Abstract: An optic produces a beam of ultraviolet laser radiation from a beam of visible laser radiation and spatially separates the ultraviolet laser beam from the visible laser beam. The optic includes two crystals made of the same optically-nonlinear material that are contact bonded along a planar interface. One crystal has principle crystal axes that are oriented for type-I second-harmonic generation. The ultraviolet laser beam exits the optic through an uncoated surface of the other crystal. The principle crystal axes of the two crystals have different orientations and have reflection symmetry about the planar interface.

Abstract: An optic produces a beam of ultraviolet laser radiation from a beam of visible laser radiation and spatially separates the ultraviolet laser beam from the visible laser beam. The optic includes two crystals made of the same optically-nonlinear material that are contact bonded along a planar interface. One crystal has principle crystal axes that are oriented for type-I second-harmonic generation. The ultraviolet laser beam exits the optic through an uncoated surface of the other crystal. The principle crystal axes of the two crystals have different orientations and have reflection symmetry about the planar interface.

Abstract: An optical ring-resonator converts visible wavelength radiation to ultraviolet wavelength radiation by frequency-doubling the visible wavelength radiation in an optically nonlinear crystal. The resonator includes an uncoated birefringent out-coupling prism. The visible wavelength radiation passes through faces of the prism at a Brewster-angle. Ultraviolet wavelength radiation enters the prism, is totally internally reflected, directed out of the prism at a Brewster-angle, and exits the ring-resonator as output radiation.

Abstract: Optical apparatus for performing a frequency-conversion operation on laser-radiation includes three elongated optically nonlinear crystals arranged end-to-end on a propagation-axis of the laser-radiation. Each of the crystals is arranged to perform the same frequency-conversion operation. The length of the crystals is made progressively shorter in the propagation-axis direction.

Abstract: An electro-optic modulator for a laser beam includes an yttrium vanadate crystal cooperative with a double-pass electro-optic switch. A beam to be modulated passes through the yttrium vanadate crystal and makes a forward and a reverse pass through the electro-optic switch. The electro-optic switch returns the beam to the vanadate crystal selectively in one of two polarization orientations at 90 degrees to each other. Depending on the polarization orientation, the returned beam is transmitted by the crystal along a corresponding one of two about-parallel paths spaced apart from each other.

Abstract: A Q-switched solid-state laser has a neodymium-doped yttrium vanadate single-crystal gain-element in the form of a prism. The prism incorporates the functions of a gain-element, a polarizer, a resonator end-mirror and an output coupler.

Abstract: An electro-optic modulator for a laser beam includes an yttrium vanadate crystal cooperative with a double-pass electro-optic switch. A beam to be modulated passes through the yttrium vanadate crystal and makes a forward and a reverse pass through the electro-optic switch. The electro-optic switch returns the beam to the vanadate crystal selectively in one of two polarization orientations at 90 degrees to each other. Depending on the polarization orientation, the returned beam is transmitted by the crystal along a corresponding one of two about-parallel paths spaced apart from each other.

Abstract: A frequency-doubled OPS-laser having a desired output wavelength of 532 nm is tunable about that wavelength by a temperature tuned birefringent filter (BRF). The temperature of the BRF is varied while measuring transmission of a sample of the output through a Nd:YAG crystal having an absorption peak at a wavelength of about 532.4 nm. The peak is detected as a minimum of transmission and the temperature at which that minimum occurs is recorded. From wavelength-change-versus-temperature data for the BRF a temperature is calculated at which the output wavelength has the desired value and is maintained at that value to stabilize the output wavelength.

Abstract: A frequency-doubled OPS-laser having a desired output wavelength of 532 nm is tunable about that wavelength by a temperature tuned birefringent filter (BRF). The temperature of the BRF is varied while measuring transmission of a sample of the output through a Nd:YAG crystal having an absorption peak at a wavelength of about 532.4 nm. The peak is detected as a minimum of transmission and the temperature at which that minimum occurs is recorded. From wavelength-change-versus-temperature data for the BRF a temperature is calculated at which the output wavelength has the desired value and is maintained at that value to stabilize the output wavelength.

Abstract: A two-resonator laser arrangement for provides visible-wavelength radiation by sum-frequency mixing two different wavelengths of radiation circulating in the resonators in an optically nonlinear crystal located in the resonators. One of the resonators includes a solid-state gain-medium providing of one the two wavelengths and the other resonator includes a semiconductor gain-medium providing the other of the two wavelengths. A very short excited-state lifetime of the semiconductor gain-medium provides that noise and instability commonly encountered in the output of prior-art intra-resonator frequency-converted lasers is substantially reduced.

