Abstract: Apparatus for color grading of liquid or solid products, such as fruits, vegetables, etc., said apparatus employs an electronic device which measures the ratio of reflectance of the products at two separated parts of the light spectrum. The device views either a calibration surface or the product being tested so that between tests the operator can see whether or not the instrument is holding its calibration and adjust it if necessary.

Abstract: A crystalline optical convertor, adapted to improve the efficiency of a resonant cavity of a laser cavity system, includes: neodymium ions used as lasing ions, a host for the neodymium ions which is used as a laser rod, convertor ions, and a crystalline convertor host. The convertor ions are selected from the group consisting of trivalent dysprosium and trivalent samarium. The crystalline convertor host is selected from the group consisting of: yttrium orthovanadate, yttrium phosphate, yttrium arsenate, yttrium chromate, gadolinium orthovanadate, gadolinium phosphate, gadolinium arsenate, gadolinium chromate and combinations thereof in solid solution. The convertor ions act as an activator for the crystalline convertor host. The combination of neodymium ions and neodymium host is arranged separate from the combination of the convertor ions and the convertor host.

Abstract: The compound Tl.sub.3 PSe.sub.4 is disclosed. Non-conducting single crystals of the compound are prepared which have outstanding acousto-optical properties including an exceptionally high acousto-optical figure of merit. The crystals are used in various acousto-optical devices including a display device, a laser modulator, a non-collinear acousto-optical filter, and an acoustic delay line.

Abstract: A semiconductor laser device includes a narrow elongated semiconductor region of the same conductivity type as another semiconductor region lying in the vicinity of the active region of the laser device. The elongated region extends in depth from the surface of the device to the vicinity of the active region. A surface semiconductor layer of an opposite conductivity type covers the entire surface of the device except for the elongated region.

Abstract: A method for controlling the population inversion in a solid state laser material by optically pumping the material with a laser beam having a wavelength corresponding to the absorption band of the laser material and the output of which is spatially and temporally modulated. Spatial and temporal modulations of the population inversion in the pumped material are achieved by means of a two-dimensional spatial modulator positioned between the pump laser beam and the pumped laser material, the modulation being thermo-optically controlled by a scanning electron or laser beam or electro-optically controlled by a scanning electron beam or acousto-optically controlled by a two-dimensional acousto-optical modulator. Utilization of a lens between the spatial modulator and the optical cavity of the laser material permits electronic deflection of the output from said laser material by focusing the beam transmitted through said spatial modulator.

Abstract: A laser cavity containing a mixture of nitrogen, N.sub.2, and mercury, Hg, gas is optically pumped by a lamp containing mercury to produce a laser output of 546.1 nm. The upper laser level is excited through optical pumping by a resonance lamp while the lower level which is a low lying metastable state is depopulated by collisional quenching.

Abstract: A two-dimensional dye laser scanning system is provided wherein a dye laser having a controlled output wavelength is combined with a diffractive beam-bending device to produce a near infrared or visible laser beam that can be directed to scan in two orthogonal planes at 100 MHZ rates.

Abstract: There is disclosed a gaseous laser, whose cathode is a conductive coating upon the walls of a cathode volume, the geometric design of the cathode, cathode volume, and cathode-connecting volume being such as to impede sputtering of the cathode.

Abstract: The lasing species of CS(a.sup.3 .pi.) and CSe(a.sup.3 .pi.) are produced by reacting atomic carbon and COS or COSe in an inert medium such as helium, argon, nitrogen, etc.

Abstract: A nematic liquid crystal device for electro-optical display devices, is provided. Its long-shaped molecules are orientated perpendicularly to the electrode plates delimiting the crystalline liquid, i.e. homeotropically aligned. A polymer layer with long-chain molecules has been previously formed on the internal faces of each plate separately arranged on a discharge electrode of an electrical apparatus operating at high frequency (13.56 mc/s) and containing a vapour at very low pressure of a monomer such as hexamethyldisiloxane. The molecules of polymer thus formed are perpendicular to the plates and a similar orientation of the liquid crystal molecules result from that, i.e. a homeotropic alignment.

Abstract: In a laser system activated by a molecular gas there is provided a novel nozzle construction for the purpose of effecting expansion of the gas in a minimum period of time but without destroying laminar flow conditions therein. Instead of the relatively long single nozzle of the prior art there is provided a plurality of nozzles expanding in three dimensional directions and arranged in parallel aligned relationship in a cluster closely adjacent each other. The nozzles may be of many cross-sectional shapes but in one embodiment the walls are concave, such that a relatively large wall angle with respect to the direction of flow at the throat of the nozzle diminishes progressively toward the end of the nozzle so that at such end the nozzle walls will be substantially parallel with each other, whereby to discharge the gas stream therefrom in a jet of constant cross-sectional area.

