Canon Kabushiki Kaisha

Kousuke Kajiki

Toshihiko Ouchi

Ryota Sekiguchi

Takeaki Itsuji

Yasushi Koyama

A terahertz wave generating element includes a nonlinear optical crystal generating terahertz waves by propagating light, and a coupling member propagating the generated terahertz waves. The coupling member includes a reflecting face reflecting at least part of the generated terahertz waves. The reflecting face is convex in a propagation direction of the generated terahertz waves. An angle at the coupling member side between the reflecting face and the propagation direction of the light is greater than 90 degrees&#x2212;cos(n/n) but smaller than 90 degrees at a plane including the light propagation direction. nrepresents a group refractive index of the nonlinear optical crystal at a wavelength of the light, nthe refractive index of the coupling member at a wavelength of the generated terahertz waves. A curvature radius of the reflecting face, in a reflection region reflecting the radius terahertz waves, is smaller the farther downstream in the light propagation direction.

Terahertz wave generating element and terahertz wave detecting element

An electromagnetic wave generating device is provided which includes an optical waveguide including a plurality of waveguide segments such that the main lobe of a combined electromagnetic wave has a substantially single large directivity. The electromagnetic wave generating device includes the optical waveguide including a plurality of waveguide segments each of which is sandwiched between dielectrics and includes a nonlinear optical crystal. The waveguide segments are arranged such that an angle formed by the directions of propagation of light in the two adjacent waveguide segments substantially corresponds to 2&#x3b8;. When ndenotes the refractive index of the nonlinear optical crystal for light and &#x2208;denotes the effective relative permittivity of an assembly of the dielectrics and the waveguide segments for an electromagnetic wave, &#x3b8;is defined as &#x3b8;=cos(n/&#x3b8;&#x221a;&#x2208;).

Electromagnetic wave generating device, electromagnetic wave detecting device, and time-domain spectroscopy apparatus

To provide an electromagnetic pulse transmitting apparatus and a tomography apparatus capable of shortening an electromagnetic pulse. The apparatus performs processing such that two electromagnetic pulse portions emitted to an object have an electric field intensity of mutually opposite polarity and the time difference between pulse peaks of the two electromagnetic pulse portions is a time difference within a time of a pulse width.

Tomography apparatus and electromagnetic pulse transmitting apparatus

Provided is a photoconductive element which solves a problem inherent in an element for generating/detecting a terahertz wave by photoexcitation that terahertz wave generation efficiency is limited by distortions and defects of a low temperature grown semiconductor. The photoconductive element includes: a semiconductor substrate; a semiconductor low temperature growth layer; and a semiconductor layer, which is positioned between the semiconductor low temperature growth layer and the semiconductor substrate and is thinner than the semiconductor low temperature growth layer, in which the semiconductor low temperature growth layer includes a semiconductor which lattice-matches with the semiconductor layer and does not lattice-match with the semiconductor substrate.

Photoconductive element

A photoconductive element for performing at least one of generation and detection of terahertz radiation includes a photoconductive layer formed of a semiconductor material and configured to generate photoexcited carriers by being irradiated with excitation light, and a plurality of electrodes provided on the photoconductive layer. The material of the photoconductive layer is a material that makes a depletion layer produced in the photoconductive layer have a thickness smaller than an optical absorption length of the photoconductive layer for a wavelength of the excitation light. A film thickness of the photoconductive layer is adjusted so that the depletion layer is formed over an entirety in a direction of the film thickness within at least a portion of the photoconductive layer between the plurality of electrodes.

A terahertz wave generation element includes a plurality of waveguides including an electro-optic crystal, and an optical coupling member for extracting a terahertz wave to the outside. The terahertz wave is generated when light propagates through the waveguides. The waveguides are arranged to be rotationally symmetric with respect to a predetermined axis. The optical coupling member is arranged so that wave fronts of the terahertz waves generated from the waveguides are matched together.

Terahertz wave generation element, terahertz wave detection element, and terahertz time domain spectral device

An information acquiring apparatus includes a light source portion for generating pulse-shaped pump light, and first and second probe light in synchronization with each other. A generating portion generates terahertz pulses when irradiated with the pump light. A detecting portion detects pulses of terahertz radiation from the object. A first delay portion adjusts an optical path difference between optical paths of the pump light and the first probe light reaching the detecting portion, so that the detecting portion detects a field intensity of a fixed point on the time domain waveform of the terahertz pulse from the object, following the fixed point. A second delay portion adjusts an optical path difference between the optical path of the pump light and the second probe light reaching the detecting portion by a sum of an additional optical path adjustment amount and the optical path difference, so that the detecting portion obtains the time domain waveform. A correction processing portion compensates for influence of a change in condition of the object on the time domain waveform, using the field intensity of the fixed point, or the adjustment amount adjusted by the first delay portion.

Compensation in terahertz time domain spectroscopy having two delays

An optical frequency converter includes a waveguide including a core made of a nonlinear optical medium having a refractive index nin a wavelength region of light, and cladding disposed so as to cover the core and made of a material whose refractive index nin the wavelength region of light is lower than the refractive index n, and a coupling section made of a material whose refractive index nin a wavelength region of a terahertz wave is higher than the refractive index nand disposed in contact with the cladding. The coupling section is configured to couple the waveguide with a space in the wavelength region of the terahertz wave. The coupling section covers the cladding.

Optical frequency converter

A photoconductive device includes: a photoconductive layer configured to generate carriers upon irradiation with excitation light, a first electrode arranged on the photoconductive layer, a second electrode arranged on the photoconductive layer with a gap between the first and second electrodes, and a third electrode arranged in a region over which an electric field caused by voltages applied to the first and second electrodes or an electric field caused by irradiation with a terahertz wave extends. A depletion layer of the photoconductive layer is controllable by a voltage applied to the third electrode.

Photoconductive device, and terahertz wave generation and detection apparatuses each using the photoconductive device

An analysis apparatus for analyzing a specimen comprises a spectral separator for dispersing spatially an electromagnetic wave introduced from the specimen into spectral components, a sensing element array containing plural sensing elements for sensing the spectral components of the electromagnetic wave dispersed spatially by the spectral separator, and a spectrum calculator for calculating the spectrum from the signal sensed by the sensing elements; the sensing element array having sensitivities different to each of the spectral components of the electromagnetic wave dispersed spatially by the spectral separator, and the spectral separator and the sensing element array being placed so as to receive the spectral components by each of the sensing elements at different incident angles.

Analysis apparatus for analyzing a specimen by obtaining electromagnetic spectrum information

An object information acquisition apparatus for acquiring information on the inside of an object includes an electromagnetic wave generation unit capable of outputting a terahertz wave and of changing the output intensity, an irradiation unit that irradiates an electromagnetic wave onto an object, a scanning unit and a detection unit that detects the electromagnetic wave irradiated onto the object. The scanning unit changes the relative positions of the irradiated electromagnetic wave and the object. The detection unit detects the electromagnetic wave transmitted through or reflected by the object as a result of interaction of the object and the electromagnetic wave.

Growing community of inventors

Tokyo, Japan

Kousuke Kajiki