The invention relates to an optical system, to a spectrometer device comprising such optical system and to a method to operate such an optical system comprising an entrance aperture for entering primary light containing both a first, lower wavelength range and a second, higher wavelength range into said optical system, a grating for spectral dispersion of the primary light beam into a first fan of diffracted light within the first wavelength range and a primary zero order light beam, a mirror element suitably positioned to reflect the primary zero order light beam back as secondary light beam to the grating where it is dispersed into a second fan of diffracted light within the second wavelength range, a detector arrangement with detectors, an absorber element to be reversibly placed within the primary zero order light beam, and a filter element to be reversibly placed within the primary light beam.

A method includes directing a first plurality of probe laser pulses through a sample, dividing each of the first plurality of probe laser pulses to generate a first interferogram, and generating first image data reproducible as a first phase image of the sample. A plurality of pump laser bursts are directed onto the sample to heat the sample. A second plurality of probe laser pulses are directed through the sample at a predetermined time delay. Each of the second plurality of probe laser pulses are divided to generate a second interferogram. Second image data is generated that is reproducible as a second phase image of the sample. A transient phase shift is determined in the second phase image relative to the first phase image. A vibrational spectroscopy property is determined of the sample based on the transient phase shift, thereby allowing an identification of chemical bond information of within the sample.

Various embodiments disclosed herein describe a divided-aperture infrared spectral imaging (DAISI) system that is adapted to acquire multiple IR images of a scene with a single-shot (also referred to as a snapshot). The plurality of acquired images having different wavelength compositions that are obtained generally simultaneously. The system includes at least two optical channels that are spatially and spectrally different from one another. Each of the at least two optical channels are configured to transfer IR radiation incident on the optical system towards an optical FPA unit comprising at least two detector arrays disposed in the focal plane of two corresponding focusing lenses. The system further comprises at least one temperature reference source or surface that is used to dynamically calibrate the two detector arrays and compensate for a temperature difference between the two detector arrays.

Various embodiments disclosed herein describe a divided-aperture infrared spectral imaging (DAISI) system that is adapted to acquire multiple IR images of a scene with a single-shot (also referred to as a snapshot). The plurality of acquired images having different wavelength compositions that are obtained generally simultaneously. The system includes at least two optical channels that are spatially and spectrally different from one another. Each of the at least two optical channels are configured to transfer IR radiation incident on the optical system towards an optical FPA unit comprising at least two detector arrays disposed in the focal plane of two corresponding focusing lenses. The system further comprises at least one temperature reference source or surface that is used to dynamically calibrate the two detector arrays and compensate for a temperature difference between the two detector arrays.

A spectral imaging system configured to obtain spectral measurements in a plurality of spectral regions is described herein. The spectral imaging system comprises at least one optical detecting unit having a spectral response corresponding to a plurality of absorption peaks of a target chemical species. In an embodiment, the optical detecting unit may comprise an optical detector array, and one or more optical filters configured to selectively pass light in a spectral range, wherein a convolution of the responsivity of the optical detector array and the transmission spectrum of the one or more optical filters has a first peak in mid-wave infrared spectral region between 3-4 microns corresponding to a first absorption peak of methane and a second peak in a long-wave infrared spectral region between 6-8 microns corresponding to a second absorption peak of methane.

A system for monitoring a petrochemical installation is disclosed. The system can include an optical imaging system comprising an array of optical detectors. The system can comprise processing electronics configured to process image data detected by the optical imaging system. The processing electronics can be configured to detect a target species based at least in part on the processed image data. The processing electronics can further be configured to, based on a detected amount of the target species, transmit an alarm notification to an external computing device over a communications network indicating that the target species has been detected at the petrochemical installation.

A method for retrieving a corrected spectrum from a measured spectrum (e.g., retrieving a top-of-water spectrum from a measured top-of-atmosphere spectrum) includes creating a scene-specific model of a region of interest and performing a ray-tracing simulation to simulate rays of light that would reach an airborne (or spaceborne) sensor. The region of interest can be an optically complex area such as an inland or coastal body of water. Based on the ray-tracing simulation, a scene-specific correction for unwanted effects (e.g., adjacency effects, variable atmospheric conditions, and/or other suitable effects) is obtained. A corrected spectrum is obtained by correcting the measured spectrum using the scene-specific correction. The ray-tracing simulation may be performed using a graphical processing unit, allowing the scene-specific correction to be performed in real time or near real time.

In one embodiment, an infrared (IR) imaging system for determining a concentration of a target species in an object is disclosed. The imaging system can include an optical system including an optical focal plane array (FPA) unit. The optical system can have components defining at least two optical channels thereof, said at least two optical channels being spatially and spectrally different from one another. Each of the at least two optical channels can be positioned to transfer IR radiation incident on the optical system towards the optical FPA. The system can include a processing unit containing a processor that can be configured to acquire multispectral optical data representing said target species from the IR radiation received at the optical FPA. Said optical system and said processing unit can be contained together in a data acquisition and processing module configured to be worn or carried by a person.

A spectrometer may include a radiation source having a spark generator, an entrance slit, a dispersive element and a plurality of detectors, and a rotatable sector shutter having an axis of rotation and a trigger unit optically coupled to the sector diaphragm. The axis of rotation of the sector shutter is non-parallel to a connecting line between the source and the entrance slit.

An example system for inspecting a surface includes a laser, an optical system, a gated camera, and a control system. The laser is configured to emit pulses of light, with respective wavelengths of the pulses of light varying over time. The optical system includes at least one optical element, and is configured to direct light emitted by the laser to points along a scan line one point at a time. The gated camera is configured to record a fluorescent response of the surface from light having each wavelength of a plurality of wavelengths at each point along the scan line. The control system is configured to control the gated camera such that an aperture of the gated camera is open during fluorescence of the surface but closed during exposure of the surface to light emitted by the laser.