Abstract: Disclosed is a non-linear optical material represented by the following formula: ##STR1## wherein X represents a methyl group or a hydrogen atom, with the proviso that when X is a methyl group, A represents a nitrogen atom, Y represents a methyl group and B represents a nitrogen atom; and when X is a hydrogen atom , A represents C--COOC.sub.2 H.sub.5, Y represents a hydrogen atom and B represents C--CH.sub.3.In one embodiment, the non-linear optical material is represented by the following formula (I): ##STR2## In another embodiment, the non-linear optical material is represented by the following formula (II): ##STR3## Also disclosed is an orthorhomic molecular crystal having a space group of Pna2.sub.1 and constituted by molecules represented by the above formula (I).

Abstract: A laser-diode-pumped solid-state laser includes a semiconductor laser for emitting a pumping laser beam, a solid-state laser crystal of an ion crystal of a paramagnetic substance doped with neodymium, for producing a laser beam in response to being pumped by said pumping laser beam, a resonator for oscillating the laser beam produced by said solid-state laser crystal, and an optical wavelength converter in said resonator for converting the wavelength of the oscillated laser beam into another wavelength. The solid-state laser crystal has a neodymium ion concentration higher than 3 at %. The solid-state laser oscillates stably in a single longitudinal mode at all times to produce a highly intensive laser beam of short wavelength.

Abstract: An optical wavelength converting apparatus comprises a semiconductor laser, which is capable of oscillating in a multiple longitudinal mode, and an external resonator for resonating a laser beam, which has been radiated out of the semiconductor laser and which serves as a fundamental wave. An optical wavelength converting device is located in an optical path of the fundamental wave, which has been resonated by the external resonator. A device feeds part of the fundamental wave, which has been resonated by the external resonator, back to the semiconductor laser. A wavelength-converted wave in a single longitudinal mode is thereby obtained, which wave has a high intensity and is stable.

Abstract: A method of forming a color image on a silver halide color photographic light-sensitive material having at least one silver halide emulsion layer provided on a reflective support, which does not substantially contain silver iodide and which contains silver chlorobromide or silver chloride grains having a silver chloride content of at least 95 mol %, said grains containing at least one metal ion consisting of a group of ions of metals of Group VIII of the Periodic Table, transition metals of Group II of the Periodic Table, lead and thallium in an amount of at least 10.sup.-9 mol per mol of silver halide, comprising exposing said photographic material by means of a scanning exposure using an image signal formed by scanning an original image and thereafter continuously processing said photographic material with a color developer substantially not containing benzyl alcohol, wherein the amount of the replenisher to the developer is 200 ml or less per m.sup.2 of the photographic material processed thereby.

Abstract: An optical wavelength converter system which has a crystal of a first nonlinear optical material for converting an incoming laser beam into a second harmonic wave and a crystal of a second nonlinear optical material for converting the laser beam and the second harmonic wave into a sum frequency wave. A phase compensator plate is interposed between the crystal of the first nonlinear optical material and the crystal of the second nonlinear optical material, whereupon the laser beam and the second harmonic wave are aligned substantially in the same linear polarization before they enter the crystal of the second nonlinear optical material.

Abstract: In an optical wavelength converting apparatus, a laser beam serving as a fundamental wave and having been obtained by pumping a solid laser medium is caused to impinge upon a nonlinear optical crystal, and the type II of phase matching between the fundamental wave and its second harmonic is effected. The second harmonic of the fundamental wave is thereby radiated out of the optical wavelength converting apparatus. A solid laser medium, which produces a linearly polarized fundamental wave in two longitudinal modes, is employed as the solid laser medium. A device for adjusting a difference in phase of the fundamental wave due to the nonlinear optical crystal and a device for adjusting the temperatures of the nonlinear optical crystal and a resonator, such that the temperatures may be kept at predetermined values, are provided in order to work such that two directions of polarization of the fundamental wave may intersect approximately perpendicularly to each other and may respectively incline approximately 45.

