Tunable dye laser pumped by a frequency-doubled high-power cw Nd:YAG laser

Abstract

In the past, researchers have pointed out the advantages of using frequency-doubled Nd:YAG lasers rather than ion lasers as a pump source for tunable dye laser oscillators and amplifiers. However, operation of these systems has been restricted to either pulsed (Q-switched) or cw mode-locked regimes (or a combination of both). In this paper we present for the first time to our knowledge a nonmode-locked cw dye laser, pumped by a high-power frequency-doubled cw Nd:YAG laser. The latter is a commercially available cw laser (YAG rod: 76 × 4 mm), which has been modified for efficient intracavity frequency doubling by means of a KTP crystal. The green output beam is characterized by a nearly TEM00 profile, and a good temporal stability (both short term and long term). The dye laser has a three-mirror folded cavity design with a jet as the gain medium (rhodamine 590, in ethylene glycol). The overall characteristics of the system, such as stability, efficiency, and tunability are outlined, together with some of its potential applications (e.g., in ophthalmology). Compared with similar ion laser pumped systems, our system provides the additional advantages of increased ruggedness and reliability. It is also more user friendly and more cost-effective since it requires less maintenance, thereby reducing the shutdown time.