This letter reports the CW red laser radiation at 659.5 nm by intracavity frequency doubling a side pumped Nd:YAG laser with a KTP crystal (type II phase match, Θ=59.8°, Φ=0°). The thermal lens effect related to the laser crystal is analyzed and parameters of the three-mirror folded cavity are calculated. To enhancing the high gain at 1319 nm of the operating wave of Nd:YAG, the reflectivity of the mirrors is designed, and the red laser radiation at 659.5 nm is achieved by intracavity frequency-doubling. The generation of 1.2 W of the CW red laser beam is obtained with 260 W pumped power.
High-power red laser are of great interest in the fields of medical application, laser display and also as a pumping source for tunable lasers such as Cr:LiSAF. This letter reports the generation of a 12W Q-CW red laser beam by intracavity frequency-doubling of a Nd:YAG laser operating at 1.3μm with a KTP crystal. A laser module that consisting of a Nd:YAG rod side-pumped by thirty 20W LDs of a triangle radial pump geometry, a acousto-optic Q switch and a KTP crystal were used in the experiment. Because the efficiency of SHG is sensitive to the type II phase-matching angles of KTP, we calculate the value of phase-matching angles according to several of Sellemier equations of KTP, and modify the phase-matching angles to θ=59.9° and φ=0° by experiment. The maximum average power of 12W of red laser is achieved at 10KHz when the pump power of LDs is about 470W.
We presented a diode end-pumped passively mode-locked Nd: YVO4 picosecond laser with a semiconductor saturable absorber mirror home made. Choosing a low-transmission output coupler and extending the cavity length suppressed the Q-switching mode-locked tendency in V-shaped cavity. We observed the pulse trains gone with a continuous background which was decreased with the decreasing of pulse repetition rate. The stable continuous mode-locked pulse was attained. The pulse repetition rate was 80.4MHz and the corresponding spectrum width was measured to be 0.15nm.