Abstract

We have demonstrated a new way to generate subpicosecond pulses with high pulse energy at a high repetition rate. By enhancing the intracavity self-phase modulation in a Nd:phosphate glass regenerative amplifier, we can both amplify the picosecond pulse and broaden the pulse spectrum. The spectrally broadened pulses are then compressed by a pair of gratings to subpicosecond widths. A single Ar-ion laser was used to pump both a neodymium phosphate glass oscillator and a regenerative amplifier.¹ The oscillator was actively mode-locked by an acoustooptic modulator to generate 10-ps pulses at 100 MHz with an average power of 50 mW. A seed pulse (~5 pJ) from the oscillator was coupled into the regenerative amplifier which amplified the pulse energy to 16 µJ. Self-phase modulation in the Nd:glass broadened the pulse spectrum to ~15 Å. The pulse was compressed to 1.25 ps by a pair of gratings. To enhance the intracavity self-phase modulation, an unpumped slab of Nd:phosphate glass was inserted into the regenerative amplifier. The pulse spectrum was further broadened to ~33 Å. The pulse was then compressed to 0.55 ps with a pulse energy of 9 µJ and pulse repetition rate of 370 Hz.

© 1988 Optical Society of America