It has been shown recently (see, e.g., Nature, <b>397</b>, 594, 1999; <b>409</b>, 490, 2001) that light pulses can be remarkably slowed down in resonant gases under very low temperatures. We show theoretically and experimentally that a similar in nature (and stronger in value) phenomenon occurs in photorefractive nonlinear media. The pulse-maximum velocity can be reduced here to the value of <i>thickness/response time</i> because of the two wave coupling effect. Specific properties of pulse propagation depend on the type of the photorefractive response and also duration and shape of the input pulse. Our theoretical results for the nonlocal nonlinear response are in a good agreement with experimental data obtained with BaTiO<sub>3</sub> and Sn<sub>2</sub>P<sub>2</sub>S<sub>6</sub> crystals.
© 2003 Optical Society of America