A multiband IR adjunct (MIRA) sensor to spectroscopically determine the content and the concentration of chemical composition of a targeted object, includes a sensor housing, a first front optics in a first optical channel, a second front optics in the first optical channel, an acousto-optic tunable filter (AOTF), a photo detector (PD), a set of back optics in the first optical channel that focuses polarized narrow-band light beams received from the AOTF device onto the PD, the PD converting the polarized narrow-band light beams into an electrical signal, and a data acquisition unit signal-connected to the PD, the data acquisition unit collecting the electrical signals. Multiple optical channels can be provided within the housing to analyze UV/VIS/near infrared (NIR), short-wavelength infrared (SWIR), mid-wavelength infrared (MWIR), and LWIR wavelength ranges respectively.

Optical spectrometers may be used to determine the spectral components of electromagnetic waves. Spectrometers may be large, bulky devices and may require waves to enter at a nearly direct angle of incidence in order to record a measurement. What is disclosed is an ultra-compact spectrometer with nanophotonic components as light dispersion technology. Nanophotonic components may contain metasurfaces and Bragg filters. Each metasurface may contain light scattering nanostructures that may be randomized to create a large input angle, and the Bragg filter may result in the light dispersion independent of the input angle. The spectrometer may be capable of handling about 200 nm bandwidth. The ultra-compact spectrometer may be able to read image data in the visible (400-600 nm) and to read spectral data in the near-infrared (700-900 nm) wavelength range. The surface area of the spectrometer may be about 1 mm.sup.2, allowing it to fit on mobile devices.

A spectral image capturing method using a spectral camera control device installed in aircraft, the method comprising: a) setting an exposure time of the spectral camera so that a current exposure time is determined (S2), b) determining whether or not either an amount of attitude change or an amount of position change of the spectral camera per exposure time exceeds a predetermined threshold based on a spatial resolution of the spectral camera (S4), c1) when exceeding the predetermined threshold, resetting the current exposure time to be shorter (S5), c2) when not exceeding the predetermined threshold, not resetting the current exposure time to be shorter, and d) capturing a spectral image in a snapshot mode with the spectral camera using the reset exposure time, wherein when the transmission wavelength of the liquid crystal tunable filter is switched while the aircraft is in a stationary flight, steps b) to d) are repeated.

A spectral image capturing method using a spectral camera control device installed in aircraft, the method comprising: a) setting an exposure time of the spectral camera so that a current exposure time is determined (S2), b) determining whether or not either an amount of attitude change or an amount of position change of the spectral camera per exposure time exceeds a predetermined threshold based on a spatial resolution of the spectral camera (S4), c1) when exceeding the predetermined threshold, resetting the current exposure time to be shorter (S5), c2) when not exceeding the predetermined threshold, not resetting the current exposure time to be shorter, and d) capturing a spectral image in a snapshot mode with the spectral camera using the reset exposure time, wherein when the transmission wavelength of the liquid crystal tunable filter is switched while the aircraft is in a stationary flight, steps b) to d) are repeated.

A photonic integrated circuit including an input for receiving input electromagnetic radiation having a bandwidth greater than 60 nm; a spectral splitter splitting the electromagnetic radiation into a plurality of spectral channels; a modulator for modulating an amplitude and a phase of one or more of the spectral channels so as to form modulated outputs; and a spectral recombiner for combining the modulated outputs into a single output port outputting output electromagnetic radiation having the desired output spectral intensity profile shaped by and synthesized from the modulated outputs.

A photonic integrated circuit including an input for receiving input electromagnetic radiation having a bandwidth greater than 60 nm; a spectral splitter splitting the electromagnetic radiation into a plurality of spectral channels; a modulator for modulating an amplitude and a phase of one or more of the spectral channels so as to form modulated outputs; and a spectral recombiner for combining the modulated outputs into a single output port outputting output electromagnetic radiation having the desired output spectral intensity profile shaped by and synthesized from the modulated outputs.

A method of operating a hyperspectral imaging device includes connecting electrodes on a liquid crystal variable retarder to a voltage source, rotating liquid crystal material in the liquid crystal variable retarder between a first orientation with a certain optical phase delay and a second orientation with a different optical phase delay, receiving a beam of light at an image sensor that has passed through the liquid crystal variable retarder, and producing an output signal from the image sensor.

The invention relates to a photometer (30) for analysing the composition of a sample gas. The photometer comprises an infra-red (IR) source (20) configured to direct a first plurality of pulses (40) of IR radiation through the sample gas to an IR detector (26), at least two of the first plurality of pulses being of different wavelength. The photometer further comprises an ultraviolet (UV) source (32) configured to generate a second plurality of pulses (38) of UV radiation for conveyance to a UV detector (36), at least two of the second plurality of pulses being of different wavelength. A path selection arrangement (22, 42-50) is configured to selectively convey different ones of the second plurality of pulses (38) to one of the sample gas and the UV detector (36). The photometer further comprises processing circuitry coupled to the IR source (20), the UV source (32), the IR detector (26), the UV detector (36) and the path selection arrangement (22, 42-50). The processing circuitry is configured to (i) select the wavelength to be used for a given UV pulse of the second plurality of pulses (38), (ii) receive a plurality of detection signals from each of the IR detector (26) and the UV detector (36) and (iii) based on the detection signals, determine a concentration of at least one component of the sample gas. A method for analysing the composition of a sample gas is also disclosed.

The invention relates to a photometer (30) for analysing the composition of a sample gas. The photometer comprises an infra-red (IR) source (20) configured to direct a first plurality of pulses (40) of IR radiation through the sample gas to an IR detector (26), at least two of the first plurality of pulses being of different wavelength. The photometer further comprises an ultraviolet (UV) source (32) configured to generate a second plurality of pulses (38) of UV radiation for conveyance to a UV detector (36), at least two of the second plurality of pulses being of different wavelength. A path selection arrangement (22, 42-50) is configured to selectively convey different ones of the second plurality of pulses (38) to one of the sample gas and the UV detector (36). The photometer further comprises processing circuitry coupled to the IR source (20), the UV source (32), the IR detector (26), the UV detector (36) and the path selection arrangement (22, 42-50). The processing circuitry is configured to (i) select the wavelength to be used for a given UV pulse of the second plurality of pulses (38), (ii) receive a plurality of detection signals from each of the IR detector (26) and the UV detector (36) and (iii) based on the detection signals, determine a concentration of at least one component of the sample gas. A method for analysing the composition of a sample gas is also disclosed.

A filter and a miniature spectrum measuring device are provided. The filter includes a plurality of film structures. Each of the film structures includes an H-type structural film, an L-type structural film, and a cavity film disposed between the H-type structural film and the L-type structural film.