Generation of single ultrashort light pulses with the aid of a "combustible" mirror

The power density in the resonator of a self-mode-locked neodymium laser was limited by a mirror with a metal coating which was burnt through during the initial stage of the laser action. This limitation made it possible to increase considerably the initial density of the nonlinear absorber used in the resonator. In this way stable and sufficiently full mode locking was achieved. A considerable variation in the amplitudes of the ultrashort pulses at the beginning of a train was due to the use of a dense nonlinear absorber. This circumstance, in combination with the stoppage of the laser action on destruction of the mirror coating, enabled us to select reliably a single ultrashort pulse with a contrast of the order of 10.