9311975 Fetterman A study will be conducted to test at microwave and millimeter wave frequencies several optomechanical media for use in four wave mixing experiments. These media are three-dimensional arrays of spatially fixed, electrically anisotropic particles that are small compared to the radiation wavelength. The particles are mechanically supported by torsional spring on the rigid supporting frame mounted with two microhinges and can undergo rotation due to electrostrictive torques exerted by incident radiation. Electrostrictive torques rotate the particles in such a way as to form orientational index gratings which can control the attributes of microwave or millimeter wave radiation. The susceptibility parameters of the optomechanical media will be obtained from two- wave mixing experiments using low frequency high-power pump beams and high frequency low-power probes. Four-wave mixing experiment will be performed to achieve phase conjugation and to evaluate the theoretical predictions of high nonlinear properties of optomechanical arrays. The thrust of this effort will be to demonstrate the feasibility of using orientational properties of mechanical structures as active elements to achieve phase conjugation in free space at both microwave and millimeter wave frequencies. Combining the concepts of micromachining and millimeter wave devices offers the possibility of entirely new classes of devices and systems. These will have a broad range of possible applications in future communication, power transmission and novel tracking systems. X ? Z b ! F 9 9 ( Times New Roman Symbol & Arial " h 7 %7 % O 1 Cassandra Queen Cassandra Queen