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 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.

An optical system for a hyperspectral camera and a hyperspectral camera comprising such an optical system are disclosed. The optical system comprises fore optics (1000), an image sensor (1800), a slit (1500), relay optics (1200), a first optical element (2000) positioned before the slit (1500), where the first optical element (2000) is defocusing light in a direction parallel to the slit (1500) while keeping focus in a direction perpendicular to the slit (1500); and a second optical element (2100) positioned after the slit (1500), where the second optical element (2100) is compensating the defocus of the depicted scene introduced by the first element (2000).

An imaging apparatus includes an image sensor, a filter array disposed on an optical path from a target object to the image sensor and including two-dimensionally-arranged optical filters, and a processing circuit that generates at least four pieces of spectral image data based on an image acquired by the image sensor. The optical filters include various types of optical filters with different spectral transmittance. Each of the at least four pieces of spectral image data indicates an image corresponding to one of at least four wavelength bands. The filter array includes at least one characteristic section. The processing circuit detects a relative position between the filter array and the image sensor based on the at least one characteristic section in the image acquired by the image sensor, and compensates for deviation between the relative position and a preliminarily-set relative position when the processing circuit detects the deviation.

Aspects of the present disclosure provide a method for wavelength calibration of a spectrometer. The method can include receiving a calibration light signal having first spectral components of different first wavelengths; separating and projecting the first spectral components onto pixels of a detector of the spectrometer; establishing a relation between the first wavelengths and pixel numbers of first pixels on which the first spectral components are projected; calculating first residual errors between the first wavelengths and estimated wavelengths that are associated by the relation to the pixel numbers of the first pixels; receiving an optical signal having a second spectral component of a second wavelength; projecting the optical signal onto a second pixel; and calibrating the second wavelength based on a second residual error calculated based on one of the first residual errors that corresponds to a pair of the first pixels between which the second pixel is located.

A reference imaging system including a planar reference piece. The reference imaging system further includes a three-axis gantry for positioning the planar reference piece at a plurality of points in a 3D coordinate system. Additionally, the reference imaging system includes a yaw actuator for adjusting the yaw angle of the object. Furthermore, the reference imaging system includes a pitch actuator for adjusting the pitch of the object. Moreover, the reference imaging system includes a computer processing unit for controlling the 3D position, pitch and yaw of the planar reference piece.

Disclosed are embodiments of an improved apparatus and system, and associated methods for optically diagnosing a semiconductor manufacturing process. A hyperspectral imaging system is used to acquire spectrally-resolved images of emissions from the plasma, in a plasma processing system. Acquired hyperspectral images may be used to determine the chemical composition of the plasma and the plasma process endpoint. Alternatively, a hyperspectral imaging system is used to acquire spectrally-resolved images of a substrate before, during, or after processing, to determine properties of the substrate or layers and features formed on the substrate, including whether a process endpoint has been reached; or before or after processing, for inspecting the substrate condition.

Apparatus and methods for creating deposits of uniformly spaced or uniformly overlapping droplets of selected chemicals where each droplet has an a priori known amount of the selected chemical or chemicals is taught (including biological and microbial materials). In some embodiments the deposits may be used as samples of different but known concentrations that may be used to calibrate spectroscopic inspection instruments to enable such instruments to not only provide identification in situ of unknown materials but also to provide calibrated and traceable surface concentrations of such materials. In some embodiments, such calibrated instruments may be used in enhanced processes for validating the cleanliness of manufacturing surfaces such as surfaces of equipment used in the preparation of pharmaceuticals, food, or semiconductor devices. Such instruments may be used to ensure adequate purity, or non-contamination, of surfaces of products themselves or packaging materials or of locations where such products will be used. Such calibrated instruments may also be useful in detecting cleanliness of non-manufacturing surfaces where contamination may be of concern, whether they be public or private spaces such as laboratories, restaurants, airports, satellites or other spacecraft. In some embodiments, such instruments may range from deep UV instruments to far infrared instruments or beyond.

Aspects of the present disclosure provide a method for wavelength calibration of a spectrometer. The method can include receiving a calibration light signal having first spectral components of different first wavelengths; separating and projecting the first spectral components onto pixels of a detector of the spectrometer; establishing a relation between the first wavelengths and pixel numbers of first pixels on which the first spectral components are projected; calculating first residual errors between the first wavelengths and estimated wavelengths that are associated by the relation to the pixel numbers of the first pixels; receiving an optical signal having a second spectral component of a second wavelength; projecting the optical signal onto a second pixel; and calibrating the second wavelength based on a second residual error calculated based on one of the first residual errors that corresponds to a pair of the first pixels between which the second pixel is located.

An apparatus for measuring time-resolved optical spectrum includes a light source, a sensor for collecting, forming, manipulating and measuring the intensity of the optical radiation, and a controller coupled to the light source and sensor. The sensor includes at least one optical delay element to provide a time delay to a first portion of the optical radiation. The sensor arrangement further includes an optical spectral disperser to split the delayed first portion and the second portion of the optical radiation into dispersed radiation having a plurality of wavelengths, and a sensor element configured to receive each wavelength of the dispersed radiation on a different spatial region, and measure the light intensity associated with each wavelength of the dispersed radiation. The controller collects the light intensity associated with each wavelength of the dispersed radiation measured by the sensor element to form a time-resolved optical spectrum.