Dispersion of the Two-Photon Absorption Coefficient in a Silica Optical Fiber

Abstract

Recently investigations of the nonlinear optical properties of silica fibers in the ultraviolet region have been promoted by the development of medical applications of ultraviolet lasers such as excimer lasers. In the wavelengths less than ~310 nm, twice the photon energy corresponds to the band edge of fused silica. Therefore two-photon absorption occurs as well as in germanosilicate or lead-glass fibers in the blue-green region. The two-photon absorption of ultraviolet radiation induces intensity-dependent loss, which is serious for short-pulse lasers. Further, defects are more or less generated by two-photon absorption, which degrade the fibers. So that, it is important to clarify the characteristics of two-photon absorption, especially the dispersion.