In swept source Raman (SSR) spectroscopy, a swept laser beam illuminates a sample, which inelastically scatters some of the incident light. This inelastically scattered light is shifted in wavelength by an amount called the Raman shift. The Raman-shifted light can be measured with a fixed spectrally selective filter and a detector. The Raman spectrum can be obtained by sweeping the wavelength of the excitation source and, therefore, the Raman shift. The resolution of the Raman spectrum is determined by the filter bandwidth and the frequency resolution of the swept source. An SSR spectrometer can be smaller, more sensitive, and less expensive than a conventional Raman spectrometer because it uses a tunable laser and a fixed filter instead of free-space propagation for spectral separation. Its sensitivity depends on the size of the collection optics. And it can use a nonlinearly swept laser beam thanks to a wavemeter that measures the beam's absolute wavelength during Raman spectrum acquisition.

The present disclosure relates to a mobile terminal having a lighting unit and a control method thereof. A mobile terminal according to one implementation includes a lighting unit, a camera, and a controller configured to control the lighting unit to irradiate illumination light to a subject to be captured through the camera, and control the camera to capture the subject irradiated with the illumination light, wherein the controller is configured to determine a material of the subject based on information related to the illumination light irradiated on the subject captured through the camera.

An optical density measuring apparatus for measuring density of a gas or a liquid to be measured includes a light source capable of irradiating light into a core layer, a detector capable of receiving light propagated through the core layer, and an optical waveguide that includes a substrate and the core layer. The core layer includes a light propagation unit and a first diffraction grating unit that receives light from the light source and guides the light to the light propagation unit, which includes a propagation channel capable of propagating light in an extending direction of the light propagation unit. The first diffraction grating unit is disposed near to and facing a light-emitting surface of the light source. The first diffraction grating unit includes first diffraction gratings, at least two of which receive light emitted from the same light-emitting surface of the light source.

A mid-infrared gas sensor based on a tapered sub-wavelength grating slot waveguide comprises a lower cladding, a first tapered grating array and a second tapered grating array. The first tapered grating array and the second tapered grating array are disposed on an upper surface of the lower cladding. The first tapered grating array is located in front of the second tapered grating array. The first tapered grating array is formed by 5566 identical first core waveguides that are regularly distributed at intervals from left to right. The second tapered grating array is formed by 5566 identical second core waveguides that are regularly distributed at intervals from left to right. The first core waveguides and the second core waveguides are tapered waveguides. Upper sides and lower sides of the first core waveguides and the second core waveguides are isosceles trapezoids.

Herein are described data acquisition systems and methods applying such systems to determine three-dimensional (3D) diffusion tensors, and simultaneously, to perform 3D structure imaging. Example data acquisition systems can include computing systems in communication with modified light sheet microscopes that are configured for high-speed volumetric imaging to record 3D diffusion processes and high-resolution 3D structural imaging.

A microfluidic apparatus is provided. The microfluidic apparatus includes a first substrate having a first side and a second side opposite to each other; a grating layer on the second side of the first substrate, the grating layer including a plurality of grating blocks of different wavelength selectivity; a second substrate having a third side and a fourth side opposite to each other; the fourth side of the second substrate on a side of the third side away from the first substrate, and the second side of the first substrate on a side of the first side away from the second substrate; a light detection layer on the third side of the second substrate, the light detection layer including a plurality of detectors; and a microfluidic layer between the first substrate and the light detection layer, the microfluidic layer including a plurality of microfluidic channels.

A metrology system configured to measure overlay errors on a sample is disclosed. The metrology system measures overlay error on the sample in a first direction and/or a second direction simultaneously or sequentially. The metrology system comprises an illumination sub-system configured to illuminate a hatched overlay target on the sample with one or more illumination lobes. The metrology system further comprises an objective lens and a detector at an image plane configured to image the hatched overlay target. A controller is configured to direct illumination source to generate the illumination lobes, receive images of the hatched overlay target, and calculate the overlay errors between a first layer of the sample and a second layer of the sample.

A particle characterisation instrument, comprising a light source, a sample cell, an optical element between the light source and sample cell and a detector. The optical element is configured to modify light from the light source to create a modified beam, the modified beam: a) interfering with itself to create an effective beam in the sample cell along an illumination axis and b) diverging in the far field to produce a dark region along the illumination axis that is substantially not illuminated at a distance from the sample cell. The detector is at the distance from the sample cell, and is configured to detect light scattered from the effective beam by a sample in the sample cell, the detector positioned to detect forward or back scattered light along a scattering axis that is at an angle of 0° to 10° from the illumination axis.

Embodiments relate generally to electromagnetic radiation detector devices, systems, and methods using a planar Golay cell. A method for gas detection may comprise providing a gas sealed in a cavity of a gas detector; directing radiative power from a light source through one or more target gases and through a cell body of the gas detector toward the cavity and a wavelength selective absorber of the gas detector, wherein the one or more target gases are located between the light source and the cavity; setting wavelength sensitivity with the wavelength selective absorber, wherein the wavelength sensitivity is irrespective of an angle of incidence (?); absorbing the radiative power by the wavelength selective absorber and by the one or more target gases; detecting, by a pressure sensing element, a pressure change caused by the absorbing of the radiative power; and determining the one or more target gases based on the detected pressure change.

A diffractive biosensor for the selective detection of biomolecules includes a substrate and an optical biograting situated on the substrate, the biograting having periodically arranged receptors for the biomolecules and the efficiency of a diffraction of incident light, and thus the intensity of a measuring light beam arriving in a detector, is a function of a mass coverage of the biograting with the biomolecules to be detected. The biosensor has a device for generating a reference light beam directed to the detector, by which the phase position of stray light arriving in the detector is able to be determined.