The advantages and potential hazards of using a planar waveguide as the host in a high-power diode-pumped laser system are described. The techniques discussed include the use of proximity-coupled diodes, double-clad waveguides, unstable resonators, tapers, and integrated passive Q switches. Laser devices are described based on Yb3+-, Nd3+-, and Tm3+-doped YAG, and monolithic and highly compact waveguide lasers with outputs greater than 10 W are demonstrated. The prospects for scaling to the 100 W level and for further integration of devices for added functionality in a monolithic laser system are discussed.

Greater than 12 W of average output power has been generated from a diode-pumped Yb:YAG cladding-pumped planar waveguide laser. The laser radiation developed is linearly polarized and diffraction limited in the guiding dimension. A slope efficiency of 0.5 W͞W with a peak optical -optical conversion efficiency of 0.31 W͞W is achieved. In a related structure, greater than 8 W of Q-switched average output power has been generated from a Nd:YAG cladding-pumped planar waveguide laser by incorporation of a Cr 41 :YAG passive Q switch monolithically into the waveguide structure. Pulse widths of 3 ns and pulse-repetition frequencies as high as 80 kHz have been demonstrated. A slope efficiency of 0.28 W͞W with a peak optical -optical conversion efficiency of 0.21 W͞W is achieved.

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Spatial walk-off can severely increase the threshold of critical phase-matched optical parametric oscillations (OPOs) and distort the output beam quality. With 16-layer KTP stacks for walk-off compensation, noncritical phase-match-like (NCPM-like) and quasi-phase-match-like OPOs with enhanced angular acceptance have been demonstrated based on two different KTP bonding orientations. In the NCPM-like composite, output pulse energy of 49 microJ has been achieved at pump energy of 523 microJ with pulse duration of 15 ns and repetition rate of 1 KHz. The OPO threshold as low as 254 microJ(44.6 MW/cm(2)) has been achieved.

Results achieved in high-precision molding of glass lenses are reported. The work concentrated on a 0.4- N.A. 8-mm diam lens with spherical surfaces. The glass is a specialty glass composition of index (d-line) 1.604 and Abbe number 50. Typical design tolerances which have been achieved in the molded glass lenses include relative surface figure replication of 0.06 Aim, thickness and diameter tolerances of A+/-10 Am, wedge of <10-3 rad, birefringence of less than one one-hundredth wave, and index homogeneity in the sixth decimal place. These results are directly applicable to molding precision glass aspheric lenses of similar tolerances.