Barium titanate is most widely used as a photorefractive material because of its large photorefractive gain. Large gains are used for generating optical phase conjugate beams and for some signal processing applications.1 Recently, photorefractive effects at wavelengths compatible with laser diodes have become important.2 They have been used for laser mode narrowing and locking laser diodes to the same wavelength.3 Unfortunately, the photorefractive gain in barium titanate is substantially lower at near IR wavelengths than in the visible. Theory predicts that the photorefractive gain will decrease linearly with increasing wavelength. Here we experimentally determine the wavelength dependence of the photorefractive gain in a barium titanate crystal. By linearizing the gain data we obtain information about how the effective trap density varies with wavelength.
© 1990 Optical Society of AmericaPDF Article