Threshold sensitivity of a projection optical system based on a brightness amplifier with a four-wave hypersonic phase-conjugating mirror under absolute instability conditions

The threshold (maximum) sensitivity was achieved experimentally for a projection system comprising a highly sensitive four-wave hypersonic phase-conjugating mirror and optical quantum amplifiers. The sensitivity at λ = 1.054 μm amounted to 4.8 X 10 ^– 19 J (2.4 photons) per resolution element. The results obtained were confirmed by theoretical estimates.