Controlled light Localization and Nonlinear-Optical Interactions of Ultrashort Laser Pulses in Micro-and Nanostructured Fibers with a Tunable Photonic Band Gap

摘要

Physical principles behind the control of light localization and nonlinear-optical interactions in micro- and nanostructured fibers are demonstrated. Transmission measurements on the cladding of nanostructured fibers having a form of a two-dimensional periodic structure with a pitch less than 500 nm have revealed the existence of a photonic band gap tunable within the range from 930 to 1030 nm. The influence of the structure of the holey-fiber cladding on the effective area of the waveguide mode and the spectral broadening of Ti:sapphire and Cr:forsterite femtosecond laser pulses is experimentally studied. It is shown that the increase in the air-filling fraction of a holey-fiber cladding results in a considerable enhancement of spectral broadening of short laser pulses due to the increase in the light localization degree in the fiber core.