Abstract:
A terahertz wave transceiver configured to generate and detect terahertz waves based on time-domain spectroscopy includes a photoconductive device having a photoconductive film, a first electrode, and a second electrode. An excitation light illumination region is formed between the first and second electrodes. A bias applying unit applies a bias between the first electrode and the second electrode to generate the terahertz wave in the excitation light illumination region. A current detection unit detects a terahertz-wave current that is a component of a current generated in the excitation light illumination region and that is generated by an electric field of a received terahertz wave arriving from the outside. A current drawing unit draws a current originating from the bias applied by the bias applying unit. An adjustment unit determines the amount of the current drawn, based on the amount of the bias applied by the bias applying unit.
Abstract:
An optical filter device includes an interference filter and a housing. The interference filter includes a fixed substrate, a movable substrate joined to the fixed substrate, a fixed reflective film provided on the fixed substrate, and a movable reflective film provided on the movable substrate and opposed to the fixed reflective film across an inter-reflective film gap. The housing includes a base substrate on which the interference filter is arranged. A fixing member is arranged between the movable substrate and the base substrate. The movable substrate is fixed to the base substrate by the fixing member in one place excluding a region where the movable reflective film is provided.
Abstract:
A handheld or portable detection system with a high degree of specificity and accuracy, capable of use at small and substantial standoff distances (e.g., greater than 12 inches) is utilized to identify specific substances and mixtures thereof in order to provide information to officials for identification purposes and assists in determinations related to the legality, hazardous nature and/or disposition decision of such substance(s). The system uses a synchronous detector and visible light filter to enhance detection capabilities.
Abstract:
An optical pulse generating apparatus that supplies pump light and probe light includes a light source and a modulation unit configured to modulate light emitted from the light source, thereby dividing the light into the pump light and the probe light. The modulation unit is configured such that a frequency for modulating the light is variable. The modulation unit changes a difference between a moment of the pump light incident on an object and a moment of the probe light incident on the object by changing the frequency.
Abstract:
Systems and methods for analysing a time-domain signal are described. The method comprising: in a mixer (150), mixing the time-decay signal (115) with a local oscillator signal (122) generated by a local oscillator (120), resulting in a mixed signal from which a Fourier transformed time-decay signal is generated comprising a fundamental transformed time decay signal at the fundamental frequency of the local oscillator signal (122) and a plurality of transformed time-decay signals at a plurality of frequencies; and determining the magnitude of each of the transformed time-decay signals at the fundamental frequency and at a frequency other than the fundamental frequency.
Abstract:
An optical device for determining the presence and/or concentration of analytes in a sample is presented. The optical device comprises a detector and a detection unit comprising optical path components. The detection unit has wavelength-dependent responsivity. The optical device further comprises a light source for emitting light of different respective usable wavelength ranges. The light is guidable through the optical path to the detector to generate baseline signals and response signals relative to the baseline signal indicative of the presence and/or concentration of analytes in the optical path. The intensity of the light reaching the detector is adjusted inverse to the wavelength-dependent responsivity with respect to at least two respective usable wavelength ranges so that a reduction of the ratio between the maximum baseline signal at one of the selected usable wavelength ranges and the minimum baseline signal at another of the selected usable wavelength ranges is obtained.
Abstract:
A method and apparatus for automated spectral calibration of a spectroscopy device. A method for simultaneous calibration and spectral imaging of a sample by: simultaneously illuminating the sample and a calibrant with a plurality of illuminating photons; receiving, at the spectrometer, a first plurality of photons collected from the sample and a second plurality of photons collected from the calibrant; forming a calibrant spectrum from the first plurality of collected photons and a sample spectrum from the second plurality of collected photons; comparing the calibrant spectrum with a reference spectrum of the calibrant to determine a wavelength-shift in the calibrant spectrum; applying the wavelength-shift to the sample spectrum to obtain a calibrated sample spectrum.
Abstract:
A spectrometer includes a light source section that includes a plurality of LEDs having different emission wavelengths, a variable wavelength interference filter that selectively extracts light of a predetermined wavelength, a detector that detects the amount of light, and a control circuit section. The control circuit section includes a mode switching section that switches a calibration mode and a measurement mode, an outside light analysis section that analyzes characteristics of outside light in the calibration mode, a reference light setting section that set the amount of light emitted from each of the LEDs on the basis of the characteristics of the outside light, and a light source driving section that drives each of the LEDs on the basis of the amount of light emitted which is set in the measurement mode.
Abstract:
This application describes designs, implementations, and techniques for controlling propagation mode or modes of light in a common optical path, which may include one or more waveguides, to sense a sample.
Abstract:
A method for measuring a wave surface of an optical component formed of a stack of at least two layers of different refraction indices from reflection or transmission measurements of points located on a face of the said optical component.