National Institute for Materials Science

Sumitomo Osaka Cement Co., Ltd.

Nikon Corporation

Nidek Co., Ltd.

National Institute of Information and Communications Technology, Incorporated

Sunao Kurimura

Kenji Kitamura

Junichiro Ichikawa

Futoshi Yamamoto

Satoshi Oikawa

Masaki Harada

Shunji Takekawa

Masaru Nakamura

Kenichi Muramatsu

Tsuyoshi Yamada

Masahiro Tsuchiya

Tetsuya Kawanishi

Masayuki Izutsu

Katsutoshi Kondou

Kaoru Higuma

Kazuya Terabe

Shingo Mori

Masayuki Ichioka

Shunichi Hishida

Tamaki Shimura

Masaki c/o Nikon Corporation Harada

According to one embodiment, an optical element is provided with a paraelectric crystal, first and second pressers between which the paraelectric crystal is sandwiched, and fasteners. The paraelectric crystal has a periodic structure in which polarities are periodically inverted along a polarity period direction. The fasteners fix the first and second pressers to each other so that a predetermined pressure is applied in a direction intersecting with the polarity period direction, to the paraelectric crystal through the first and second pressers.

Optical element, light source device, and optical element production method

A method for forming a ferroelectric spontaneous polarization reversal in a desired region of a ferroelectric substrate includes the steps of forming, for the desired region of the surface of the ferroelectric substrate, an electrode pattern or a mask pattern composed of aggregates of micropatterns, and then applying a given voltage into the desired region. The configuration of the micropatterns can be a stripe-shaped pattern, an ellipse-shaped pattern, a hexagon-shaped pattern, a network pattern, or a double cross shaped pattern. The method can further include the steps of generating many nucleuses by using the electrode pattern or the mask pattern composed of the aggregates of micropatterns, forming another electrode pattern or another mask pattern corresponding to the desired region, and then applying a given voltage into the desired region to generate a ferroelectric spontaneous polarization reversal around the nucleuses.

Method for forming polarization reversal

A method for forming a ferroelectric spontaneous polarization reversal, including the steps of forming a concave portion on a top face of a ferroelectric substrate or a bottom face of a ferroelectric substrate, and applying an electric field into the substrate, wherein a ferroelectric spontaneous polarization reversal is formed at least in one portion of a region of the substrate with the concave portion, and wherein the shape of the concave portion is configured such that the width of the concave portion gets narrower gradually toward the inside of the substrate. The method may further include the steps of, after the reversal, making into almost a flat-plane the top or bottom face having the concave portion, and then, forming a new concave portion in another region and applying an electric field to form another reversal in one portion of the region of the substrate having the new concave portion.

A wavelength conversion element is provided as one including a monocrystalline nonlinear optical crystal. The nonlinear optical crystal has: a plurality of first regions having a polarity direction along a predetermined direction; a plurality of second regions having a polarity direction opposite to the predetermined direction; an entrance face into which a fundamental incident wave having a wavelength &#x3bb; and a frequency &#x3c9; is incident in a direction substantially perpendicular to the predetermined direction; and an exit face from which a second harmonic with a frequency 2&#x3c9; generated in the crystal emerges. The plurality of first and second regions are formed as alternately arranged in a period substantially equal to d expressed by a predetermined expression, between the entrance face and the exit face.

Wavelength conversion element, wavelength conversion method, phase matching method, and light source device

A method for forming a ferroelectric spontaneous polarization reversal includes the steps of forming a convexo-concave structure on a top face of a ferroelectric substrate firstly, and then forming a ferroelectric spontaneous polarization region on the substrate including one portion of a convex portion, with a concave portion being formed on the bottom face of the substrate within a region where a ferroelectric spontaneous polarization reversal is to be formed and the convex portion is formed, and then applying an electric field into the substrate. The depth of the concave portion on the bottom face of the substrate may be greater than the height of the convex portion on the top face of the substrate. The width of the concave portion on the bottom face of the substrate may be wider than width of said convex portion on the top face of the substrate.

A method for forming a ferroelectric spontaneous polarization reversal in a desired region of a ferroelectric substrate, wherein thickness of the ferroelectric substrate in the desired region A of the ferroelectric substrate is thinner than in a region B outside the desired region of the substrate, comprising the step of applying a given voltage into the ferroelectric substrate by a liquid electrode method to thereby form a ferroelectric spontaneous polarization reversal in the desired region of the ferroelectric substrate.

Method for forming ferroelectric spontaneous polarization reversal

An optical device and a method of manufacturing the optical device, with the method including the steps of forming a dopant layer on a stoichiometric lithium niobate single crystal substrate with Li to Nb mole composition ratio of 49.5% to 50.5%, and diffusing a dopant in the dopant layer into at least a portion of the stoichiometric lithium niobate single crystal substrate. The stoichiometric lithium niobate single crystal substrate includes 0.5 to 5 mol % of Mg. In the diffusing step, a heat treatment is performed at a diffusion temperature of 1000&#xb0; C. to 1200&#xb0; C. for a diffusion time of 3 hours to 24 hours in a dry atmosphere of at least one of O, N, Ar and He gas having a dew-point temperature of &#x2212;35&#xb0; C. or less.

