The invention relates to a terahertz full polarization state detection spectrometer, which comprises a terahertz wave generator, a polarizer, a polarization splitter, a horizontal terahertz detector and a vertical terahertz detector. The terahertz wave generator generates a terahertz wave and the polarizer optimizes the terahertz wave for purity. The sample to be detected modulates the terahertz wave after purity optimization to obtain the terahertz modulated wave. The terahertz modulated wave is decomposed by the polarization splitter into a horizontal terahertz wave and a vertical terahertz wave whose polarization states are perpendicular to each other. The two terahertz waves are detected by two corresponding terahertz detectors respectively. According to the detected result, the characteristic of the sample is analyzed. The terahertz full polarization state detection spectrometer can quickly and accurately detect all kinds of full polarization state terahertz waves and improve the detection accuracy and efficiency of the sample.

The present invention provides a far-infrared light source capable of reducing the shift in the location irradiated with far-infrared light even when the frequency of the far-infrared light changes. A far-infrared light source according to the present invention is configured so that the variation in the emission angle of far-infrared light in a nonlinear optical crystal when the frequency of the far-infrared light changes is substantially offset by the variation in the refractive angle of the far-infrared light at the interface between the nonlinear optical crystal and a prism when the frequency of the far-infrared light changes (see FIG. 8).

An optical assembly for the illumination and hyperspectral evaluation of an object, having a light source or an optical element at which a light source radiates, wherein the light source or the optical element is designed to divide pairs of unambiguously assignable photons into a first light beam and a second light beam so that the first light beam hits a first detector system and the second light beam is directed at an object and light radiation coming from the object is directed at an optical element which spectrally decomposes light radiation and, from the optical element spectrally decomposing said light radiation, is directed at a second detector system. The first light beam can also be directed at a spectrally decomposing optical element and, from there, at a first detector system, and the light radiation coming from the object can be directed directly at the second detector system. The first detector system is designed to perform a spatially resolved sensing of the first light beam, and the first detector system or the second detector system is designed to perform a spectrally resolved sensing of the second light beam. The detector systems are connected to an electronic evaluation unit, by means of which the measurement signals captured with spatial and spectral resolution are associated. The first and second light beams are spectrally, spatially and temporally correlated.

The sample imaging apparatus includes: an imaging unit that images a sample by using an achromatic lens in which longitudinal chromatic aberration is corrected in a wavelength range of chemiluminescent light of the sample; an excitation light source (the first epi-illumination light source and/or the second epi-illumination light source) that irradiates the sample with excitation light for causing the sample to emit fluorescent light; and an imaging control unit that adjusts a focal length of the achromatic lens in each imaging in a case of imaging the single sample a plurality of times by changing a wavelength range of the fluorescent light emitted by the sample, and performs imaging in a wavelength order of the fluorescent light used for the imaging.

A light modulation device and a single-channel spectrum detection system are provided. The light modulation device includes: a light guide plate; a dispersing component configured to disperse received light into light of different wavelengths and to diffract the light of different wavelengths into the light guide plate at different angles; and a dynamic filtering component configured to prevent light of a selected wavelength in the light guide plate from entering the dynamic filtering component such that the light of the selected wavelength emits out from the light guide plate, and to make light of non-selected wavelengths in the light guide plate enter the dynamic filtering component such that the light of the non-selected wavelengths is filtered out from the light guide plate.

A smoke detector includes a laser light source to provide incident light. The smoke detector also includes a Fabry-Perot etalon to transmit some incoming light, which is produced from the incident light, as transmitted light. Smoke particles in a cavity of the Fabry-Perot etalon affect an intensity of one or more wavelengths of the transmitted light.

Provided herein is an apparatus for assessing a color characteristic of a gemstone. The apparatus comprises an optically opaque platform for supporting a sample gemstone to be assessed, a daylight-approximating light source to provide uniform illumination to the gemstone, an image capturing component, and a telecentric lens positioned to provide an image of the illuminated gemstone to the image capturing component. Also provided are methods of color analysis based on images collected using such an apparatus.

A sensor includes: a transmitting device which transmits radiation along a path to a medium, and a measuring device which receives measuring radiation resulting from an interaction of the transmitted radiation with the medium and determines a measurand of the medium, with which at least one property of the transmitted radiation interacting with the medium can be determined and/or monitored in a cost-effective, space-saving manner; a prism in the path, through which prism a first portion of the transmitted radiation propagates in the direction of the medium and at which a second portion of the transmitted radiation is reflected; and a reference detector which receives the second component reflected at the prism and provides an output signal representing at least one property of the second component of the transmitted radiation.

A characteristic information extraction method of a small-molecule volatile substance, including: dividing a surface-enhanced Raman scattering (SERS) spectrum of the small-molecule volatile substance to obtain n wavelength subintervals, where n is a positive integer; sampling the n wavelength subintervals through weighted bootstrap sampling (WBS) to obtain Wwavelength subintervals, where W is a positive integer less than n; and screening the W wavelength subintervals to obtain desired wavelength subintervals. This application also provides a rapid detection method and a portable detection system of a small-molecule volatile substance.

A gas measurement system as disclosed can include a coherent light source, which emits a light beam; a detector; a beam path formed between the light source) and the detector; and a gas cell arranged in the beam path such that the detector receives light transmitted through the gas cell. The gas cell can include a porous ceramic and have an optical path length which is a multiple of the actual layer thickness of the gas cell. A optical element can be arranged in the beam path between the light source and the gas cell with the light beam emitted by the light being widened and unfocussed as the light beam enters the gas cell.