A method and apparatus is provided for implementing a parametric down-conversion (PDC)-based calibration comprising calibrating a measuring instrument; disposing a pinhole at a position of a light-emitting sample for which the measuring instrument needs to be calibrated; irradiating a nonlinear crystal with a light source; setting the nonlinear crystal by ensuring a phase-matching wavelength of the nonlinear crystal is set at one boundary of a desired bandwidth; acquiring one or more PDC spectrums by the measuring instrument; obtaining peak values and their corresponding wavelengths from each acquired spectrum; and obtaining a response function based on the peak values and corresponding wavelengths.

Provided are a dual coupler device configured to receive lights of different polarization components, a spectrometer including the dual coupler device, and a non-invasive biometric sensor including the spectrometer. The dual coupler device may include, for example, a first coupler layer configured to receive a light of a first polarization component among incident lights. and a second coupler layer configured to receive a light of a second polarization component among the incident lights, wherein a polarization direction of the light of the first polarization component is perpendicular to a polarization direction of the light of the second polarization component. The first coupler layer and the second coupler layer may be spaced apart from each other and extended along a direction in which the light propagates in the first coupler layer and the second coupler layer.

A method and apparatus is provided for implementing a parametric down-conversion (PDC)-based calibration comprising calibrating a measuring instrument; disposing a pinhole at a position of a light-emitting sample for which the measuring instrument needs to be calibrated; irradiating a nonlinear crystal with a light source; setting the nonlinear crystal by ensuring a phase-matching wavelength of the nonlinear crystal is set at one boundary of a desired bandwidth; acquiring one or more PDC spectrums by the measuring instrument; obtaining peak values and their corresponding wavelengths from each acquired spectrum; and obtaining a response function based on the peak values and corresponding wavelengths.

Provided are a dual coupler device configured to receive lights of different polarization components, a spectrometer including the dual coupler device, and a non-invasive biometric sensor including the spectrometer. The dual coupler device may include, for example, a first coupler layer configured to receive a light of a first polarization component among incident lights. and a second coupler layer configured to receive a light of a second polarization component among the incident lights, wherein a polarization direction of the light of the first polarization component is perpendicular to a polarization direction of the light of the second polarization component. The first coupler layer and the second coupler layer may be spaced apart from each other and extended along a direction in which the light propagates in the first coupler layer and the second coupler layer.

A method of calibrating a hyperspectral imaging device includes illuminating a hyperspectral imaging sensor with a light source having known spectral properties, sampling the light from the light source with the hyperspectral imaging sensor to obtain sampled spectral properties, and calibrating a performance characteristic of the hyperspectral imaging sensor based upon comparing the sampled spectral properties of the light source to the known spectral properties.

A method of calibrating a hyperspectral imaging device includes illuminating a hyperspectral imaging sensor with a light source having known spectral properties, sampling the light from the light source with the hyperspectral imaging sensor to obtain sampled spectral properties, and calibrating a performance characteristic of the hyperspectral imaging sensor based upon comparing the sampled spectral properties of the light source to the known spectral properties.

A method of operating a hyperspectral imaging device includes receiving a light beam at a liquid crystal retarding device, and driving the liquid crystal retarding device with a pre-computed voltage waveform, wherein the voltage waveform is selected to reach a target optical retardance over time for the liquid crystal retarding device.

An optical assembly is disclosed including two laterally variable bandpass optical filters slacked at a fixed distance from each other, so that the upstream filter functions as a spatial filler for the downstream filter. The lateral displacement may cause a suppression of the oblique beam when transmission passbands at impinging locations of the oblique beam onto the upstream and downstream filters do not overlap. A photodetector array may be disposed downstream of the downstream filter. The optical assembly may be coupled via a variety of optical conduits or optical fibers for spectroscopic measurements of a flowing sample.

Provided are a hyperspectral sensor and a hyperspectral camera in which influence of external information such as a reflecting material is reduced such that the spectral data accuracy of a subject to be acquired can be improved. In the hyperspectral sensor in which light from a subject is split into light components in a plurality of wavelength ranges by a spectral optical element and each of the light components in the wavelength ranges is received by a sensor array consisting of a plurality of photodetection elements to acquire spectral data in which spectral information of the subject is associated with each of the photodetection elements, a polarization diffraction element that emits polarized light is used as the spectral optical element.

An optical assembly is disclosed including two laterally variable bandpass optical filters stacked at a fixed distance from each other, so that the upstream filter functions as a spatial filter for the downstream filter. The lateral displacement may cause a suppression of the oblique beam when transmission passbands at impinging locations of the oblique beam onto the upstream and downstream filters do not overlap. A photodetector array may be disposed downstream of the downstream filter. The optical assembly may be coupled via a variety of optical conduits or optical fibers for spectroscopic measurements of a flowing sample.