How much LO power can we handle on the CCD?
In [46]:
photon_eV = 1240/780.0
photon_J = photon_eV / 6.24150934E18
exposure_time = 20e-6
pixels_hit = 200*200
saturation_count = 2**16
In [47]:
# Power = watts = joules per second
power = pixels_hit * saturation_count * photon_J / exposure_time
print "ideal LO beam power = %.2f microwatts" % (power * 1e6)
What attenuation do we then use to get to ~single-photon levels?
In [50]:
atten = photon_J/(exposure_time * power)
print "attenuation to single-photon exposure = ", atten
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