Abstract: A passive laser Q-switch is fabricated from a crystal which can form saturable color centers, such as lithium fluoride. The arbitrarily long crystal is irradiated with electrons from the side, or radially, to impart a radial distribution of saturable color centers therein, with the highest density at the periphery of the crystal. Optionally, the crystal can also be irradiated axially with electrons or in any direction with another form of radiation having greater penetration into the crystal, such as gamma radiation, to establish a base level of saturable color centers throughout the crystal. The crystal having the radial distribution of color centers acts as a Q-switch, but additionally tends to reduce beam divergence and increase the brightness of the laser beam by virtue of the nonlinear bleaching mechanism.

Abstract: An optical recording device includes a crystal selected from the group of alkali metal halides or alkali-earth halides and is doped with an alkali metal dopant and negative hydride ions to form a doped crystal. The doped crystal is formed to have a hydride light absorption band centered about a predetermined frequency and a color center light absorption band centered about another predetermined frequency. The doped crystal exhibits two switching states with the first state having a predetermined light absorbance level in the hydride band and a relative low light absorbance level in the color center band relative to the other state and a second state having generally the same absorbance level in the hydride band and a relatively high light absorbance level in the color center band relative to the first state.

Abstract: A laser device is disclosed having mirror heating to enhance performance of the device by minimizing induced light absorption to thereby improve mirror quality. The mirrors of a laser device are commonly made of a substrate having a coating thereon formed by alternating layers of high and low refractive index materials, normally classified as refractory oxide materials, which materials are susceptible to formation therein of color centers, such as formation of F-centers when exposed to ultraviolet light, which color centers reduce mirror quality due to induced light absorption losses. By heating the mirror, the F-centers are substantially eliminated to thereby improve mirror quality and enhance the longevity of the laser device.

Abstract: The electro-optical method described herein provides adjustable voltage dependent optical properties of a solid whereby the characteristics, i.e., the optical response to applied voltage, are separately adjustable for different laser frequencies. The solid has photo-absorbing centers capable of displaying persistent spectral hole burning; the spectral holes are capable of exhibiting electric-field induced filling. The main fields of application for this method are in integrated optics, image processing, and optical data storage.

Abstract: Stable color centers capable of laser emission in the near infrared region of the optical spectrum are provided in alkali halide host crystals containing monovalent heavy metal cation impurities such as thallium, gallium, indium, silver and copper. The laser active color centers are formed by exposing the crystal to ionizing radiation followed by irradiation with light having a wavelength absorbed by the F centers. The resulting material is capable of stable, broadly tunable laser operation with high power output in the near infrared region. Oscillation on a single mode can be easily obtained.

Abstract: A fluid cooled neodymium phosphate glass impulse laser comprising a passive release circuit. The laser may be designed with reduced size so as to be portable and is mainly used in medicine particularly for eye operations, in spectroscopy, in cosmetics, teaching and microtechnology. The proposed laser comprises a resonator of small size having a fluid cooled laser body and which may be disassembled without detuning the resonator, a closed cooling circuit, a supply unit of small size and low consumption and an electronic circuit. The resonator comprises a thick passive release composed of a F/2 center-colored LiF crystal and having a characteristic passive transmission power of 70%, a high reflection coefficient mirror and a partially reflecting output mirror having a characteristic transmission of 60%. The active material is composed of a phosphate glass bar of small diameter, generally 3mm, having a high concentration of Nd ions, generally from 1.2 to 1.4.times.10.sup.21 ions/cm.sup.3.

Abstract: A diamond (10) containing H3 and N3 color centers is employed as a laser active material in a color center laser. When excited by a suitable optical pumping source (22), the H3 color centers exhibit laser action and provide a beam (26, 28) which is tunable over the range of 500 to 600 nanometers.

Abstract: Vibrational emission from molecular defects in ionic crystals can be realized by dilute diatomic molecular defects such as, e.g., CN.sup.- molecules in alkali halide crystals. After association of F-centers to the CN.sup.- molecules, forming a new F-center/molecular defect pair, the emission can be pumped by optical F-center excitation through electronic-vibrational coupling. Using this coupling mechanism, laser action in the near infrared wavelength region is obtained between vibrational energy levels of the molecules while pumping the F-center/molecule defect in the visible wavelength range. The laser crystals are prepared by additively coloring a CN.sup.- doped alkali halide crystal and exposing the colored crystal to light having a wavelength capable of being absorbed by the electronic F-center/molecule defect transition.

Abstract: A laser material for a solid state tunable laser comprises a potassium or rubidium halide crystal with lithium and/or sodium cation impuritites in a crystalographic structure with point defects consisting essentially of F.sub.2.sup.+ and (F.sub.2.sup.+).sub.A color centers and electron traps. The crystals are colored both additively and with ionizing radiation.

Abstract: A method of achieving inversion in solid-state rare-earth materials for blue-green laser operation. A XeF excimer laser is used to pump a matching transition in divalent ytterbium in a host material. The host material is co-doped with a trivalent ion such as praseodymium (Pr.sup.3+) so that energy transfer to the trivalent ion will take place. Laser action is then from the Pr.sup.3+ ion. Alternative matching absorption transitions also occur in the trivalent rare-earth ions of Tb, Dy, Ho, and Nd.