Abstract

Ti:Al₂O₃ is presently the best laser medium for short pulse generation in the near infrared. This is clearly evident when the tunability and the average power output of Ti:Al₂O₃ lasers ^1-3 is compared to conventional femtosecond dye lasers. The introduction of Ti:Al₂O₃ boosted the average output power and the tunability of femtosecond oscillators by two orders of magnitude. In addition to generating short pulses, Ti:Al₂O₃ has also been shown to be an outstanding amplifier for producing ultra-high peak power pulses ^2,4,5 Although energies up to 1 J have been produced, the maximum repetition rate of these amplifiers is typically on the order of 10 Hz. This low repetition rate prevents the use of powerful spectroscopy techniques such as heterodyne or phase sensitive detection. On the other hand, Copper Vapor Laser (CVL) pumped dye amplifiers produce up to 10 μJ per pulse at repetition rates around 6 kHz. This energy is sufficient to create a spectral continuum. The spectral continuum itself is weak however, and needs to be reamplified to be used in typical pump and probe experiments ⁸. In a previous experiment we demonstrated the feasibility of picosecond pulses amplification at 1 kHz repetition rate in Ti:Al₂O3 ⁹. We present here a Ti:Al₂O₃ based regenerative amplifier pumped by a Q- switched Nd:YLF laser which is used to amplify femtosecond pulses at repetition rates up to 7.2 kHz.

© 1992 Optical Society of America