Long‐pulsed Nd:YAG frequency‐doubled laser for optical measurements of high‐velocity phenomena

A long‐pulsed neodymium‐doped yttrium aluminum garnet (Nd:YAG) frequency‐doubled laser with no Q‐switch was constructed for optical measurements of high‐velocity phenomena. The laser consists of a doubled‐elliptical pump cavity with a Nd:YAG rod and two xenon flash lamps, an intracavity potassium titanyl phosphate crystal, and a high‐voltage electrical‐pulse source. A narrow‐band‐stimulated emission at the frequency‐doubled 532‐nm wavelength was confirmed by a spectrometer. The delay time from a trigger signal and the effective pulse duration were approximately 40 and 65 μs, respectively. The laser average output power was measured to be larger than 6 kW by a pyroelectric joulemeter. This laser may be used as a flash monowavelength light source, and also as a long‐pulsed single‐mode laser in the visible wavelength region using for example, an intracavity etalon and/or a brewster plate.