Abstract: There is disclosed an optical frequency converter of a bulk resonator structure comprising a ring resonator or V-shaped resonator made of a nonlinear optical crystal. The converter is equipped with a means for returning a laser light emitted by a semiconductor laser resonating inside the resonator to the semiconductor laser. The ring resonator or V-shaped resonator is made small in size and compact. The converter is insusceptible to vibration and needs no adjustment. Returning laser light is produced at less locations. The loss of the output light inside the resonator is reduced. The second harmonic is generated at a high efficiency. Multiple reflection is produced inside the resonator to further enhance the efficiency of the generation of the second harmonic of the laser radiation. Also, the phase of the radiation can be made uniform. The optical density can be increased.

Abstract: A nonlinear optical material comprising a compound represented by the following general formula (I): ##STR1## wherein R and R' are each an alkyl group, an aryl group, an aralkyl group or a hetero ring, and a method of converting the wavelength of laser light using the organic nonlinear optical material.

Abstract: An optical wavelength converting device comprises an optical waveguide device. The optical waveguide device is provided with a waveguide, which is constituted of a solid laser medium doped with a rare earth metal and a nonlinear optical material for converting a wavelength. The solid laser medium and said nonlinear optical material are overlaid one upon the other. A cladding is formed of a material having a lower refractive index than the waveguide and accommodates the waveguide therein. Two edge faces of the optical waveguide device serve as a resonator for a laser beam, which has been produced by the solid laser medium.

Abstract: A laser-diode-pumped solid-state laser includes a solid-state laser rod pumped by a pumping laser beam emitted from a semiconductor laser. The laser beam produced by the solid-state laser rod is oscillated by a resonator, and the wavelength of the oscillated laser beam is converted into another wavelength by an optical wavelength converter. The resonator is jointly provided by the solid-state laser rod and the optical wavelength converter. Alternatively, the solid-state laser rod may comprise a self-frequency-doubling crystal for producing a laser beam, oscillating the laser beam, and converting the wavelength of the oscillated laser beam into another wavelength. The temperature of the semiconductor laser and the resonator is regulated by a common temperature regulating device which comprises a Peltier device controlled by a driver circuit.

Abstract: An optical wavelength conversion method employs a bulk-crystal-type optical wavelength converter device of a single crystal of nonlinear optical material known as PRA. Linearly polarized fundamental waves whose wavelengths range from 450 to 4,000 nm are applied to the bulk single crystal, and angle phase matching of the type I is achieved, thereby producing a wave whose frequency is the sum of the frequencies of the applied fundamental waves. A laser-diode-pumped solid-state laser includes a solid-state laser rod doped with a rare-earth material such as neodymium or the like and pumped by a semiconductor laser, and a bulk single crystal of organic nonlinear optical material disposed in a resonator. The bulk single crystal converts the wavelength of a laser beam which is oscillated by the solid-state laser rod and the wavelength of a pumping laser beam into the wavelength of a wave whose frequency is the sum of the frequencies of the laser beams.

Abstract: A method of forming colored images by exposing and then developing a silver halide color photographic photosensitive material which has a blue sensitive silver halide emulsion layer, a green sensitive silver halide emulsion layer and a red sensitive silver halide emulsion layer on a support. In the method, silver halide grains which have a silver bromide containing phase of which the silver bromide content is from 10 to 60 mol % localized at the surface or within the grains, and in which from 95 to 99.5 mol % (average value) of the grains as a whole in the emulsion layer consists of silver chloride, the remainder consisting of substantially silver iodide free silver bromide, are included in at least one of the green sensitive and red sensitive silver halide emulsion layers. The material is subjected to a scanning exposure with blue light, green light and red light.

Abstract: The essential feature of the color image recording apparatus of the present invention is that it uses a laser light source capable of simultaneous emission of laser beams associated with exposure to R, G and B light. The apparatus also uses a light deflector and a device for selectively reflecting or transmitting said laser beams, for example, a rotating polygonal mirror in which at least one of the reflecting faces has a different spectral characteristic of reflection than other faces or a light deflector and at least one color filter that operates in synchronism with the light deflector.In the present invention, a laser beam having a wavelength associated with exposure to light either one or R, G and B colors is separated from the light beams emitted from the laser light source, and the recording material is exposed to successive beams of different colors, one for each scanning line, to insure exposure for a full-color image by three scanning lines.

