Mixing partially coherent fields with gaussian irradiance profiles; optimization criteria.
A detailed analysis of the average signal-to-noise ratio (SNR) resulting from the mixing or heterodyning of partially coherent, collinear beams with gaussian irradiance profiles is undertaken. It is shown that SNR can be expressed as a function of the beam cross sections and coherence areas and the area of the photodetector. The dependence of SNR on each of these parameters is examined. The previously observed saturation phenomenon, as well as coherence suppression and degradation effects, are observed and explained theoretically. Optimum values of the local oscillator beam size and coherence area are derived which generally produce the best SNR for a given set of signal beam parameters.
Lahti
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JN
Nagel
C M
CM