Abstract: A method is disclosed for scribing a contained crack or vent in a chemically strengthened glass sheet. The glass has shallow surface regions under compressive stress, bounding a central region under tensile stress. The vent is formed by rapidly bulk-heating the glass, using radiation from a carbon monoxide laser, to a depth just below a surface compressive region and extending marginally into the tensile stress region then rapidly cooling the heated region with a water mist spray. The glass sheet can be subsequently divided along the vent by application of mechanical or thermal stress.

Abstract: A method is disclosed for scribing a contained crack or vent in a chemically strengthened glass sheet. The glass has shallow surface regions under compressive stress, bounding a central region under tensile stress. The vent is formed by rapidly bulk-heating the glass, using radiation from a carbon monoxide laser, to a depth just below a surface compressive region and extending marginally into the tensile stress region then rapidly cooling the heated region with a water mist spray. The glass sheet can be subsequently divided along the vent by application of mechanical or thermal stress.

Abstract: A non-linear optical device in which quasi-phase matching between different optical waves of differing polarizations and refractive indices increases the interaction length between the waves. The quasi-phase matching structure includes a periodic structure over which the non-linear coefficient varies with a given period, preferably the sign of the non-linear coefficient being inverted between two alternating regions. In LiNbO.sub.3, the periodic structure can be achieved by electrical poling. The required period length is increased by selecting light waves of different polarizations for the non-linear interaction such that a large portion of the dispersion between the waves of different wavelength is compensated by the birefringence of the waves of different polarization. In particular, periodic poling can quasi-phase match radiation in the range of 0.80 .mu.m to 1.2 .mu.m to generate second harmonic generation radiation in the blue and green visible spectrum.

Abstract: A laser system in which an intense laser beam of a predefined pumping wavelength traverses a non-linear material, such as crystalline lithium niobate, that has been impressed with one or more quasi phase matching (QPM) gratings is disclosed. Quasi phase matching compensates for the dispersion or birefringence in a non-linear material by modulating the non-linearity with the proper period such that the different wavelengths involved in the non-linear process stay in phase over a long interaction length. The first QPM grating promotes the parametric generation of a resonant signal whose wavelength is determined by the grating period. According to the invention, either a second QPM grating impressed in the same medium or a different order of the first QPM grating promotes the non-linear interaction between the resonant signal and another optical signal traversing the non-linear material.

Abstract: A laser system in which an intense laser beam of a predefined pumping wavelength traverses a non-linear material, such as crystalline lithium niobate, that has been impressed with one or more quasi phase matching (QPM) gratings is disclosed. Quasi phase matching compensates for the dispersion or birefringence in a non-linear material by modulating the non-linearity with the proper period such that the different wavelengths involved in the non-linear process stay in phase over a long interaction length. The first QPM grating promotes the parametric generation of a resonant signal whose wavelength is determined by the grating period. According to the invention, either a second QPM grating impressed in the same medium or a different order of the first QPM grating promotes the non-linear interaction between the resonant signal and another optical signal traversing the non-linear material.

Abstract: Methodology and apparatus for producing pulsed, single longitudinal mode optical energy over a widely tunable range of wavelengths by optical parametric frequency conversion.

Abstract: The operation of a .beta.-BaB.sub.2 O.sub.4 optical parametric oscillator is disclosed. The oscillator is tunable in the visible and near infrared. For example, a .beta.-BaB.sub.2 O.sub.4 crystal 10.5.times.10.5 nm.sup.2 .times.11.5 mm, cut at .theta.=30.degree. was pumped at 354.7 mm, and was tunable through 0.45-1.68 .mu.m, with a total energy conversion efficiency of 9.4%.

Abstract: A walkoff-compensated frequency conversion system such as an optical parametric oscillator includes a pair of nonlinear crystals, such as Beta-Barium Metaborate, aligned in an optical cavity with their optical axes at an angle .THETA. with respect to the axis of the cavity. The crystals are oppositely disposed with respect to the cavity axis so that the angle between their respective optical axes is 2.THETA.. In an optical parametric oscillator, the crystals are pumped to produce optical parametric luminescence and frequency conversion, the luminescence being emitted as signal and idler beams. The opposite arrangement of the optical axes of the crystals causes the pumping beam to walk off the signal beam in the first crystal and to walk on the signal beam in the second crystal. Similar walkoff compensation is provided in other frequency conversion systems wherein crystal pairs are oppositely disposed along a cavity optical axis.

Abstract: An optical parametric oscillator capable of operating in the 0.300 to 0.400 micrometer wavelength range is disclosed. The oscillator includes a cavity defined at its ends by a pair of cavity resonator mirrors. A nonlinear optical crystal is positioned on the optical axis of the cavity intermediate the mirrors and is rotatable about a crystalline axis to tune the oscillator. A pair of pump steering mirrors are mounted in the cavity, one mirror between each resonator mirror and the corresponding end of the crystal. A source of pumping energy supplies energetic light to the cavity, the pumping beam being directed into the cavity and onto a first steering mirror, thence through the crystal and to the second steering mirror which then directs the pumping beam out of the cavity. The pumping beam may be at a wavelength of 266 nm, for example, to produce an output wave from the oscillator within the range of interest.