We present the results of a numerical model and proof-of-principle experiment for temporal phase control using phase-sensitive parametric amplification. Under certain conditions, temporal phase amplification can be achieved in this process.
In the presence of a nonzero idler beam or, equivalently, in the collinear degenerate configuration, optical parametric amplification (OPA) can be phase sensitive. When the photon deamplification mode is selected in the OPA process, amplification of the optical phase occurs instead of the usual amplification of photon number. We demonstrate for the first time, to the best of our knowledge, that the operation of a spatially multimodal optical parametric amplifier in the phase-sensitive mode can result in a significant redistribution of spatial frequencies and near-ideal beam angle amplification. A numerical model is presented for phase-sensitive parametric amplification via three-wave mixing. The model is applied to monochromatic beams and finite beam apertures. The sensitivity of gain to the incident phase, noncollinear angle, and aperture size is studied in particular. Simple conditions are derived for the operation of the optical parametric amplifier in the phase-sensitive mode. Potential applications of the concept are discussed.
A cascaded parametric amplifier consists of a first parametric amplifier, which amplifies an input signal and generates an idler, which is a copy of the signal, a signal processor, which controls the phases of the signal and idler, and a second parametric amplifier, which combines the signal and idler in a phase-sensitive manner. In this paper, cascaded parametric amplification is modeled and the conditions required to maximize the constructive-destructive extinction ratio are determined. The results show that a cascaded parametric amplifier can be operated as a filter: A desired signal-idler pair is amplified, whereas undesired signal-idler pairs are deamplified. For the desired signal and idler, the noise figures of the filtering process (input signal-to-noise ratio divided by the output ratios) are only slightly higher than those of the copying process: Signal-processing functionality can be achieved with only a minor degradation in signal quality.