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: The present invention encompasses an apparatus for pumping a vibronic laser, which comprises: a transition-metal ion-containing solid state vibronic laser gain medium; a means for exciting said laser medium to emit coherent radiation said exciting means being a pumping source comprising at least one laser diode operating at a wavelength shorter than 750 nm; and an optical resonator means for generating and controlling said coherent radiation. The present invention also encompasses a method of pumping a vibronic laser comprising the steps of: generating a laser diode pumping beam at a wavelength shorter than 750 nm; exciting a transition-metal ion-containing solid state vibronic laser gain medium by impinging said laser diode pumping beam on said transition-metal ion-containing solid state laser gain medium, so as to excite the laser medium; and an optical resonator to emit coherent radiation.

Abstract: Rotational displacement of the birefringent lasing medium in a lasing cavity containing a polarizing element varies the spectral width of the generated laser light. The combination in a lasing cavity of a birefringent lasing medium, a polarizing element, a tuning element and a birefringent compensator permits output of narrow bandwidth spectrally tuned laser light continuously over the total gain bandwidth of the lasing medium by rotating the lasing medium, tuning to desired wavelength, and adjusting the birefringent compensator to optimize output of laser light.

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 cell for holding a fluid medium for passing a beam of laser radiation through it to generate Raman shifted radiation is provided with a vaned agitator designed to effect flow of the fluid within the cell across the beam path, so that there is continually provided a fresh column of the optical medium within the beam path.

Abstract: Device for providing a train of light pulses at Raman shifted frequency comprises a first ring laser (for fundamental frequency) and a second ring laser (for Raman shifted frequency). Both ring laser intersect in a Raman laser medium which is common to the cavity of both ring lasers. The Raman cavity has output means partially transmissive at Raman frequency. Length of first and second ring laser cavities differs by .DELTA.L. Injection of a fundamental pump pulse and a small Raman seed pulse into their respective cavities results in output of a train of Stokes pulses.

Abstract: A partially-transparent, noble-metal protective overcoat is provided to a front-surface silver reflector. The overcoat, preferably of gold, may be applied by vacuum-deposition or electrodeposition. Optimum overcoat thickness is the minimum required to protect the reflector in the environment of its intended use. The overcoated reflector of this invention is particularly well suited for the surface of a laser pump cavity.

Abstract: A single crystal of rare-earth-doped lanthanum beryllate, whose crystal orientation is suitably chosen, provides a laser medium whose index of refraction is substantially independent of temperature. A laser using such a crystal as the laser medium displays little or no thermal lensing, thus permitting high power operation without wavefront distortion.

Abstract: A moire microscope comprises an objective lens, a collimating lens, and a pair of spaced-apart gratings arrayed along an optic axis and adapted for providing a magnified moire deflectogram of a phase object. The microscope provides a simple apparatus for preparing a map of optical thickness gradients, from which quantitative data concerning the object can be computed.

Abstract: Efficient multiphoton excitation is accomplished by sequentially exciting a polyatomic molecule with one or more wavelengths of infrared laser radiation. Preferably, the delay between successive excitations is longer than the rotational but shorter than the vibrational relaxation time of the molecule. By this method, laser-induced chemical reactions or isotope separation can be achieved with lower fluence and/or higher concentration of molecules than with prior art methods.

Abstract: Electronic excitation of polyatomic molecules followed by nonradiative decay provides states from which efficient multiphoton infrared excitation can be achieved. Initial (electronic) excitation can be molecule-specific or isotope-selective. Subsequent multiphoton excitation has a threshold which can be an order of magnitude or more lower than for multiphoton excitation from the ground state. By this method, laser-induced chemical reactions or isotope separation can be achieved with lower infrared laser fluence and/or higher concentration of polyatomic molecules than with prior art methods.