Unprecedented Raman cascading and four-wave mixing from second-harmonic generation in optical fiber.

We experimentally demonstrate strong second-harmonic-generation from a self-induced all-optical poling in germanium-doped fiber with a subnanosecond laser pump at 1064 nm. The large second-harmonic conversion efficiency allows nonlinear spectral broadening at visible wavelengths so that up to nine distinct Raman sidebands have been obtained. In this work we emphasize how the Raman scattering, induced from the pump in the IR region, can drastically affect the optical poling effect, limiting in turn second-harmonic generation.

Optical poling in germanium-doped microstructured optical fiber for visible supercontinuum generation.

We report visible supercontinuum generation initiated by the second harmonic generation obtained in a germanium-doped microstructured optical fiber after optical poling processing. The visible spectral broadening is due to a cross-phase modulation effect between the generated IR solitons and the second harmonic (532 nm) of the 1064 nm pump wave. The 400-650 nm white-light emission is obtained on the fundamental propagation mode of the fiber.

Picosecond polarized supercontinuum generation controlled by intermodal four-wave mixing for fluorescence lifetime imaging microscopy.

We present the generation of a picosecond polarized supercontinuum in highly birefringent multimodal microstructured fiber. The initial steps of the spectral broadening are dominated by intermodal four-wave mixing controlled by the specific fiber design. Using a low repetition rate ultra-stable solid state laser, a pulse train well-suited for versatile time-domain fluorescence lifetime imaging applications is obtained.

Ultra wide band supercontinuum generation in air-silica holey fibers by SHG-induced modulation instabilities.

Second harmonic generation in an air-silica microstructured optical fiber pumped by subnanosecond pulses is used in order to initiate modulation instability processes in normal and anomalous dispersion regimes. This allows us to generate an ultra wide and flat supercontinuum (350-1750 nm), covering the entire transparency window of silica and exhibiting a singlemode transverse profile in visible range.