Riken Corporation

Japan Science and Technology Agency

Furukawa Co., Ltd.

Hiromasa Ito

Hiroaki Minamide

Masato Yoshida

Kouji Nawata

Akihide Hamano

Seigo Ohno

Koichiro Nakamura

Kodo Kawase

Tomofumi Ikari

Koda Kawase

Feng Qi

Jun-ichi Shikata

Ruixiang Guo

Toshiyuki Miyamoto

Takashi Notake

Shin'ichiro Hayashi

Kazuhiro Imai

Shuzhen Fan

Mikiko Saito

An optical response measuring device is provided with a light source, first and second wavelength conversion elements and a light intensity sensor array. The light source generates a pair of light beams including light beams of first and second wavelengths, and the first wavelength conversion element generates measurement light. The measurement light is irradiated on an object for measurement and a detection light having first phase and second phase is obtained in response to this irradiation. A reference light that carries the phase of the pair of the pair light beams and the detection light both pass through a second wavelength conversion element to obtain a modulated reference light have first and second intensities. The first and second local intensities are then measured by the light intensity sensor array.

Optical response measuring device and optical response measuring method

The present invention includes a slanted periodically poled deviceincluding a light input surfaceand a light output surfaceparallel to each other and a terahertz wave input surfaceorthogonal to the light input surfaceand the light output surface, a pump beam sourcewhich emits pump beamperpendicularly to the light input surface, and a photodetectorwhich detects an up-conversion signal beam A converted from a terahertz waveemitted perpendicularly from the light output surface. The slanted periodically poled deviceis configured to generate the up-conversion signal beam A in the same direction as and in parallel with the pump beamby quasi phase matching between the terahertz waveperpendicularly incident from the terahertz wave input surfaceand the pump beam

Terahertz wave detection device and method

An object of the present invention is to produce a non-conventional high-quality BNA single crystal. Another object of the present invention is to provide a process for producing the above-described high-quality BNA single crystal. Specifically, the present invention provides a BNA crystal characterized by having a half-value width of diffraction peak X-ray intensity of 100 seconds or less in a rocking curve measurement by X-ray diffraction method.

BNA crystal

A mobility measuring apparatus includes a storage unit that respectively stores a relationship between the mobility &#x3bc; of carriers in a semiconductor and a decay constant &#x3b3; of the carriers and a relationship between a reflectivity R of the semiconductor to a terahertz light and the decay constant &#x3b3; of the carriers, a light radiating unit that radiates a terahertz light to the semiconductor as a sample, a detecting unit that detects a reflected light of the sample to the radiated terahertz light, a reflectivity calculating unit that calculates the reflectivity Rof the sample by determining a ratio of an intensity of the reflected light relative to an intensity of the radiated terahertz light, an obtaining unit that obtains the decay constant &#x3b3;of the sample corresponding to the reflectivity Rof the sample by making reference to the stored relationship between the reflectivity R and the decay constant &#x3b3; of the carriers, and a mobility calculating unit that calculates the mobility &#x3bc;of the sample from the stored relationship between the mobility &#x3bc; and the decay constant &#x3b3; on the basis of the obtained decay constant &#x3b3;.

Mobility measuring apparatus, method therefor, and resistivity measuring apparatus and method therefor

To provide a monochromatic wavelength variable terahertz wave generation/detection system that has high detection sensitivity at room temperature and that can quickly operate at the same time, excitation light of monochromatic wavelength generated from one excitation light source is inputted to a wavelength variable terahertz wave source and a nonlinear light conversion terahertz wave detector through an excitation light phase control optical system shown below. The excitation light phase control optical system includes, on a light path of the excitation light, an optical element capable of simultaneously changing an incidence angle of the excitation light to a generation point of a terahertz wave in the wavelength variable terahertz wave source and an incidence angle of the excitation light to an incidence point of the terahertz wave in the nonlinear light conversion terahertz wave detector to set both the generation point and the incidence point at the same time on the focal points in a confocal optical system.

