Abstract

We have developed a Nd:YLF regenerative-amplifier-based (RA-based) system for synchronous amplification¹ of femtosecond pulses from a passively mode-locked dye laser (CPM) at rates approaching 20 kHz. The higher repetition rates, which are desirable for improved signal-to-noise ratios in scientific experiments, are limited only by the pumping rate of the RA. The two significant features of the system are (1) the operation of the RA at greater than 10 kHz and (2) the synchronization of the output of the RA to the colliding-pulse mode-locked (CPM) laser. This is achieved by FM mode-locking a diode-pumped Nd:YLF seed laser with an RF signal that is phase-locked to the output of the CPM. The use of an FM mode-locking scheme relaxes the requirement that the CPM and seed laser cavities be exactly matched. The picosecond pulses from the seed laser are amplified to the millijoule level in the RA, frequency doubled, and then used to synchronously pump a dye amplifier. Synchronous amplification with short pump pulses (d ps) permits more efficient amplification and creates the potential for higher pulse energies than are currently available with copper-vapor laser-based asynchronous amplifiers.²

© 1990 Optical Society of America