TUNABLE ULTRAVIOLET FEMTOSECOND PULSES AT KILOHERTZ REPETITION RATES

Femtosecond pulses, tunable between 250 and 400 nm, are generated at a pulse repetition rate of 8 kHz by two methods, sum-frequency generation and second-harmonic generation. Both methods produce pulse energies ranging from approximately 10 pJ at 280 and 380 nm to 40 nJ at 310 nm. Between 250 and 280 nm, sum-frequency generation produces pulses with energies significantly greater than those produced by second-harmonic generation. The measured pulse duration at 310 nm is 180 fs.