Nonlinear Response of a Suspension Medium to Millimeter-Wavelength Radiation

Abstract

A nonperturbative method for describing the response of an orientational Kerr medium to arbitrarily strong electromagnetic fields is presented. The method is used to analyze recent phase-shift measurements for the static birefringence and new measurements for the time response of a suspension medium as functions of millimeter-wave intensity. Excellent agreement between theory and experiment provides the effective parameters in terms of which the nonlinear optical properties of the medium are assessed for applications to the millimeter-wave regime.

Polarization-resolved beam combination in liquid suspensions of shaped microparticles

“…(2.6) j=1 Here 1 (2) refers to the pump (probe): A, e, co, and K are the amplitude, unit polarization vector, frequency, and the propagation vector of the jth beam. The interaction potential U(r, 0, $;t) has both static terms as well as terms that oscillate at the difference frequency.…”

“…In both the configurations, the changes in the intensity of the transmitted probe beam produced by energy transfer are detected by a large area photodiode (D) and (2) write beams linear, orthogonal polarized; (3) pump beam linear, probe wave circular polarized; (4) write beams circularly polarized in the same direction (corotating beams); and (5) write beams circularly polarized in the opposite direction (counterrotating beams). We also present theoretical calculations that span the regime from the corotating to counterrotating cases.…”

“…For energy transferred into the original polarization direction (denoted by Q, ", ") we have Q, "=-,'((K, +K")), the mirror velocity and the orientational gratings evolves from one steady state to another. (2) The laser beams are initially off, the mirror moving at a constant velocity, and the beams are then switched on at t =0. The response of the gain at a single fixed frequency for different times after t =0 is measured.…”

“…Finally, beam combination was also achieved using degenerate laser beams and moving the suspension relative to the laser interference pattern. four-wave mixing [4 -6] (DFWM) have been performed in two difFerent classes of shaped microparticle media: (1) a nonaqueous suspension of carbon fibers and (2) waterglycerol suspensions of shaped polytetraAourorethylene (PTFE) particles. The optical anisotropy of these two suspensions arises from different causes.…”

“…The optical birefringence and phase conjugation studies noted above probed the transient dynamics and the nonlinear-optical characteristics of shaped particle suspensions arising from static electromagnetically induced index gratings. Experiments with the carbon fiber suspensions were performed at microwave and millimeter wavelengths [2,4], while those with PTFE suspensions [1,5,6] were carried out at visible wavelengths. 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.…”