[OPTICAL REVIEW Vol. 5, No. 1 (1998) 49-53]

Study on Optimum Incident Angles of Cross Polarized Four-Wave Mixing with a Photorefractive Crystal

Yoshihisa TAKAYAMA1 Atsushi OKAMOTO1 Kunihiro SATO2 Kazuhumi KUMAGAI1 and Yugo AIZAWA1

1Optical Processing & Network Laboratory, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido, 060 Japan, 2Faculty of Engineering, Hokkai-Gakuen University, Sapporo, Hokkaido, 064 Japan

(Received September 29, 1997; Accepted December 9, 1997)

We consider the optimum incident angles of cross polarized four-wave mixing with a photorefractive crystal. First, the phase matching angles are obtained for two operation modes: one in which the writing beams are ordinary rays and the reading beam is an extraordinary ray, we call this Mode 1. The other in which the writing beams are extraordinary rays and the reading beam is an ordinary ray, Mode 2. Next, practicable ranges of the incident angles are calculated considering of the total internal reflection of the phase conjugate beam in cases where the two writing beams illuminate the same surface of the BaTiO3 crystal and where they illuminate the neighboring right-angled surfaces, respectively. Then, the coupling coefficient is determined as a function of the incident angle, and the optimum incident angles for effective beam interaction in Mode 1 and Mode 2 are estimated.

Key words : photorefractive, cross polarized four-wave mixing, phase conjugation, phase matching angle, coupling coefficient