Quantum Noise in Optical Phase Conjugation Performed in an Atomic Vapor
Many researchers have studied the noise properties of optical amplifiers and have shown that all nonlinear optical amplifiers introduce noise into the amplified beam.1 In our research, we have conducted a theoretical and experimental investigation of the quantum noise generated by a phase-conjugate mirror (PCM) obtained using four-wave mixing in potassium vapor. An ideal PCM will generate light that exhibits excess quantum noise that is inherent to the phase conjugation process.2 Additional noise can be introduced as a result of fluctuations (e.g., collisions) in the nonlinear medium, as has been predicted for the nonlinear process of two-beam coupling in an atomic vapor.3 These sources of noise determine the fundamental limit on the smallest signal that can be phase-conjugated.
KeywordsQuantum Noise Noise Spectrum Noise Factor Phase Conjugation Atomic Vapor
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