Two-dimensional Optical Beam Research Articles

Optical beams in saturable self-focusing media.

An approximate analytical analysis of two-dimensional optical beams propagating in saturable self-focusing media is carried out. In particular, the radial shape and the phase shift of the stationary self-trapped fundamental mode are investigated in detail. The dynamic variations of the beamwidth and the phase shift for nonstationary propagation are also analyzed. The predictions of the analytical model are compared with numerical results for stationary propagation and show good agreement. © 1992 The American Physical Society.

Optical Solitons in Media with Resonant and Non-resonant Self-focusing Nonlinearities

Special features of generating a self-induced transparency in a medium with both resonant and non-resonant (Kerr-type) nonlinearities are considered. Soliton solutions of the Maxwell-Bloch equations are found, taking into account the diffraction divergence of the light beam. It is shown that solitons emerge in such a medium under conditions of two-dimensional optical beam scanning along the medium surface, and have non-coinciding propagating directions of the amplitude and phase fronts. As a necessary condition for the existence of solitons, there is a definite relationship between the scanning velocity and the parameters of the medium and radiation.

Focusing Ultrasonic System Applicable to Two-Dimensional Optical Beam Scanning and Laser Output Modulation

Recent interest in (1) the directional control of highly collimated light beams and (2) internal modulation of laser action has stimulated a variety of experiments. This paper reports on experiments utilizing a barium titanate ceramic transducer formed into an arc of a short section of right circular cylinder and radiating into a tetrachloroethylene-filled cell at 400 kc/sec. A helium-neon laser beam was used to examine the index of refraction gradients produced in the liquid and to illustrate the possible deflection patterns. When the beam traversed the cell near the focal line, circular scanning was observed, with maximum deflection angles of approximately ±1.0°. Linear scanning reached ±1.3°. Data describing the experimentally observed beam motion showed good agreement with a theoretical analysis of the complex acoustic field in this region. Deflections produced by pulse excitation of the transducer exceeded ±1.5°. Ruby laser spiking was modulated to follow the 400-kc/sec field, and in pulsed operation giant spikes were obtained, using the cell to control the Q of the optical resonator cavity. High-speed photographs of both the partial standing acoustic wave, the traveling shock waves, and the circular beam-deflection pattern were taken.