A configuration of the present disclosure specifies a signal point of a specific component and a background point, based on time series two-dimensional spectroscopic image data of a gas; calculates a correlation coefficient between a time series detection signal at the signal point and a time series detection signal at the background point; and generates a time series detection signal of the specific component, based on a corrected time series detection signal obtained by subtracting a product of the correlation coefficient and the time series detection signal at the background point from the time series detection signal at the signal point.

Configurations for light source modules and methods for mitigating coherent noise are disclosed. The light source modules may include multiple light source sets, each of which may include multiple light sources. The light emitted by the light sources may be different wavelengths or the same wavelength depending on whether the light source module is providing redundancy of light sources, increased power, coherent noise mitigation, and/or detector mitigation. In some examples, the light source may emit light to a coupler or a multiplexer, which may then be transmitted to one or more multiplexers. In some examples, the light source modules provide one light output and in other examples, the light source modules provide two light outputs. The light source modules may provide light with approximately zero loss and the wavelengths of light may be close enough to spectroscopically equivalent respect to a sample and far enough apart to provide coherent noise mitigation.

In an example, an Echelle grating wavelength division multiplexing (WDM) device includes a first waveguide, a slab waveguide, multiple second waveguides, an Echelle grating, and a metal-filled trench. The first waveguide includes either an input waveguide or an output waveguide. The multiple second waveguides are optically coupled to the first waveguide through the slab waveguide. The multiple second waveguides include multiple output waveguides if the first waveguide includes the input waveguide or multiple input waveguides if the first waveguide includes the output waveguide. The Echelle grating includes multiple grating teeth formed in the slab waveguide. The metal-filled trench forms a mirror at the grating teeth to reflect incident light from the first waveguide toward the multiple second waveguides or from the multiple second waveguides toward the first waveguide.

A spectrograph that includes camera focusing optics with a primary mirror having a concave-shaped reflective mirror surface, a secondary mirror having a convex-shaped reflective mirror surface and positioned to receive light reflected by the primary mirror, a tertiary mirror having a concave reflective mirror surface and positioned to receive light reflected by the secondary mirror, and a field correcting lens comprising a convex lens surface in combination with a concave lens surface, wherein light received by said field correcting lens from said tertiary mirror enters said convex lens surface, traverses said field correcting lens, and exits from said concave lens surface. The optional field correcting lens is positioned such that the primary mirror, secondary mirror, tertiary mirror, and the field correcting lens share the common parent vertex axis.

An imaging spectrometer receives a beam of light from a slit and outputs the beam of light to a focal plane. The output beam of light at the focal plane is dispersed in accordance with a spectral composition of the beam of light received from the slit. The imaging spectrometer comprises first to fourth curved reflective portions. The first to fourth curved reflective portions are arranged so that the beam of light, in its passage from the slit to the focal plane, sequentially strikes the first to fourth curved reflective portions and is reflected by the first to fourth curved reflective portions. Further, the first to fourth curved reflective portions are alternatingly concave or convex, respectively, along the passage of the beam of light. At least one of the first to fourth curved reflective portions has a reflective grating structure. Further disclosed is a method of manufacturing such imaging spectrometer.

A method of determining a peak intensity in an optical spectrum is described. The method includes producing a two-dimensional array of spectrum values by imaging the optical spectrum onto a detector array. An offset using an actual location and an expected location of a peak of an interpolated subarray is used to adjust an expected location of another peak that is within another two-dimensional subarray. Interpolated spectrum values are then used to produce a peak intensity value of the second peak.

Configurations for light source modules and methods for mitigating coherent noise are disclosed. The light source modules may include multiple light source sets, each of which may include multiple light sources. The light emitted by the light sources may be different wavelengths or the same wavelength depending on whether the light source module is providing redundancy of light sources, increased power, coherent noise mitigation, and/or detector mitigation. In some examples, the light source may emit light to a coupler or a multiplexer, which may then be transmitted to one or more multiplexers. In some examples, the light source modules provide one light output and in other examples, the light source modules provide two light outputs. The light source modules may provide light with approximately zero loss and the wavelengths of light may be close enough to spectroscopically equivalent respect to a sample and far enough apart to provide coherent noise mitigation.

Disclosed herein are spectrometer support systems, as well as related methods, computing devices, and computer-readable media. For example, in some embodiments, a spectrometer support apparatus may: receive, for each of a plurality of calibration samples of an analyte at different known concentrations, an array of spectrometer output intensities of the calibration sample, wherein different ones of the spectrometer output intensities in the array are associated with data representative of different deflection amounts; train a machine-learning computational model, using the plurality of known concentrations of the analyte in the calibration samples and the associated plurality of arrays of spectrometer output intensities, to output a concentration of the analyte in a target sample based on an input array of spectrometer output intensities of the target sample; and use the trained machine-learning computational model as a calibration model for the analyte for subsequent spectrometer operation.

A spectrograph that includes a first mirror having flat a mirror reflective surface and positioned to reflect light traversing a prism, a second mirror having a concave-shaped reflective mirror surface and positioned to reflect light received from the first mirror, a third mirror having a convex-shaped reflective mirror surface and positioned to receive light reflected by the second mirror, a fourth mirror having a spheroidal reflective mirror surface and positioned to receive light reflected by the third mirror, and a field lens comprising a concave mirror surface in combination with a convex mirror surface, wherein light received by said field lens from said fourth mirror enters said convex mirror surface, traverses said field lens, and exits from said concave mirror surface. The fifth mirror is positioned such that the second mirror, third mirror, fourth mirror, and fifth mirror share a common vertex axis.

A peak position measurement offset is determined in a two-dimensional optical spectrum. A plurality of peaks are identified that appear in both a spectrum obtained from a reference material at known conditions and a spectrum obtained from a sample of interest. The peak position measurement offset is determined by a comparison of a pattern formed by peak positions of the plurality of identified peaks in the spectrum obtained from the sample of interest against the plurality of identified peaks in the spectrum obtained from the reference material.