Abstract

Picosecond self-pumped phase conjugation and two-wave coupling in the near-infrared region in SBN:Ce crystal were studied. The schematic diagram of the experimental setup for phase conjugation of picosecond pulses is shown in Fig. 1. A cw mode-locked. Ti:sapphire laser was used as the pump source. The repetition rate of the mode- locked Ti:sapphire laser was 82 MHz, and the pulse width was 1.5 ps (FWHM). The spectral width of the laser pulse was measured to be 0.48 nm, centered at 778 nm. This yields t_pΔv_p = 0.36, close to the Fourier-transform limit of sech² pulses. An optical isolator was used to isolate the feedback between the phase conjugator and the mode-locked laser. A single-domain SBN:Ce crystal with dimension of 5 × 5 × 5 mm³ was immersed in a cuvette filled with index-matched oil (n = 1.5) to reduce the reflection losses at the crystal surfaces. The index grating vector k_g was chosen to be parallel to the c axis of the crystal. The phase-conjugation reflectivity R_pc was measured to be 58% with an error of ± 3% at 778 nm for an average pump power of 92 mW.

© 1994 Optical Society of America