A terahertz-wave generating element includes a waveguide including an electro-optic crystal; an optical coupling member that extracts a terahertz wave, which is generated from the electro-optic crystal as a result of light propagating through the waveguide, to a space; and at least two electrodes that cause a first-order electro-optic effect in the electro-optic crystal by applying an electric field to the waveguide so as to change a propagation state of the light propagating through the waveguide. A crystal axis of the electro-optic crystal of the waveguide is set such that the terahertz wave generated by a second-order nonlinear optical process and the light propagating through the waveguide are phase-matched.

The present invention provides a multispectral color imaging device, an automatic calibration method based on a reference reflective surface, and a method for eliminating background signals. A multispectral color imaging device including a light house module comprising a light source and a light intensity collection device surrounding the light source; an integrating sphere module including an integrating sphere, a light inlet on one side of the integrating sphere, a light outlet on the top of the integrating sphere, a sample holder gateway on the other side of the integrating sphere and a sample holder having access to the interior of the integrating sphere; and a filter wheel module including a camera, a filter wheel below the camera, and a lens below the filter wheel. The device and calibration methods of the present invention together improve the accuracy and stability of the measurement.

A device for determining the surface topology and associated color of a structure, such as a teeth segment, includes a scanner for providing depth data for points along a two-dimensional array substantially orthogonal to the depth direction, and an image acquisition means for providing color data for each of the points of the array, while the spatial disposition of the device with respect to the structure is maintained substantially unchanged. A processor combines the color data and depth data for each point in the array, thereby providing a three-dimensional color virtual model of the surface of the structure. A corresponding method for determining the surface topology and associate color of a structure is also provided.

A high-resolution spectral image fast acquisition apparatus comprises an illumination source, an objective lens, a beam splitter, a single shot spectral image acquisition assembly and a reference image acquisition assembly, wherein the objective lens is used to align a sample to be measured; the illumination source is used to project an illumination light onto the sample to be measured so that the sample to be measured is amplified by the objective lens; wherein one part of amplified light enters the single shot spectral image acquisition assembly so as to acquire a low-resolution spectral cube of the sample to be measured, and another part of the amplified light enters the reference image acquisition assembly to acquire a high-resolution spectral cube. The apparatus enables rapid access to high-resolution spectral images, thereby speeding up the process of using spectral images for medical diagnosis.

Systems and methods for determining one or more properties of a sample are disclosed. The systems and methods disclosed can be capable of measuring along multiple locations and can reimage and resolve multiple optical paths within the sample. The system can be configured with one-layer or two-layers of optics suitable for a compact system. The optics can be simplified to reduce the number and complexity of the coated optical surfaces, et al. on effects, manufacturing tolerance stack-up problems, and interference-based spectroscopic errors. The size, number, and placement of the optics can enable multiple simultaneous or non-simultaneous measurements at various locations across and within the sample. Moreover, the systems can be configured with an optical spacer window located between the sample and the optics, and methods to account for changes in optical paths due to inclusion of the optical spacer window are disclosed.

A device and method of enhancing terahertz wave signals based on a hollow metal waveguide are disclosed. Simple devices such as a beam splitter, multiple plane mirrors, a beam combiner and an adjustable delay system are used. Two laser beams having a wavelength of 800 nm split by the beam splitter generate a fixed time phase delay, and are converged in the hollow metal waveguide to sequentially overlap with pulse of a laser having a wavelength of 400 nm for nonlinear interaction to ionize gas in the optical fiber to generate terahertz waves. The hollow metal waveguide can converge and transmit the generated terahertz waves due to its total reflection characteristics.

A spectroscopy apparatus, a spectroscopy method, and a bio-signal measuring apparatus are provided. The spectroscopy apparatus may include: a dispersive element configured to divide an incident light into a plurality of lights having different output angles; and a filter array configured to divide the plurality of lights, with a higher spectral resolution than a spectral resolution of the dispersive element, and provide the divided plurality of lights to a detector.

Technologies for detecting absorption of electromagnetic radiation traveling through a measurement volume of interest are described herein. In a general embodiment, a laser is used to emit electromagnetic radiation through the measurement volume where absorption is desirably detected. An optical collector receives a portion of the radiation and directs a first fraction of the portion back to a gain medium of the laser, where the radiation is amplified and emitted again, and directs a second fraction to an optical sensor that can detect absorption in the measurement volume based upon attenuation of energy of the radiation. As the radiation feeds back to the gain medium and is emitted again, energy at attenuated wavelengths is amplified less than at other wavelengths. Thus, attenuation of energy of the radiation due to absorption in the measurement volume is cumulative, and relatively small absorptions are amplified, allowing smaller absorptions to be detected more easily.

An electronic device may have a display with a cover layer. An ambient light sensor may be aligned with an ambient light sensor window formed from an opening in a masking layer on the cover layer in an inactive portion of the display. To help mask the ambient light sensor window from view, the ambient light sensor window may be provided with a black coating that matches the appearance of surrounding masking layer material while allowing light to reach the ambient light sensor. The black coating may be formed from a black physical vapor deposition thin-film inorganic layer with a high index of refraction. An antireflection layer formed from a stack of dielectric layers may be interposed between the black thin-film inorganic layer and the display cover layer.

Systems and methods for determining one or more properties of a sample are disclosed. The systems and methods disclosed can be capable of measuring along multiple locations and can reimage and resolve multiple optical paths within the sample. The system can be configured with one-layer or two-layers of optics suitable for a compact system. The optics can be simplified to reduce the number and complexity of the coated optical surfaces, etalon effects, manufacturing tolerance stack-up problems, and interference-based spectroscopic errors. The size, number, and placement of the optics can enable multiple simultaneous or non-simultanous measurements at various locations across and within the sample. Moreover, the systems can be configured with an optical spacer window located between the sample and the optics, and methods to account for changes in optical paths due to inclusion of the optical spacer window are disclosed.