Simultaneous narrow linewidth and broadband operation in the master oscillator power amplifier of a self-seeded Ti:sapphire laser

A narrow linewidth pulse and a broadband pulse were simultaneously operated in the master oscillator power amplifier (MOPA) of a self-seeded Ti:sapphire laser, and their intensity ratio was varied by increasing the incident pump energy. The broadband pulse from the independent free-running oscillation was preferentially amplified in the MOPA chain and replaced the narrow linewidth pulse. This explanation was confirmed by comparing the behavior with that of a bandpass filter inserted at the exit of the oscillator. The behaviors were well simulated by numerical calculations. From the results, a method to produce both narrow linewidth and broadband pulses was proposed with their ratio depending on the pump energy.

► Narrow linewidth and broadband pulses were simultaneously operated.
► Intensity ratio of narrow and broadband pulses depended on the pump conditions.
► A method to produce pulses with different spectral properties.