Optical device and method of manufacturing the same

A manufacturing method for quasi phase matching (QPM) wavelength converter elements using crystal quartz as a base material in which twins are periodically induced, comprises a step of periodically inducing the twins by applying a stress onto a crystal quartz substrate as the base material so that an angle &#x3b8; of a direction in which the stress is applied relative to a Z axis of the crystal quartz is 60&#xb0;&#x3c;&#x3b8;&#x3c;90&#xb0;.

Manufacturing method for QPM wavelength converter elements, QPM wavelength converter element, and medical laser apparatus using it

A nested modulator is provided where the circuit arrangement of modifying electrodes including signal electrodes is simplified, and at the same time, the drive voltage can be lowered. A nested modulator, including: a substratemade of a material having electro-optic effects; an optical waveguide formed on the substrate; and a modulating electrode for modulating light waves which are guided through the optical waveguide, wherein the optical waveguide has a main Mach-Zehnder waveguideand sub-Mach-Zehnder waveguidesandprovided on two branching waveguides of the main Mach-Zehnder waveguide, and the modulating electrode is provided in a sub-branching waveguide of the sub-Mach-Zehnder waveguides, is characterized in that a polarization reversal regionoris formed in a portion of a sub-branching waveguide of each of the sub-Mach-Zehnder waveguides, the modulating electrode is formed of signal electrodes including introduced signal electrodesor, branching single electrodesorand lead signal electrodesoras well as ground electrodes for each of sub-Mach-Zehnder waveguides, and the branching signal electrodes which branch from the introduced signal electrode are placed so as to work on two sub-branching waveguides for each of the sub-Mach-Zehnder waveguides.

Nested modulator

A problem to be solved is to provide a method of forming domain inverted regions of short period in a ferroelectric single crystal in a controllable time period of application of voltage and an optical wavelength conversion element using the same. A solving means of it solves the problem by forming (i) a control layer having a larger defect density Dthan the defect density Dof a ferroelectric single crystal (D&#x3c;D) or forming (ii) a control layer having a lower degree of order of lattice points than the degree of order of lattice points of the ferroelectric single crystal on a face perpendicular to the direction of polarization of the ferroelectric single crystal in the ferroelectric single crystal.

Method of inverting polarization by controlling defect density or degree of order of lattice points

The upper blockcontacts the bearing block, and the bearing blockis coupled to the upper plate. The upper blockhas a protruding parton the upper surface that is worked into a convex surface with a radius of R1, and the bearing blockhas a recessed partin the undersurface that is worked into a concave surface with a radius of R(R&#x3e;R). As a result of such a construction being used, the pressing surface of the upper pressing platealways conforms to the surface of the quartz crystal substrateduring pressing, so that a uniform load is applied to the quartz crystal substrate. As a result, the surface of the quartz crystal can be uniformly pressed in the hot pressing method.

Crystal base plate and pressing device

A wavelength conversion element having multi-gratings free from damage propagation and a light generating apparatus using it, and a wavelength conversion element having multi-gratings to make a thermal distribution centrosymmetric, and being free from damage propagation, are provided. The wavelength conversion element is realized by comprising a holder and plural prismatic ferroelectric single crystals disposed in the holder, wherein plural prismatic ferroelectric single crystals have at least five planes; the aspect ratios of planes perpendicular to respective longitudinal directions of the plural prismatic ferroelectric single crystals are virtually unity; and each of the plural prismatic ferroelectric single crystals has a domain inversion structure with a predetermined period in the direction perpendicular to the polarization direction thereof, and is arranged in a way that said direction perpendicular to the polarization direction is the same as those of the other crystals.

Wavelength conversion element having multi-gratings and light generating apparatus using said element, and wavelength conversion element having cylindrical ferroelectric single crystals and light generating apparatus using said element

Rectangular protruding partsare formed on the surface of one side of a quartz crystal substrate; these protruding partsare formed as aggregates of rectangular protruding partsof an even finer pattern. Recessed partswhich are lower than the surfaces of the protruding partsare formed between the protruding parts; however, the width of these recessed partsis narrow, so that when the protruding partsare viewed on the macroscopic scale, numerous protruding partsare aggregated, and appear to form single protruding parts. Such a quartz crystal substrateis clamped between heater blocks from above and below, and the temperature of the quartz crystal substrate is elevated. At the point in time at which this temperature reaches a desired temperature, the substrateis pressed by means of a press. Consequently, stress acts only on the portions corresponding to the protruding parts, so that the crystal axis components are inverted only in these portions. These portions with inverted crystal axes grow into the interior portion of the crystal, and are propagated into the interior portion of the crystal, so that the portions corresponding to the protruding partsare connected, thus forming crystal axis inversion regions. As a result, crystal axis inversion regions with a desired shape can easily be formed.

Growing community of inventors

Tsukuba, Japan

Sunao Kurimura