USA As Represented by Secretary of the Navy

Irwin Schneider

Philipp H Klein

William C Collins

Oscar Imber

Ishwar Dayal Aggarwal

Kenneth J Ewing

Gregory Nau

Charles S Guenzer

Thomas Bilodeau

Robert S Afzal

David R Foster

A refractive index-based sensor uses a light source and an optical fiber to direct an optical beam towards a sensor/environment face at a specific angle. The sensor has a predetermined shape selected such that the light directed into the sensor will have a specific angle of incidence designed to detect a plurality of liquids. A second optical fiber carries the light reflected off the sensor/environment face to a photodetector. The optical beam will either be transmitted through or reflected off the sensor/environment face based upon the refractive indices of the sensor and the environment and upon the angle of incidence of the optical beam. The amount of light reflected is indicative of the refractive index of the material in a given area of the sensor/environment face and, thus, the type of material. By adjusting the angle at which the light is directed to the sensor/environment face, the photodetector response can be calibrated to identify the type of liquid present at the sensor/environment face.

Refractive index-based sensor for the discrimination of chlorinated

A color center laser is provided with a crystal disposed within a longitudinally pumped cavity. Optics are provided to transversely excite the crystal. Both a circular lens and a cylindrical lens focus an auxiliary beam into the crystal of the color center laser to produce (F.sub.2.sup.+).sub.A color centers for lasing. The cylindrical lens is used to focus the auxiliary beam to a narrow focal line. The circular lens is used to adjust the length of the focal line. By adjusting the length of the focal line, an entirety of the pump beam is used for excitation. The lenses thus collimate and focus the focal line to a length within an active volume in the crystal of the color center laser essentially equal to a length of the crystal.

Color center laser with transverse auxiliary illumination

(F.sub.2.sup.+).sub.A color centers can be produced in additively-colored KI:Li or RbI:Li crystals provided that the material is colored in a nitrogen-free atmosphere. Copious (F.sub.2.sup.+).sub.A centers are produced in lithium-doped KI:Li or RbI:Li crystals using a procedure in which the crystals are grown, additively colored, and annealed in an argon ambient; and optically excited at successively-lower temperatures with a light of a wavelength readily absorbed by the crystal situated in a vacuum.

Method for forming copious (F.sub.2.sup.+).sub.A centers in certain

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.

Color center laser, material, and method of lasing

A polarimetric image recorder which records only the net polarization of the viewed scene. An optical lens system projects the light originating from the viewed scene onto a thin layer of an alkali halide crystal containing anisotropic color centers. Polarized light reorients the color centers and creates a net polarization in the layer. The net polarization of the layer is read by such means as shining polarized light through the layer and then through a polarizer set perpendicularly to the polarization of the light source. Whatever light is viewed through the reader represents a net polarization in the scene.

Polarimetric image recorder

The improvement of the electrolytic and additive methods of coloring alkali fluoride crystals comprising the step of selecting an alkali fluoride crystal having the impurities of between 0 and 5 ppmA of OH; between 0 and 50 ppmA of one or more alkaline earth cations, of which between 0 and 10 ppmA Mg.sup.++ and between 0 and 10 ppmA Ca.sup.++ ; between 0 and 50 ppmA of non-fluorine halide anions; between 0 and 10 ppmA of SiF.sub.6.sup.= ; between 0 and 30 ppmA of other ions; and the method of preparing these crystals which comprises converting the alkali fluoride to alkali hydrofluoride, crystallizing and vacuum drying the alkali hydrofluoride crystals, regenerating the alkali fluoride by expelling hydrogen fluoride, and crystallizing the alkali fluoride.

Photodichroic crystals

Broadly tunable, c.w. laser action in the ir(infrared) spectral region is obtained from (F.sub.2.sup.+).sub.A color centers in an alkali halide crystal having F.sub.A, F.sub.B, F.sub.A ', F.sub.B ' (F.sub.2).sub.A and (F.sub.2.sup.+).sub.A color centers in a dynamic equilibrium. The laser material is prepared by additively coloring an alkali halide crystal, exposing the colored crystal to light in the high-energy edge (i.e., between 450-300 nm) of the F-center absortion range at a temperature from about 253K to about 300K, cooling the crystal to a temperature not greater than 100K, and re-exposing the crystal to the same light to create a dynamic equilibrium state in which (F.sub.2.sup.+).sub.A centers are present.

Solid state laser and material

Photodichroic crystals and preparation thereof

A method of improving the holographic storage of data by yielding brighter olograms with higher densities which comprises recording an interferogram of an object wave and a reference wave into a holographically recordable medium consisting of an ionic crystal initially with a random distribution of anisotropic centers, and mutually off-set at an angle of at least sin.sup..sup.-1 10.lambda./d wherein d is the crystal thickness and .lambda. the wavelength of the coherent source; and then consecutively exposing the crystal to the object wave and the reference wave, each with a .pi./2 rotation in the plane of polarization but without any change in light intensity, wavelength, or crystal temperature.

Method for holographic storage

A method for determining the capability and optimum operating parameters of alkali halide crystals with anisotropic centers as holographic recording media by assessing the dispersion and absorption of polarized light by the anisotropic centers through a measurement of the difference in refractive index and absorption for light of different polarizations, the former through utilization of an ellipsometric technique wherein light passes successively through a polarizer, test crystal, analyzer, and detector.

Growing community of inventors

Alexandria, VA, United States of America

Irwin Schneider