Two-color Semiconductor Mode-locked Laser system for Multiphoton Imaging Applications

We demonstrate an all-semiconductor mode-locked laser system consisting of two external cavity mode-locked lasers operating at wavelengths 834 nm and 974 nm which use semiconductor optical amplifiers as gain media. The two-color laser system emits picosecond pulses with average powers of 25 mW and 60 mW resulting in peak powers exceeding 100 W and 80 W respectively. Synchronized output pulse trains from the lasers with a repetition rate of 282 MHz exhibit a relative timing jitter of 7.3 ps. Fiber coupled output from the laser system delivers an ideal output beam with TEM₀₀ mode profile. Peak power densities >1 GW/cm² can be achieved by focusing the output beam to a smaller spot with 4 μm diameter, which is crucial for applications that requires excitation of optical nonlinearities.