Hamamatsu-photonics K.k.

Takashi Yasuda

Yoichi Kawada

Hironori Takahashi

Atsushi Nakanishi

Kouichiro Akiyama

Shinichiro Aoshima

Haruyasu Ito

Kazuki Horita

Masatoshi Fujimoto

Toru Matsumoto

Takayoshi Kuga

Kazutaka Tomari

A wave plate comprising: a prism member having an entrance surface for receiving a terahertz wave T, and an exit surface for emitting the terahertz wave T received by the entrance surface; wherein the prism member is constituted by a plurality of waveguide regions having: a partial entrance surface for receiving a part of the terahertz wave T, a plurality of total reflection surfaces for totally reflecting the terahertz wave T from the partial entrance surface, and a partial exit surface for emitting the terahertz wave T totally reflected from the total reflection surfaces; and each of the partial entrance surfaces combine to constitute the entrance surface of the prism member, and each of the partial exit surfaces combine to constitute the exit surface of the prism member, by stacking waveguide regions.

Wave plate and divided prism member

A measurement auxiliary member is placed on an arrangement surface of a prism. A measurement object is placed on an upper surface of the measurement auxiliary member. The measurement auxiliary member totally reflects the terahertz wave input from a lower surface by the upper surface and outputs the totally-reflected terahertz wave from the lower surface. A main pulse of a terahertz wave totally reflected by the upper surface of the measurement auxiliary member without multiply-reflected inside any optical element on an optical path of the terahertz wave, and a noise pulse of a terahertz wave multiply-reflected inside any optical element on the optical path and reflected on an interface between the prism and the measurement auxiliary member, are temporally separated from each other when detecting a correlation by a terahertz wave detection element.

Terahertz wave spectroscopic measurement apparatus and terahertz wave spectroscopic measurement method

Disclosed is a non-linear optical crystal containing pyridinium represented by the following Formula (1), 4-substituted phenylsulfonate represented by the following Formula (2a), and 2,4,6-substituted phenylsulfonate represented by the following Formula (2b). 

Non-linear optical crystal and method for manufacturing same, and terahertz-wave generator and terahertz-wave measuring apparatus

In a terahertz-wave spectrometer, a spectroscopic prism is provided with a prism part slidable with respect to a main part thereof. Along the sliding direction, an arrangement surface in an upper face of the prism part is provided with a plurality of arrangement regions K to be arranged with objects to be measured. Therefore, after completing the measurement of optical constants for one object, the prism part is slid, so as to shift the next object onto an optical path of a terahertz wave T, whereby a plurality of objects can be measured smoothly without cleaning the arrangement surface.

Terahertz-wave spectrometer

In this electric field vector detection method, an electro-optic crystal, where a (111) surface of an optical isotropic medium is cut out, is used as a terahertz wave detection element. The method includes: causing polarization of probe light of ultrashort pulsed light to be circular polarization; allowing the probe light having circular polarization to enter the terahertz wave detection element and probing the terahertz wave; modulating the probe light, having probed the terahertz wave, by a rotating analyzer and detecting the modulated probe light by a photodetector; performing lock-in detection of a detection signal from the photodetector by a lock-in detector using a frequency based on a rotational frequency of the rotating analyzer as a reference signal; and detecting an electric field vector of the terahertz wave based on a detection signal from the lock-in detector.

Electric field vector detection method and electric field vector detection device

A prism member having an entrance surface for arranging a terahertz-wave generator for generating a terahertz wave in response to pump light incident thereon, an arrangement part for arranging an object to be measured, an exit surface for arranging a terahertz-wave detector for detecting a correlation between the terahertz wave transmitted through the object in the arrangement part and probe light, a first optical surface for collimating or condensing the terahertz wave incident thereon from the entrance surface toward the arrangement part, and a second optical surface for condensing the terahertz wave transmitted through the arrangement part toward the exit surface, the arrangement part forms a depression adapted to be filled with a liquid incapable of dissolving the object therein.

Prism member, terahertz-wave spectroscopic measurement device, and terahertz-wave spectroscopic measurement method

A terahertz wave temporal waveform acquisition apparatus includes a light source, a branch part, a terahertz wave generation element, a terahertz wave detection element, a delay providing medium, a temperature adjustment unit, and an analysis unit. The delay providing medium is disposed on an optical path of a terahertz wave from the terahertz wave generation element to the terahertz wave detection element, is formed of a material of which a refractive index for the terahertz wave depends on the temperature, and provides a delay according to the temperature to the terahertz wave.

Terahertz wave temporal waveform acquistion apparatus

A method for designing an optical component for shaping laser light according to one embodiment of this invention measures the intensity distribution of an incident laser light, obtains the shapes in the short and long axial directions of a pair of aspheric lenses for each of the short and long axial directions of the incident laser light from the measured intensity distribution of the incident laser light and a desired intensity distribution, performs approximation of a high-order polynomial of the shapes in the short and long axial directions of the pair of aspheric lenses, corrects the high-order polynomials for the short or long axial directions using a correction factor, and obtains the shapes of the pair of aspheric lenses on the basis of the corrected high-order polynomials.

