Abstract: A low-temperature Raman laser apparatus that avoids an increase in the pump light power, which would otherwise be needed under room temperature conditions, and eliminates the problems of instability of the equipment and complicatedness of the operation under liquid nitrogen cooling conditions and also lowers the cost, which has heretofore been high due to the consumption of liquid nitrogen, and that is capable of stably and efficiently effecting Raman conversion. The low-temperature Raman laser apparatus has a Raman cell (1) filled with a Raman conversion medium to convert the wavelength of incident pump light by the Raman conversion action of the Raman conversion medium. A heat absorbing member (2) or (3), through which a brine cooled by a brine refrigerator (4) circulates, is provided around the Raman cell (1) to cool the Raman conversion medium to a temperature in the range of from 200.degree. K. to 300.degree. K.

Abstract: An output control method for a laser system comprised of a laser oscillator and a laser amplifier. The method enables the output energy to be stably controlled over a wide range, without changing the excitation energy, by controlling the delay (.tau.) of the excitation energy application timing of the laser oscillator with respect to the excitation energy application timing of the laser amplifier.