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Continuous-wave UV radiation at 354 nm, the third harmonic of a Nd:GdVO4 laser operating at 1063 nm, is reported from single-pass cascaded, first-order periodically poled MgO:LiNbO3 (PPMgLN) crystals. A high-voltage multipulse poling method was used in order to realize PPMgLN with uniform domain period (Λ) of micron-order width and 50% duty cycle along the entire crystal length. Initially, second-harmonic generation of the 1063 nm Nd:GdVO4 laser at 2.1%/W conversion efficiency, producing 1.15 W at 531 nm, is obtained from a 10-mm-long PPMgLN with Λ=6.95 μm. Sum frequency mixing of this 531 nm light with the residual 1063 nm fundamental radiation in a 3.6-mm-long PPMgLN with Λ=1.78 μm produces 47 mW of UV with 3.9%/W/cm normalized conversion efficiency. [ABSTRACT FROM AUTHOR]

High-power continuous-wave (cw) operation of a diode edge-pumped microchip composite Yb:Y[sub 3]Al[sub 5]O[sub 12] (YAG) laser is reported. Up to 90 W were obtained from a 400-μm-thick Yb:YAG/YAG structure with a 10 at. % Yb:YAG square core of 2×2 mm[sup 2] area; the slope efficiency and optical-to-optical efficiency with respect to the pump power were 40% and 28%, respectively. Measurements of the optical phase distortions induced by pumping gives a focus shift bellow 0.05 m and shows the absence of astigmatic effects, indicating the axial heat flow in this pumping configuration. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The possibility of basic enhancement of the overall optical-to-optical efficiency of intracavity frequency-doubling devices for the 1 μm continuous-wave (cw) Nd lasers by direct pumping into the emitting level and by using concentrated laser materials is discussed. This possibility is demonstrated for 1.0 and 2.4 at. % Nd:Y[sub 3]Al[sub 5]O[sub 12] (Nd:YAG) crystals pumped by a Ti:sapphire laser at 885 nm. A slope efficiency of 0.79 in absorbed pump power was obtained for the 1064 nm emission of a 1.0 at. % Nd:YAG crystal. The effect of enhancement of intracavity emission on the second-harmonic emission is manifested in a drastic reduction of emission threshold and in an increased dependence on the absorbed power. The use of concentrated Nd:YAG crystal enables a better use of the pump power and improves the overall optical efficiency of the intracavity frequency-doubling devices. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Continuous-wave power of 189 mW at 473 nm with 49% conversion efficiency is generated from a 8.5 mm long uncoated periodically polled MgO:LiNbO[sub 3] ridge-type waveguide by frequency doubling of a diode end-pumped Nd:Y[sub 3]Al[sub 5]O[sub 12] laser at room temperature; the corresponding internal blue power and conversion efficiency were 222 mW and 58%, respectively. The highest conversion efficiency of 63% (74% with respect to the blue internal power) was obtained from a 12 mm long waveguide with 99 mW blue output power. Saturation of output blue power was observed for coupled fundamental power into the waveguides in excess of 200 mW. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

One-micron continuous-wave (cw) laser emission with 0.80 slope efficiency (0.79 optical-to-optical efficiency) under Ti: sapphire and 0.75 slope efficiency relative to absorbed power under diode-laser pumping at 880 nm into the emitting level is demonstrated in a 1-mm-thick, 1.0-at. % Nd:YVO[sub 4] crystal. These values are superior to those obtained with 809-nm pumping into the level [sup 4]F[sub 5/2], and can be explained consistently by the effect of the quantum defect between the pump and laser radiation, the superposition of pump and laser mode volumes, the pump-level efficiency and the residual optical losses. In the analysis of the 809-nm pumping data a pump-level efficiency equal to the unity was employed, as determined with a method based on the pump-saturation effects on absorption. [ABSTRACT FROM AUTHOR]