Generation of narrow linewidth pulses via amplification in a chain of fiber/bulk amplifiers

Summary form only given.Laser sources with energies in the microjoule to millijoule range are used in a multitude of applications. Many applications require narrow linewidth and tunability. The traditional approach employed is to use a low power, narrow linewidth master laser to injection seed a high power slave oscillator. In order for the oscillator to operate at the seeder frequency the cavity of the former has to be resonant with the seeder mode. Two alternative approaches are currently employed to achieve this goal: (1) the minimization of the build-up time or (2) the ramp-fire technique, in which the Q-switch is fired, when a resonance is detected while one cavity mirror is ramped rapidly. An alternative approach is presented. The beam of a low power seed source is gated with an electro-optic gate and then consecutively amplified first by a high gain fiber amplifier (up to 60 dB gain) followed by four-passing through a bulk amplifier. In contrast to a Q-switched fiber laser, our configuration does not form a closed cavity and no resonance condition must be fulfilled.