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Intense ultrashort pulses are generated in an additive-pulse mode-locked, amplitude-feedback-controlled Nd:YLF laser pumped by quasi-cw laser diodes with a 30-Hz repetition rate. Pulse trains are produced that consist of approximately 600 single pulses of 2.1-ps duration and less, similar1-microJ energy. The peak intensity is less, similar0.5 MW, and a stability corresponding to a standard deviation of ~1.3% is measured. The optical efficiency of this all-solid-state mode-locked laser is determined to be ~1%.

An infrared dye laser is synchronously pumped by a cw mode-locked Nd:YAG system at 1.06 microm. The tuning range extends from 1.20 to 1.32 microm. A pulse duration of 3 psec was measured at 1.25 microm. The high photostability of the laser dye makes the laser system a practical device.

Substantial pulse deformation of picosecond pulses at lambda = 4.3 microm in air is observed, resulting from strong coherent interaction with 10 nearly equidistant rovibrational lines of the asymmetric nu(3) stretching mode of CO(2). The coherent reemissions of the different states interfere constructively after times of Deltat = 19 and 38 psec as expected from the frequency separation of two neighboring states of Deltanu = 1.75 cm(-1) according to the equation Deltat = (c x Deltanu )(-1).