Effect of signal frequency on four-wave mixing through stimulated Brillouin scattering.

We present measurements of the dependence of the phase-conjugate reflectivity on signal frequency for Brillouinenhanced four-wave mixing at pump intensities above the threshold instability. The measurements were made in TiC1(4) at lambda = 1 microm and are consistent with a computer model of the reflectivity. We have observed that the frequency of the conjugate beam is independent of the frequency of the input signal beam in the unstable regime.

Phase locking two beams by means of seeded Brillouin scattering.

We have demonstrated that the phases of the stimulated Brillouin scattering reflections of two separately focused pump beams can be locked to a common phase by a backward seed of pump laser light.

Observation of amplified reflection through degenerate fourwave mixing at CO(2) laser wavelengths in germanium.

We report the first known observation of amplified reflection through degenerate four-wave mixing at 10.6 microm. Reflectivities of over 100% are reported in both n-type and p-type germanium at pump intensities of about 100 MW/cm(2). The maximum reflectivity reported is 800% in p-type Ge.

Observation of resonantly enhanced degenerate four-wave mixing in doped alkali halides.

We describe the first reported observation of resonantly enhanced phase conjugation through degenerate four-wave mixing (DFWM) in doped alkali halides. We also describe the first reported quantitative comparison of the resonant DFWM process in the infrared with the theory of Abrams and Lind [Opt. Lett. 2, 94 (1978); 3, 205 (1978)]. The comparison for small values of alpha0L is shown to be excellent. For alpha0L in excess of 3, experiment and theory diverge because of pump attenuation by the resonant medium.

Determination of the third-order nonlinear optical coefficients of germanium through ellipse rotation.

We describe the first reported direct determination of the 10 -Am nonlinear susceptibility in intrinsic Ge through time-resolved ellipse rotation. We found that X(3)(1111). = 2.5 X 10(-11) esu and X(3)(1221)= 1.3 X 10(-11) esu, significantly below previous estimates.