Abstract

The phenomena of self-pulsation, oscillation chaos, and frequency shift in selfpumped photorefractive BaTiO₃ crystal have been recently studied.¹,² In this paper we present the pulsation and chaotic phenomena in self-pumped BaTiO₃ for both divergent and convergent beams focused at various locations near the crystal surfaces. An argon laser (Innva model 70) operating at 488 nm pumps a 6- × 3- × 6-mm BaTiO₃ crystal which was mounted on a translation stage to control the incident beam focusing location. The front c-face of the crystal was taken as the reference plane with the top right corner coordinate defined as (x, y) = (0,0). The convergent and divergent beams (within the crystal) are defined by focal points at (3, 6) and (3, –6) mm, respectively, where the c-axis is along the 6-mm length. A focal length f = 200 mm was used to keep the incident beam the same spot size of 1 mm on the crystal surfaces for both convergent and divergent cases.

© 1989 Optical Society of America