The cavity was realigned using irises instead of pinholes, gave a better alignment.
The inside of the box, the spherical and the injection mirror were cleaned and placed back inside the box.
we see beating of fundamental mode, previously at the transmission point we placed a wedge to split the beam which resulted in an elliptical mode
we removed it and placed a very thin beam splitter, the beam is circular now.
The cavity was locked in air at a coupling of ~ 60-70 %
Finesse and line width measured five readings with a Finesse average 25095.08884 of a Gain ~ 8000
FWHM (KHz) = 8.2928
Finesse = 25323.0544
FWHM (KHz) = 7.9202
Finesse = 26514.4395
FWHM (KHz) = 8.5834
Finesse = 24465.8636
FWHM (KHz) = 8.4571
Finesse = 24831.2419
FWHM (KHz) = 8.6275
Finesse = 24340.8448
Theoretical and expected Finesse for the 2 mirror setup with the losses is calculated by Ronic for comparison between four and 2 mirror setup.
| Manar Amer wrote: |
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The SBox cavity setup was changed to have only 2 mirrors M1 plane and M2 spherical, both from ThomX
Distance between the mirror ~ 72 cm , increased from 70 cm to take into account the thickness of the ThomX mirrors
Two lenses (300 mm @ 50 cm , 200 @ 104 cm) were placed to have the beam radius ~ 0.55 mm.
The cavity was locked with a coupling of 60 %, for Finesse measurement the sweep was taken over 100 KHz of 2 seconds.
FSR ~ 210.00 MHz, line width ~ 8.56 KHz, Finesse ~ 24 500 .
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