Picosecond parametric oscillator amplifying radiation from a tunable semiconductor laser

A picosecond optical parametric oscillator based on an LiNbO3 crystal was built, amplifying narrow-band radiation from a tunable semiconductor laser emitting at near 4 micron. The oscillator was pumped by single spectrally limited picosecond pulses of 6-7 nanosec duration from a neodymium glass laser. The semiconductor laser was made of PbS, emitting pulses at liquid nitrogen temperature when pumped by a current of 15A. Synchronizations of the semiconductor and picosecond (neodymium) lasers were achieved by a photodiode receiving radiation energy from the picosecond optical parametric oscillator. The ratio of the energy of the amplified signal to the energy of the superradiance traveling within the same solid angle (for the same signal/noise ratio) was determined. The instrument is used in picosecond spectroscopy.