A compact spectrometer is disclosed that is suitable for use in mobile devices such as cellular telephones. In preferred embodiments, the spectrometer comprises a filter, at least one Fourier transform focusing element, a micro-lens array, and a detector, but does not use any dispersive elements. Methods for using the spectrometer as an end-user device for performing on-site determinations of food quality, in particular, by comparison with an updatable database accessible by all users of the device, are also disclosed.

A spectroscopic camera includes: a spectral filter having an optical area that transmits light with a predetermined wavelength from incident light; an image sensor receiving transmitted light transmitted through the spectral filter; and a casing accommodating the spectral filter and the image sensor. A direction in which the incident light enters is a first direction. The casing includes: a cylindrical lens mount which a lens that the incident light enters is attachable to and removable from and which has a center axis along the first direction; a wall having an aperture that has an aperture center coaxial with the center axis of the lens mount and that is smaller than a cylindrical inner diameter of the lens mount and equal to or smaller than an outer diameter of the optical area; a filter accommodation unit accommodating the spectral filter at such a position that the optical area covers the aperture, as viewed in a plan view along the first direction; and an imaging sensor accommodation unit provided downstream of the filter accommodation unit in the first direction and accommodating the image sensor at such a position that the image sensor overlaps the aperture as viewed in the plan view.

According to an example aspect of the present invention, there is provided a method for analysing a chemical composition of a target, the method comprising placing an electrically tunable Fabry-Perot interferometer in a path of radiation emitted by a radiation source, and detecting the radiation, which has passed the Fabry-Perot interferometer and which has passed or was reflected by the target, by means of a detector, and wherein detection is made such that multiple pass bands are allowed to be detected simultaneously.

According to an example aspect of the present invention, there is provided a method for analysing a chemical composition of a target, the method comprising placing an electrically tunable Fabry-Perot interferometer in a path of radiation emitted by a radiation source, and detecting the radiation, which has passed the Fabry-Perot interferometer and which has passed or was reflected by the target, by means of a detector, and wherein detection is made such that multiple pass bands are allowed to be detected simultaneously.

Systems and methods for measuring a temperature using an optical whispering gallery mode (WGM) resonator are disclosed. The system includes a WGM resonator operatively coupled to a tunable laser source and a detector, as well as a computing device. The computing device is configured to transform a transmission spectrum from the detector into a measured barcode that includes a matrix of values indicative of at least one characteristic of the transmission spectrum. The computing device is further configured to transform the measured barcode into a temperature based on a relative collective shift of the measured barcode from a reference barcode selected from a predetermined library of reference barcodes.

A user device for imaging a scene includes a first plurality of optical sensors coupled to a substrate for collecting an image of a scene and a second plurality of optical sensors coupled to the substrate for collecting spectral information from the image. A plurality of sets of interference filters are associated with the second plurality of optical sensors, where each interference filter of a set of interference filters is configured to pass light in one of a plurality of wavelength ranges to one or more optical sensors of the second plurality of optical sensors and each optical sensor of the plurality of optical sensors is associated with a spatial area of the image. A processor is adapted to receive an output from the first plurality of optical sensors and the second plurality of optical sensors and determine, based on the spectral information, a target area within the scene. The processor is further adapted to retrieve focus data for the scene, determine a focus distance for the target area and output user-perceptible information to an output display.

In an illustrative configuration, a method for monitoring air quality is disclosed. The method includes accepting analyte gas into a cell and reflecting light rays into the analyte gas repeatedly across the cell into at least one sensor. The light scattered by particulate matter in the analyte gas and amount of spectra-absorption due to presence of a gaseous chemical is then measured. Based on the determined amount of spectra-absorption and the measured scattered light the gaseous chemical is then measured.

A processing apparatus is connected to one or more terminals including a hyperspectral sensor that generates compressed image data which is hyperspectral information of a target compressed as two-dimensional image information over a network. The processing apparatus includes a storage device that stores data sets of samples and a first reconstruction table for generating hyperspectral data from the compressed image data, the data set of each sample includes hyperspectral data of the sample and data indicative of a property value of the sample; and a processing circuit that generates a statistical model for estimating the property value from the hyperspectral data on the basis of the data sets of the samples and generates a second reconstruction table by editing the first reconstruction table in accordance with the statistical model thus generated.

A spectral filter may include a plurality of filter arrays each including a plurality of unit filters having different center wavelengths from each other. Each of the plurality of unit filters may include a first metal reflection layer and a second metal reflection layer which are disposed to be apart from each other; a cavity including a first pattern and being arranged between the first metal reflection layer and the second metal reflection layer; and a lower pattern film being disposed under the first metal reflection layer and including a second pattern. In unit filters having a same center wavelength in each of the plurality of unit filters corresponding to the plurality of filter arrays, the first pattern of the cavity and the second pattern of the lower pattern film may vary according to a position of the unit filters.

A method and a system for interrogating an optical fiber includes a probe signal that has a first frequency comb at a first repetition rate (Δf) injected into the optical fiber. A backscattering signal that includes the probe signal convolved with an impulse response of the optical fiber in reflection which is sensitive to at least one parameter being measured from the optical fiber is gathered. The backscattering signal is beaten with a local oscillator signal to generate a beating signal, the local oscillator signal including a second frequency comb at a second repetition rate that is offset from the first repetition rate (Δf+δf) and being mutually coherent with the first frequency comb. The resulting beating signal is analysed to thereby determine the at least one parameter being measured from the optical fiber.