EXTENSION OF THE TUNING RANGE OF A FEMTOSECOND TI-SAPPHIRE LASER-AMPLIFIER THROUGH CASCADED 2ND-ORDER NONLINEAR FREQUENCY-CONVERSION PROCESSES

The article presents single step and cascade methods for converting the femtosecond radiation from a 1 kHz repetition rate Ti:sapphire regenerative amplifier to the near-infrared (1.2-1.5 μm and 1.6-2.2 μm), visible (554-593 nm), and for the first time to our knowledge to the vacuum ultraviolet spectral region well below 190 nm. Using only solid state materials (nonlinear optical crystals) femtosecond pulses are generated through phase-matched mixing processes down to 172.7 nm. The developed scheme for femtosecond parametric conversion provides nearly bandwidth limited femtosecond pulses, whose duration is comparable or even shorter than that of the pump pulses. The temporal gain narrowing in the optical parametric amplifier is identified as a pulse compression mechanism on the femtosecond time scale leading to generation of infrared light pulses as short as ≊50 fs. As a whole our all-solid state laser complex provides independently tunable and synchronized sub-200 fs light pulses simultaneously at several wavelengths and practically without relative jitter. © 1994 American Institute of Physics.