Transient frequency shift in a single-mode quasi-continuous diode-pumped Nd:YAG laser

The transient frequency shift of a quasi-continuous single-mode frequency-doubled diode-pumped Nd:YAG ring laser has been measured using a confocal spherical Fabry-Perot. At a rate of 50 Hz, a quasi-linear shift of 5.4 MHz at the fundamental 1.06-/spl mu/m wavelength has been measured during the 150-/spl mu/s laser pulse duration. The doubled frequency, which is obtained by an intracavity LBO crystal, shows also a similar but doubled linear shift. This observed frequency shift is interpreted as due to thermal effects in the rod and fits well a modeling of the pulsed laser diode pumping. Introducing intracavity compensation, a piezoceramic transducer mounted cavity mirror, has limited the observed shift to less than /spl plusmn/1 MHz. Such a quasi-continuous Nd:YAG single-mode and frequency stabilized device should be a very suitable single-mode laser source to pump optical parametric oscillator systems.