Abstract: A method for generating ultraviolet radiation includes sum-frequency mixing in one optically nonlinear crystal fundamental-wavelength radiation generated by a Pr:YLF gain-element with radiation having a second-harmonic wavelength of fundamental-wavelength radiation generated by a Pr:YLF gain-element. The second-harmonic wavelength is generated in another optically nonlinear crystal. The fundamental-wavelength radiation being mixed and the fundamental wavelength radiation from which the second-harmonic radiation is generated may have the same wavelength or different wavelengths.

Abstract: Red light and green light are generated by passing a beam of plane-polarized blue light sequentially through two resonators each including a praseodymium-doped gain medium. A portion of the blue light is absorbed in the gain media and optically pumps the gain-media. Green light is generated in the first resonator and red light is generated in the second resonator. Green light from the first resonator is transmitted through the second resonator. Red light, green light, and unabsorbed blue light are delivered from the second resonator. Relative proportions of red light, green light, and blue light delivered from the second resonator can be varied by varying the orientation of the polarization-plane of the blue light with respect to the gain media. Sources of plane polarized blue light include optically pumped, frequency-doubled edge-emitting and surface-emitting semiconductor lasers.

Abstract: Red light and green light are generated by passing portions of a beam of plane-polarized blue light through two resonators each including a praseodymium-doped gain-medium. One of the resonators generates green light and the other resonator generates red light in response to absorption of the blue light by the gain-medium. The amount of green or red light generated can be varied by varying the orientation of the polarization-plane of the blue light with respect to the gain-medium. The red light, green light, and a portion of the blue light not absorbed by the gain-media can be combined to form a beam of white light, or a beam of light of a predetermined color.

Abstract: A laser-resonator includes a praseodymium-doped crystal gain-medium optically pumped by plane-polarized blue light delivered by a frequency-doubled, external cavity, surface-emitting semiconductor laser. The laser-resonator generates fundamental radiation at one of several possible wavelengths between about 500 nm and 750 nm. The fundamental wavelength generated is determined by a wavelength-selective element located in the laser-resonator and the polarization-orientation of the blue light relative to the c-axis of the crystal gain medium. An optically nonlinear crystal located in the laser-resonator frequency doubles the fundamental radiation to provide ultraviolet radiation.

Abstract: An intracavity frequency-doubled laser has a standing-wave resonator including a gain medium and an optically-nonlinear crystal. The optically-nonlinear crystal has a large walkoff-angle between the fundamental laser-beam and the frequency-doubled beam created by passage of the fundamental laser-beam through the crystal. The optically-nonlinear crystal is arranged such that the walkoff-angle provides for lateral, spatial separation of a fundamental and a corresponding frequency-doubled beam outside the crystal, and for separation of counterpropagating frequency-doubled beams from each other. The spatial separation of the counterpropagating frequency-doubled beams reduces amplitude fluctuation caused by interference between the beams. A physical stop is used to prevent one of the frequency-doubled beams from entering the gain medium. This prevents that beam from spuriously pumping the gain medium and thus serves to further reduce amplitude fluctuation.

Abstract: Module-forming component secured to a substrate using heat activated bonding arrangements are made by resistance heating the bonding medium, for example solder, thermal activated adhesive or thermoplastic material, using electrically energized resistance elements, for example thick film resistance layers, secured to the side of the substrate opposite the side on which the components are secured.

Abstract: A method for bonding a component (14) to a substrate (18) via a thermally hardened or softened bonding medium, employs PTC or NTC thermistor (24) for heating the bonding medium during bonding of the component. In one disclosed example, the method is used for bonding an optical fiber to a substrate, via a solder layer (40), in alignment with a semiconductor laser (12) in a diode-laser module (10).

Abstract: In order to produce higher harmonics more efficiently in a laser having a first optically nonlinear crystal acting as a frequency doubler, and at least one further optically nonlinear crystal acting as a frequency multiplier disposed behind the first nonlinear crystal in the direction of propagation of laser radiation produced by the laser, the first to second-to-last optically nonlinear crystals are selected to each have a walk-off angle in the range of 0.1.degree. to 6.degree., and all of the optically nonlinear crystals are disposed relative to one another in such a way that the plane of the principal section of one crystal contains a direction of small angular acceptance with respect to phase matching of a following crystal.