Birefringence-controlled anti-Stokes line emission from a microstructure fiber

Microstructure fibers with a specially designed form birefringence are shown to be shown to be ideally suited for the creation of highly efficient frequency-tunable sources of short pulses in the visible range. We use unamplified 35-fs pulses of 820-nm. Ti: sapphire laser radiation to demonstrate efficient generation of an intense anti-stokes signal in an elliptical-core fused silica microstructure fiber. The central wavelength of this anti-Stokes signal can be switched between 490 and 510 nm by coupling the pump pulses into the fast and slow modes of the microstructure fiber.