Monochromatic wavelength variable terahertz wave generation/detection system and method

A nondestructive carrier concentration measuring device () includes: a storage unit () that stores a correlation between the reflectance of an inorganic compound semiconductor against terahertz light and a carrier concentration; a light radiation unit () that irradiates the terahertz light () to the inorganic compound semiconductor as a sample; a detection unit () that detects reflected light () of the inorganic compound semiconductor against the irradiated terahertz light (); a reflectance calculation unit () that compares the irradiated terahertz light () with the reflected light () and calculates an actual measurement value of the reflectance of the inorganic compound semiconductor; and a read unit () that refers to the stored correlation and reads the carrier concentration of the sample corresponding to the actual measurement value of the reflectance.

Carrier concentration measuring device and carrier concentration measuring method

A method and an apparatus for generating a terahertz wave, wherein one end faceof a non-linear optical crystalis positioned approximately orthogonally to a direction of generation of a terahertz wave, pump lightand idler lightare totally reflected at an approximately same pointon the end face, and the generated terahertz waveis emitted roughly vertically to the end face.

Method and apparatus for generating terahertz wave

There are disclosed a nonlinear optical crystalwhich can generate a THz wave by a parametric effect; a pump light incidence apparatusfor allowing a pump lightto be incident upon the nonlinear optical crystal; and a seed light injection apparatusfor injecting a seed lighthaving a variable frequency in a generation direction of an idler lightgenerated by the pump light. The seed light injection apparatuscomprises angle dispersion compensation meansset so that an incidence angle &#x3b8;of the seed light upon the nonlinear optical crystalsubstantially equals to a desired phase matching condition regardless of a wavelength.

Apparatus for generating tera-Hertz wave and tuning method

A group velocity dispersion measuring device capable of measuring group velocity dispersion (GVD) with a simple configuration and in a short time, comprising an FSF laser (FSFL) () for generating frequency chirp light, an optical amplifier (AMP) () for amplifying the frequency chirp light, an optical coupler (), a circulator () for branch-controlling optical signals, a photodetector () for receiving a ray of light before and after its propagation through an optical fiber () to be measured, and an RF spectrum analyzer (RFSA) () for observing an optical spectrum waveform. Beat signals generated between chirp lights before and after the propagation, through the optical fiber () to be measured, of frequency chirp light emitted from the FSF laser () are alternately observed to calculate a GVD value from frequency differences between these beat signals.

Group velocity dispersion measuring device and group velocity dispersion measuring method

An apparatus and method for measuring polarization mode dispersion (PMD) using a polarization mode dispersion measuring device, comprising an FSF laser generating frequency chirped light, an optical amplifier amplifying the frequency chirped light, an offset circuit, a &#x3bb;/2 plate, a beam splitter, an analyzer retrieving polarization components measured from each light wave after propagating through the fast axis and the delay axis of the optical fiber under test, a lens, a photodetector detecting a light wave passed through the lens, and an RF spectrum analyzer observing a spectrum waveform of the light wave. The frequency chirped light, after propagating through the optical fiber under test and passing through the analyzer, is detected and the variation in beat frequency is measured to determine a PMD value.

Polarization mode dispersion measuring device and polarization mode dispersion measuring method

A THz-wave generator according to the present invention includes a nonlinear optical crystal capable of parametric generation, a first laser device for injecting a single-frequency first laser beam as a pump wave into the nonlinear optical crystal, and a second laser device for injecting a different single-frequency second laser beam to thereby injection-seed a second laser beam in a direction in which an idler wave is generated by the pump wave. By this configuration, it is possible, in generation of a THz-wave by use of the parametric effect in the nonlinear optical crystal under a non-collinear phase matching condition, to greatly increase a power of the THz-wave, to narrow its spectrum width, to make variable the wavelength of a generated THz-wave, and to hold its generation direction almost constant.

Growing community of inventors

Saitama, Japan

Hiromasa Ito