Control of the laser spectrum and duration of emission by sampling of the reflection coefficient of a parametric nonlinear mirror with an external ultrashort pulse train

Control of the reflection coefficient of a ‘nonlinear’ mirror by an external train of ultrashort pulses from a YAG:Nd laser was investigated. This mirror was part of a synchronously pumped dye laser and it was based on generation of the sum and difference frequencies. The mirror reduced the spectral width of the emission line of the dye laser to 0.2 nm and made tuning possible over the whole gain band. The kinetics of formation of spectral and time parameters of lasing was studied. Time sampling of the reflection coefficient of the mirror by external radiation reduced by a factor of 3 – 4 the duration of ultrashort pulses emitted by the dye laser.