538858477824 MHz
Finesse is 107.53166986 pm 2.5658325169
Cavity g-factor is 0.994390582331 pm 0.000228155661075
Cavity g-factor is 0.988812630228 pm 0.000453751681357 (Edited by YM; see elog #8056)
RoC of PR2 is -187.384503001 pm 4.26100999578 m (assuming PRM RoC= 122.1 m)
RoC of PRM is 217.915890722 pm 5.65451518991 m (assuming PR2 RoC= -600 m) |