Publications by authors named "V S Sudarshanam"

We report ultraslow group velocities of light in an optically dense crystal of Pr doped Y2SiO5. Light speeds as slow as 45 m/s were observed, corresponding to a group delay of 66 micros. Deceleration and "stopping" or trapping of the light pulse was also observed.

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Optical aberrations that are due to high-speed turbulence in the aero-optical regime are corrected with optical phase conjugation based on coherent population trapping in sodium vapor. Experimental measurements of an unheated, forced helium jet in air have demonstrated aberration correction by a factor of 7.8 at a forcing frequency of 18kHz with an optical power gain of 32.

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We observed optical gain as great as 30 with nearly distortion-free beam propagation in optically dense sodium vapor, using four-wave mixing. Moreover, 15-dB classical noise correlations were seen in the amplified probe and conjugate beams. To achieve this performance in such a strongly absorbing medium, one must suppress unwanted absorption and self-focusing effects.

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A highly efficient optical polarization and phase modulator formed by the placement of a thin transparent piezofilm with indium tin oxide electrodes directly in the path of the output from an optical fiber is presented. Various configurations that differ in the clamping conditions, utilization of epoxy, and optical arrangement are presented. For a film thickness of 63.

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A new configuration of the fiber-optic extrinsic Fabry-Perot interferometer is demonstrated. This configuration utilizes two sensor heads on a single directional coupler in a split-cavity cross-coupled extrinsic fiber interferometric (SCEFI) arrangement to provide a four-beam interference. The need for quadrature phase biasing is eliminated, with a new spectrum analysis detection scheme devised for the SCEFI in a no-feedback condition.

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