Abstract

We report the generation of tunable femtosecond pulses in the 690-750 nm wavelength region, by selective continuum amplification and subsequent recompression, in a CPM based ultrashort pulse system. The continuum is generated in a jet of ethylene glycol with amplified CPM pulses at 620 nm. The amplified continuum pulses are typically of duration 75-85 femtoseconds (assuming a sech² profile) with energies per pulse of several microjoules, at a repetition rate of 8.5 kHz. The pump source for the amplifier is a copper vapor laser. The dyes used as the gain medium for the continuum amplifier are LDS 698 and LDS 750, which, even though they are significantly less efficient than Rhodamine or Styryl 9, accomplish the desired purpose. These pulses are then launched in a 10 mm length of single mode fiber to produce a broad spectral continuum which is then compressed to pulses of duration 12-13 femtoseconds. Ultrashort pulses in this wavelength range will be useful for resonant investigations of quantum well structures.

© 1990 Optical Society of America