Abstract

Ultrafast high peak power near infrared laser systems are important in nonlinear biomedical imaging applications including two-photon excitation fluorescence (TPEF) or second harmonic generation (SHG) microscopy that are currently dominated by pulsed solid state lasers. The detected intensity in TPEF and SHG depends quadratically on the pulse peak power and linearly on the pulse width and repetition rate. Quantum-dot (QD) based semiconductor pulse sources have shown to generate ultrashort pulses and high peak power [1]. QD semiconductor optical amplifiers (SOA) are very suitable to increase the power of these ultrashort pulses due to their high gain saturation characteristics, broad gain bandwidth and fast gain recovery. Such combined systems are compact, efficient and robust thus being promising alternatives to solid state pulsed lasers. Recently, an external cavity laser and amplifier combination was reported exhibiting a pulse peak power of 30W and an average power of 208mW at a repetition rate of 648 MHz and a pulse width of 10.6 ps. This configuration has been successfully applied in TPEF [2].

© 2013 IEEE