Abstract

Current modulation of the pump diode laser in a lithium neodymium tetraphosphate (LNP) close-coupled cube (C² cube) laser¹ provides a convenient way to generate a regular train of submicrosecond long pulses without changing the device geometry. Spike-mode oscillation in external mirror LNP lasers at a maximum repetition rate of 200 kHz has been previously described by Kubodera and Otsuka.² We report the observation of single frequency, spike-mode oscillation at frequencies near 1 MHz from C² cube lasers. For substantial modulation amplitudes (>20%) at an average cw pump power approximately two times the lasing threshold, we have observed stable spiking over a frequency range of 590-940 kHz. A peak power enhancement (peak spike power divided by cw power at the same average input power level) of > 10 was obtained at 590 kHz. Resonant relaxation oscillation with reduced amplitude has also been observed at 2.2 MHz.

© 1989 Optical Society of America