Today we measured the Mode Cleaner transmission.
To access to the MC finesse, we tried to use the following fit : T0/ ( 1 + 4R / (1-R)² * sin² ( pi (x-x0)/FSR ) ) + bg
Attached to this report are two results we could get : one without normalization, one with normalization.
By using Finesse = 4R / (1-R)², we could get the following results :
First case : 209
Second case (with normalization) : 360
By checking the ratio FSR over peak width : Finesse = 150.
We will try to undestand better how to fit this function