Nonlinear refractive index of photo-thermo-refractive glass

Nonlinear properties of a photo-thermo-reftactive (PTR) glass are studied and compared with those in fused silica and a conventional optical glass. PTR glass is a new photosensitive medium for high-efficiency phase volume hologram recording which manifests a linear refractive index modulation after exposure to UV radiation followed by thermal treatment. Nonlinear optical properties-of PTR glass exposed to feratosecond laser pulses are studied. Diffraction patterns in a propagated laser beam focused in the sample were detected by a CCD, while a nonlinear refractive index was measured by a collinear-orthogonal-polarization-pump-probe (COP3) method. It was found that nonlinear refractive index of PTRG is n(2) = 3.3 x 10(-20) m(2)/W (0.33 ppm cm(2)/GW) which is about the same as for the fused silica. It is important that n2 in PTR glass does not vary after UV exposure and thermal development. (c) 2005 Elsevier B.V. All rights reserved.