Stable pulsed picosecond GSGG:Nd3+ laser with a resonator based on Sagnac interferometer

An investigation was made of the characteristics of a laser with a new active medium in the form of neodymium-activated gadolinium scandium gallium garnet (GSGG:Nd³⁺), containing chromium and emitting ultrashort pulses in the case of passive mode locking. Statistical dependences of the duration, energy, and reproducibility of the output pulses on the position of a cell with a saturable absorber (dye 3274 in ethanol) in an interferometer and on the initial transmission of the cell were determined. A new resonator configuration with an asymmetric position of the active element inside an interferometer ring was used: it ensured simple emission of the lowest transverse mode without additional spatial selection. A comparison of the main parameters of the ultrashort pulses emitted by YAG and GSGG lasers demonstrated characteristic advantages of the new active medium in generation of picosecond pulses.