Femtosecond fiber laser pulses amplified by a KCl:Tl^+ color-center amplifier for continuum generation in the 15-μm region

Abstract
A diode-pumped stretched-pulse additive-pulse mode-locked Er-doped fiber laser is used to seed a KCl:Tl + color-center amplif ier crystal. The initial l-nJ chirped pulses are double passed through the amplif ier, which is pumped by a 1-kHz Q-switched Nd:YAG laser. The resulting 10-microJ pulses are then chirp compensated to 250-fs duration and are used to generate a spectral continuum. A few high-n(2) materials are investigated for continuum generation, and spectral slicing of the continuum is demonstrated.