Generation of nanosecond and subnanosecond laser pulses by AlGaAs/GaAs laser-thyristor with narrow mesa stripe contact

Lasers-thyristors with a narrow (20 μm) mesa stripe contact have been studied. It was shown that the laser peak power reaches a value of 2.5 W in the long-pulse mode at a pulse width of 13 ns. It was demonstrated that generation of a controlled train of laser pulses with peak power of 1.6 W and width of 90 ps is possible in the short-pulse mode. The maximum value of the pulse repetition frequency was 470 kHz at the following working characteristics of the laser-thyristor: blocking voltage 5.8 V, control current pulse 25 mA. A number of specific features were observed in the short-pulse mode. It was found that the blocking voltage and amplitude of the control current pulse affect the lasing process. We observed that in short pulse mode the lasing spectra have a two-band structure and the lateral near field may degenerate into a single spot with size substantially smaller than the mesa stripe width. It was shown that the main reason for the observed specific features of lasing is the clearly pronounced effect of the spatial localization of the current.