Polarization-resolved nondegenerate two-wave mixing in shaped microparticle suspensions

Abstract

We observe polarization-resolved coherent beam combination through nondegenerate two-wave mixing in water-glycerol suspensions of shaped polytetrafluoroethylene microparticles. Coherent energy transfer that arises from translational and orientational moving index gratings was observed. A theory for beam combination through nondegenerate two-wave mixing is presented and found to be in excellent agreement with these measurements.

Measurements of light-scattering noise accompanying two-wave mixing in a Kerr medium

“…2(b). Note that both the experimental and theoretical gain profiles follow frequency dispersion curves characteristic of the Debye relaxation model [8,10]. More importantly, there is excellent agreement between theory and experiment in regard to the rms values of the noise fluctuations, including their dependence on frequency shift.…”

“…The factor (kTv) is the Nyquist expression for the thermal noise power radiated by a channel having a bandwidth equal to the optical frequency v. Equation (8) yields a predicted average noise power at zero probe power of 0.2 pW due entirely to scattered pump light. The stochastic noise model sampling confirms this result and gives an rms power of 0.28 p%'.…”

“…In the present experiments we typically used a 1% volume fraction of PTFE particles suspended in a 65-35 water-glycerol host-liquid mixture. This mixture was chosen because it matches the average value of the particle refractive index no = 1.376, thus minimizing the importance of lightscattering fluctuations due to the isotropic part of the particle polarizability (8). Figure 1 shows the experimental setup for nondegenerate two-wave mixing.…”

“…The single data point on the ordinate gives the rms noise power measured in the absence of the probe beam as discussed in connection with Eq. (8).…”

Polarization-resolved beam combination in liquid suspensions of shaped microparticles

“…Good agreement was found between theory and experiment in both cases, especially with regard to medium response time, magnitude, polarization characteristics, and intensity dependence of the nonlinear susceptibilities of these suspensions. This research extends these studies to the physics of moving optical index gratings [7,8] in one class of shaped particle suspensions, namely, PTFE.In this paper experimental and theoretical studies of' beam combination via nondegenerate two-wave mixing (NDTWM) at argon-ion wavelengths in liquid suspensions of PTFE are reported. In NDTWM, energy transfer is achieved by creating optical index gratings that are out of phase with respect to the electromagnetic interference pattern that establishes them [9,10].…”