Abstract: An optical wavelength converter system includes a semiconductor laser for emitting a laser beam, the semiconductor laser having an external resonator such as a reflective grating, and an optical wavelength converter device disposed inwardly of the resonator and comprising a bulk single-crystal of organic nonlinear optical material. The bulk single-crystal is oriented to achieve angular phase matching between a laser beam emitted from the semiconductor laser and applied to the bulk single-crystal and a wavelength-converted wave.

Abstract: A laser-diode-pumped solid-state laser including a solid-state laser rod doped with a rare-earth material such as neodymium, a semiconductor laser for emitting a laser beam to pump said solid-state laser rod to oscillate a beam, and a resonator including a bulk single crystal of organic nonlinear optical material for converting the wavelength of the beam which is oscillated by said solid-state laser rod. The organic nonlinear optical material is preferably PRA, MNA, NPP, NPAN, MAP, m-NA, or the like. The semiconductor laser may comprise a single-transverse-mode, or a single-longitudinal-mode semiconductor laser.

Abstract: A fundamental wave is caused to enter a Cerenkov-radiation type optical wavelength converter device which is formed of a single-crystal organic nonlinear optical material of an orthorhombic system of mm2 point group disposed in a cladding as a waveguide and a wavelength-converted wave such as a second harmonic whose wavelength within the range of 430 to 500 nm is extracted. The wavelength of the fundamental wave is selected so that the wavelength of the wavelength-converted wave becomes longer than the absorption edge of the organic nonlinear optical material by at least 30 nm. The fundamental wave is linearly polarized in the direction of the x-optic-axis or the y-optic-axis of the crystal of the organic nonlinear optical material and then caused to enter the optical wavelength converter device, and a wavelength-converted wave which is linearly polarized in the z-optic-axis of the crystal is extracted.

Abstract: An optical wavelength converter device is in the form of a three-dimensional optical waveguide and comprises a cladding and a waveguide element embedded in the cladding and having a refractive index higher than that of the cladding. Each of the cladding and the waveguide element is made of a III - V group, mixed-crystal compound semiconductor material or a II - VI group, mixed-crystal compound semiconductor material. The cladding includes homogeneous portions covering all surfaces of the waveguide element which fully reflect the fundamental wave being guided in the waveguide element.

Abstract: An optical wavelength converter module includes an optical wavelength converter device having a cladding and a waveguide which is disposed in the cladding and has a higher refractive index than the cladding, at least one of the cladding and the waveguide being made of a nonlinear optical material, whereby the wavelength of a fundamental which is propagating in the waveguide is converted. The optical wavelength converter module also includes a semiconductor laser for emitting a laser beam which is introduced as the fundamental into the waveguide. The semiconductor laser is driven with a pulsed drive current.

Abstract: An optical wavelength converter device of the optical fiber type comprises a core made of a nonlinear optical material and cladding of an amorphous material and surrounding the core, the cladding having a refractive index lower than the refractive index of the core. Another optical wavelength converter device comprises a two- or three-dimensional optical wavelength converter device produced by growing a nonlinear optical material crystal as an optical waveguide on or in an amorphous substrate having a refractive index lower than the refractive index of the nonlinear optical material crystal. Phase matching is achieved between a radiation mode of a wavelength-converted wave in the cladding or the substrate and a nonlinear polarized wave generated by a waveguide mode of first and second fundamental waves in the core or the optical waveguide.

Abstract: A printer has a feeding path for guiding a printing paper from and toward an opening of the printer. A cross-sectional shape of the feeding path is minimized to be sufficient to pass the printing paper through the feeding path. At least one resonator is arranged in the feeding path. The resonator has a case defining a resonant chamber and holes formed on the case along with the feeding path. The resonant chamber communicates with the feeding path through the holes. Noises such as impact sound generated by a printing head of the printer are silenced by the resonator at frequencies around a resonance fequency of the resonator, and further silenced by the area reduced portion of the feeding path.