40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log  Not logged in ELOG logo
Message ID: 4307     Entry time: Wed Feb 16 10:35:40 2011
Author: Larisa Thorne 
Type: Update 
Category: IOO 
Subject: WFS quantum efficiency as a function of angle 

 Here is the followup on Jenne's February 14th, 2011 update on the quantum efficiency measurements of WFS2.

http://nodus.ligo.caltech.edu:8080/40m/4289

 

Attached is a PDF of my calculations, based on measurements ranging between 0-25 degrees in 5 degree increments.

The graph at the bottom plots these angles versus the calculated quantum efficiency at each point and the responsivity. Since quantum efficiency and responsivity only differ by a factor of some natural constants (lamda, e, h, c), I used a graph with two vertical axes, because the points would be plotted at essentially the same location if quantum efficiency (%)  and responsivity (Amps/Watts) were graphed on two separate plots.

The calculated values for quantum efficiency based on my measurements (labelled "ExpAverage") were pretty close to what Jenne had calculated in earlier attempts, which was around 60%. Just to test, I compared my quantum efficiency result against the calculation of quantum efficiency using the responsivity value for silicon, 0.5 Amps/Watt, which is labelled as "Spec". Comparison of "ExpAverage" and "Spec" shows that they differ by only about 2%, so I conclude that the theoretical quantum efficiency calculated using a given responsivity agrees with my measurement-based experimental result.

Attachment 1: QEcalcs.pdf  74 kB  | Show | Show all
ELOG V3.1.3-