Abstract: A laser assembly that includes a novel glass laser disc having an annular alkali lead borate glass coating for use in the assembly is disclosed. The annular coating has an index of refraction that is about 3 to 12% greater than the index of refraction of the laser disc, the thermal properties also being sufficiently matched with the glass laser disc so as to prevent the development of undesirable strains therein, the glass coating comprising a mixture of alkali metal oxides in which at least two different alkali metal oxides are present, and any K.sub.2 O that is present is limited to an amount of not substantially more than about 1% by weight and an effective energy absorbing amount of heavy metal oxide that absorbs energy at a wavelength of about 1.06 microns to prevent parasitic oscillations. The heavy metal oxides include oxides of transition metals of the 3d, 4d, 4f, 5d and 5f orbital series.

Abstract: A continuous wave chemical laser device in which useful species such as free radicals as vibrationally excited molecules are generated by interaction of suitable chemicals such as hydrogen, sulfur hexafluoride, and carbon dioxide with laser radiation. The chemical laser device is capable of generating active species by interaction of its own laser radiation after first being initiated by a suitable initiator. The chemical reactions involved can take place at atmospheric pressure or higher and overcome disadvantages of ordinary chemical lasers.

Abstract: A miniature TEA laser system having a pair of electrodes mounted within the laser cavity and a radioactive source in the form of a beta particle emitter located within the cavity adjacent the electrodes. The electrodes are spaced no more than the maximum beta particle range apart so that the radioactive emission can take place within the space between electrodes thereby uniformly preionizing the active laser medium within the cavity.

Abstract: The inventive laser comprises two identical hollow nozzle portions which are positioned in layered fashion (i.e., in stacked condition), in registration, and with their respective longitudinal axes in parallel. Each nozzle portion has a protrusion extending into the void or hollow interior, and coolant flow passages are located in the protrusion. The internal surface of each nozzle portion has a nickel fiber wick sintered to it, and the wick is saturated with a metal, preferably sodium, which is in a liquid state. The unique structure of the inventive nozzle permits a very short transient start and also permits operation of the nozzle at steady-state conditions in an isothermal manner.

Abstract: Method for producing continuous wave chemical laser output in which useful species such as free radicals as vibrationally excited molecules are generated by interaction of suitable chemicals such as hydrogen, sulfur hexafluoride, and carbon dioxide with initiator laser radiation. The chemical laser output is sustained by feeding back a portion of the laser output after first being initiated by a suitable initiator. The chemical reactions involved can take place at atmsopheric pressure or higher and overcome disadvantages of ordinary chemical lasers.

Abstract: Articles are described which utilize a unique photochemical property of a certain class of heterocyclic compounds. These heterocyclic compounds are the mono- and bicyclic aziridines. Oriented crystals of these heterocyclic compounds are photochromic in an unusual way. The effect of the excitation radiation and the strength of the resulting absorption band responsible for the appearance of color depend on the polarization of the radiation. These articles contain at least one optically smooth surface. Typical articles are windshields or glass panes which darken on being exposed to glare and sunglasses. Switching devices are also described which exist in two states; one state characterized by absorption of certain radiation over wavelength range and the other state by high transparency.

Abstract: This device includes an expander open cycle gas dynamic laser wherein the majority of the gas dynamic laser flow is recirculated while a fraction of the flow is removed in a boundary layer bleed removal system. This device includes a combustor for providing the proper gas constituents which then flow downstream of a nozzle means in a laser cavity to permit lasing to occur. The flow from the lasing cavity is directed into a diffuser which in turn directs its flow into the inlet of a compressor after flowing over a heat exchanger which cools the flow. One heat exchanger is in the bleed flow while the other is in the flow from the diffuser. The flow from the compressor is directed into the combustor.

Abstract: A tunable laser includes a birefringent tuning crystal placed in the laser cavity. An electrical signal is applied to the tuning crystal to establish an electrical tuning field within the crystal, and a desired laser tuning rate as a function of the applied electrical signal is established by rotating the optic axis of the crystal through a selected small acute angle from the direction of the laser light path through the crystal. The tunable laser is included in tunable laser systems for derivative spectroscopy and transient spectroscopy.

Abstract: A method of producing a lasable gaseous mixture for use in and operation of electron beam-sustainer carbon dioxide lasers comprising burning a hydrocarbon fuel to produce substantially oxygen free products of combustion, removing undesirable constituents to leave a gaseous mixture which can support laser oscillation comprising substantially only carbon dioxide, nitrogen and hydrogen, collecting the resulting gaseous mixture, and thereafter supply and use it as the active medium in an electron beam-sustainer laser.