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 theQof 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.