Two-wave coupling and self-pumped phase conjugation at near infrared wavelengths in BaTiO 3

Abstract

Using an undoped BaTiO 3 crystal, the reflectivities of the self-pumped phase-conjugate mirror operated in total internal-reflection geometry (TIR) at near infrared wavelengths from 706 to 850 nm were measured. The phase conjugation reflectivities R pc > 50% at 706 to 760 nm, R pc=40% at 816 nm, and R pc=20% at 850 nm were observed. The two-wave coupling exponential gain coefficient Γ and the photorefractive index grating formation rate τ -1 PR as a function of wavelength from 706 to 850 nm were studied. The exponential gain coefficients Γ=11.1 cm -1 at 706 nm and Γ=7.6 cm -1 at 850 nm were obtained. It was also found that the absorption coefficient α in the near infrared wavelengths is much smaller than that in the visible region.