Abstract: Tunable optical parametric amplifiers and oscillators that are pumped by the light from a tunable laser source are disclosed. One possible embodiment uses a tunable solid-state laser pump and an OPA medium or nonlinear crystal, such as potassium titanyl phosphate KTP or barium borate BBO or lithium borate LBO. The second harmonic output from a tunable solid-state laser is also used to pump the OPA medium. A singly or doubly resonant cavity design is preferably used to reduce the oscillation threshold (i.e., the required pump beam power) of the OPO.

Abstract: A method of laser lithotripsy is disclosed that utilizes pulse stretched Q-switched solid state lasers in conjunction with relatively small diameter optical fibers to achieve effective breakup of calculi located within the body, such as kidney and gall stones.

Abstract: A laser beam from a tunable solid state laser such as an alexandrite laser passes through a Raman shifter to produce a Raman-emitted beam with wavelength shifted so as to be able to activate a preselected photosensitizer for medical treatment. A combination of a laser and a Raman shifter with or without additionally a harmonic generator such as a frequency doubler may be also selected such that radiation with two different wavelengths can be obtained for treatment and detection.

Abstract: A broadly wavelength-tunable laser is provided which comprises as the laser medium a single crystal of YGG:Cr.sup.3+. The laser may be operated over a broad temperature range from cryogenic temperatures to elevated temperatures. Emission is in a spectral range from red to infrared, and the laser is useful in the fields of defense, communications, isotope separation, photochemistry, etc.

Abstract: A high power, broadly wavelength-tunable laser is provided which comprises as the laser medium particular single crystals of chromium-doped beryllium aluminate (BeAl.sub.2 O.sub.4 :Cr.sup.3+) having the chrysoberyl structure, means for exciting the laser medium and tuning means. The laser may be operated over a broad temperature range from cryogenic temperatures to elevated temperatures. Elevated temperatures are preferred, however, since they result in higher laser gain. Emission is in a spectral range from red to infrared, and the laser is useful in the fields of defense, communications, isotope separation, photochemistry, etc.CROSS-REFERENCE TO PRIOR APPLICATIONThis application is a continuation-in-part of application Ser. No. 953,067, filed Oct. 20, 1978.