Method for designing laser-light-shaping optical component, method for producing laser-light-shaping optical component, and laser-light-shaping optical system

By mating a main part with a first prism part or second prism part, a terahertz-wave spectrometer can easily switch between optical paths of a terahertz wave T propagating within a spectroscopic prism. When the main part mates with the first prism part, the terahertz wave T incident on an entrance surface passes through a depression, so as to be reflected by an arrangement part, whereby reflection spectrometry can be performed. When the main part mates with the second prism part, the terahertz wave T incident on the entrance surface is refracted by the depression, so as to pass through an object to be measured within a groove, whereby transmission spectrometry can be preformed.

Terahertz-wave spectrometer and prism member

Probe light pulses output from a light source are input to an optical effect unit after the beam diameter is changed by a beam diameter changing optical system, the pulse front is tilted by a pulse front tilting unit, and the beam diameter is adjusted by a beam diameter adjusting optical system. To the optical effect unit, probe light pulses output from the beam diameter adjusting optical system are input, and an electromagnetic wave being an object to be detected is also input. Optical characteristics of the optical effect unit change due to propagation of the electromagnetic wave, and probe light pulses affected by the change in optical characteristics are output from the optical effect unit. The probe light pulses output from the optical effect unit are detected by a photodetector.

Electromagnetic wave detection device

A laser light shaping and wavefront controlling optical systemin accordance with an embodiment of the present invention comprises an intensity conversion lensfor converting and shaping an intensity distribution of laser light incident thereon into a desirable intensity distribution; an optical modulation devicefor modulating the laser light emitted from the intensity conversion lensso as to control a wavefront thereof; a condenser optical systemfor converging the laser light issued from the optical modulation device; and an image-forming optical system, arranged between the optical modulation deviceand the condenser optical system, having an entrance-side imaging plane between a planewhere the laser light emitted from the intensity conversion lensattains the desirable intensity distribution and a modulation planeof the optical modulation deviceand an exit-side imaging plane on a pupil planeof the condenser optical system

Optical system for laser optical rectification and wave front control

A single terahertz wave time-waveform measuring deviceacquires information on an object to be measuredby using a terahertz wave, and includes a light source, a beam diameter adjuster, a separator, a terahertz wave generator, a light path length difference adjuster, a pulse front tilting unit, a polarizer, a wave synthesizer, an electro-optic crystal, an analyzer, and a photodetector. The terahertz wave generatorgenerates a pulse terahertz wave in response to an input of pump light and outputs the pulse terahertz wave. The pulse front tilting unitmakes pulse fronts of the terahertz wave and the probe light when being input into the electro-optic crystalnonparallel to each other by tilting the pulse front of the probe light.

Single terahertz wave time-waveform measuring device

A terahertz wave generating apparatusincludes an excitation light source, a transmission-type diffraction grating, a variable imaging optical system, and a nonlinear optical crystal. The transmission-type diffraction gratinginputs pulsed excitation light output from the excitation light source, and diffracts and outputs the pulsed excitation light. In the transmission-type diffraction grating, its orientation is variable with a straight central axis, that is parallel to the grooves and passing through an incident position of a principal ray of the pulsed excitation light. The variable imaging optical systemis configured to input the pulsed excitation light diffracted to be output by the transmission-type diffraction grating, to form an image of the pulsed excitation light by the transmission-type diffraction grating, and its imaging magnification is variable. The nonlinear optical crystalis disposed at a position at which the pulsed excitation light is formed as the image by the variable imaging optical system, and inputs the pulsed excitation light via the variable imaging optical system, and generates a terahertz wave T. Thereby, a terahertz wave generating apparatus, in which it is easy to adjust a phase matching condition, can be realized.

Terahertz wave generation device

A total reflection terahertz wave measuring apparatusincludes a light source, a branching part, a chopper, an optical path length difference adjusting part, a polarizer, a beam splitter, a terahertz wave generating element, a filter, an internal total reflection prism, a terahertz wave detecting element, a &#xbc; wavelength plate, a polarization split element, a photodetector, a photodetector, a differential amplifier, and a lock-in amplifier. The internal total reflection prismis a so-called aplanatic prism, and has an entrance surface, an exit surface, and a reflection surface. The terahertz wave generating elementand the filterare provided to be integrated with the entrance surfaceof the internal total reflection prism, and the terahertz wave detecting elementis provided to be integrated with the exit surfaceof the internal total reflection prism. The filterallows a terahertz wave to be transmitted therethrough and blocks pump light. Accordingly, a total reflection terahertz wave measuring apparatus, which can be downsized, can be realized.

Growing community of inventors

Hamamatsu, Japan

Takashi Yasuda