Optimization of the incident condition for a CAT self-pumped phase conjugator by erasure

Gilmore J. Dunning, David M. Pepper, Marvin B. Klein +1 more

Satoshi Honma, Takashi Amano, Syunsuke Uemura +3 more

Atsushi Nakamura, Tsutomu Shimura, Kazuo Kuroda

Masayoshi Dohata, Atsushi Okamoto, Koji Enbutsu +1 more

Abstract The properties of the phase‐conjugate reflectivity are analyzed anew for the self‐pumped four‐wave mixing in which only the two waves, i.e., the forward pump wave and the probe wave, are incident on the photo‐refractive crystal and the phase‐conjugate wave of the forward pump wave is used as the backward pump wave. First, by means of a model in which a Cat‐type phase conjugator is placed outside the interaction region, the equation for the phase‐conjugate reflectivity of self‐pumped four‐wave mixing using a transmission grating is derived. Next, the numerical calculations have been used for the first time to determine the effects of the coupling strength, the probe ratio as the incident intensity ratio of the forward pump wave to the probe wave, and the reflectivity of the Cat‐type phase conjugator on the entire phase conjugate reflectivity. Since the equation describing the phase‐conjugate reflectivity has multiple solutions, the strict analysis of the equation shows that the phase‐conjugate reflectivity has multiple values. Further, the conditions for high phase‐conjugate reflectivity has been studied.

Kenneth R. MacDonald, Jack Feinberg

D. A. Noraev, Patrick Lambelet, Jack Feinberg

We measure the spectral reflectivity of a Cat (so named because its first conjugated image was that of a cat) self-pumped conjugator. We find that the transmission and the phase-conjugate reflectivity of the conjugator always vary periodically with wavelength and that the periodicity is caused by a resonator loop that springs up and self-adjusts inside the crystal. Depending on the spectral width of the incident beam, the conjugator will have either a minimum or a maximum reflectivity at the center of the writing spectrum. We show that the sign of the coherence function after one round trip of the internal resonator determines the spectral behavior of the conjugator, and we experimentally map out the dependence of the conjugator’s reflectivity and transmission on the spectral content of the incident beam.