G01J2003/4538

Compact Computational Spectrometer Using Solid Wedged Low Finesse Etalon

A two-layer hybrid solid wedged etalon was fabricated and combined with a traditional imager to make a compact computational spectrometer. The hybrid wedge was made of Nb.sub.2O.sub.5 and Infrasil 302 and was designed to operate from 0.4-2.4 μm. Initial demonstrations used a CMOS imager and operated from 0.4-0.9 μm with spectral resolutions<30 cm.sup.−1 from single snapshots. The computational spectrometer operates similarly to a spatial Fourier Transform infrared (FTIR) spectrometer with spectral reconstruction using a non-negative least squares fitting algorithm based on analytically computed wavelength response vectors determined from extracted physical thicknesses across the entire two-dimensional wedge. This computational technique resulted in performance and spectral resolutions exceeding those that could be achieved from Fourier techniques. With an additional imaging lenses and translational scanning, the system can be converted into a hyperspectral imager.

FOURIER SPECTROSCOPIC ANALYZER

A Fourier spectroscopic analyzer includes: a first light source that emits light including a wavelength component in a first wavelength band which is a wavelength band in which a spectrum of light passing through a sample is acquired and a wavelength component in a second wavelength band different from the first wavelength band; a second light source that emits light including the wavelength component in the second wavelength band; an interferometer that acquires an interferogram which is coherent light from the light emitted from the first light source; a first light coupling optical system that couples light emitted from the second light source to at least one of light emitted from the first light source and the interferogram acquired by the interferometer; a light receiver that outputs a first light-reception signal acquired by receiving light including the wavelength component in the first wavelength band out of the wavelength components included in the light passing through the sample and a second light-reception signal acquired by receiving light including the wavelength component in the second wavelength band; and a signal processor that performs a Fourier transform process on the first light-reception signal and the second light-reception signal to acquire a spectrum of the wavelength component in the first wavelength band with noise removed therefrom.

Spectral measurement method, spectral measurement system, and broadband pulsed light source unit
11300452 · 2022-04-12 · ·

A new spectral measurement technique is provided which enables measurement even if the light to be measured exists for a very short period. In one embodiment, a broadband pulsed light wave whose wavelength shifts temporally and continuously in a pulse interferes with a light wave to be measured. The intensity at each wavelength of the light wave to be measured is obtained using a Fourier transform of the output signal from a detector that has detected the intensity of the wave resulting from the interference. A laser beam from a laser source is converted to a supercontinuum wave by a nonlinear optical element, and a pulse extension element extends pulses of the supercontinuum wave, thus generating the broadband pulsed light wave.

TECHNOLOGIES FOR HIGH RESOLUTION AND WIDE SWATH SPECTROMETER

Technologies for a high resolution and wide swath spectrometer are disclosed. In the illustrative embodiment, an inverted image slicer converts a linear field of view into a grid shape, allowing for an interferometer of a Fourier transform spectrometer to operate on a narrow range of field of views, improving the average spectral resolution of the spectrometer.

Technologies for high resolution and wide swath spectrometer

Technologies for a high resolution and wide swath spectrometer are disclosed. In the illustrative embodiment, an inverted image slicer converts a linear field of view into a grid shape, allowing for an interferometer of a Fourier transform spectrometer to operate on a narrow range of field of views, improving the average spectral resolution of the spectrometer.

HIGH-THROUGHPUT COMPACT STATIC-FOURIER-TRANSFORM SPECTROMETER
20210310864 · 2021-10-07 ·

Systems and methods which provide a high-throughput point source light coupling structure implementing a condenser configured according to one or more condenser configuration rules are described. Embodiments of a high-throughput point source light coupling structure utilize a birefringent plate configuration in combination with a condenser and point source to provide a light coupler structure for a birefringent-static-Fourier transform interferometer implementation. According to some examples, the optical axis of a first and second birefringent plate of a birefringent plate configuration are not in the same plane. A condenser of a high-throughput point source light coupling structure of embodiments is provided in a defined (e.g., spaced, relational, etc.) relationship with respect to the point source and/or a camera lens used in capturing an interference pattern generated by the light coupling structure. High-throughput point source light coupling structures herein may be provided as external accessories for processor-based mobile devices having image capturing capabilities.

Fourier spectroscopic analyzer

A Fourier spectroscopic analyzer includes: a light receiver that receives a first wavelength component of a first wavelength band and a second wavelength component of a second wavelength band different from the first wavelength band, emits an interferogram to a sample, and outputs a first light reception signal acquired by receiving the first wavelength component and a second light reception signal acquired by receiving the second wavelength component; and a signal processing device that eliminates noise of the first wavelength component and acquires the spectrum by Fourier transform processing using the first light reception signal and the second light reception signal. The first wavelength band is a wavelength band of which a spectrum is acquired among wavelength components included in light that has passed through the sample. The interferogram is interference light and the sample is an analysis target.

Enhanced full range optical coherence tomography
11846546 · 2023-12-19 · ·

A full-range imaging method doubles imaging range of conventional techniques by removing mirror images of an imaged object that limit conventional images to a “half-range” and that are caused in part by the loss of phase information in a detected signal. Phase information of the detected signal is reconstructed with an averaging technique based on a modulated phase induced in the detected signal during scanning.

QUADRILATERAL COMMON-PATH TIME-MODULATED INTERFEROMETRIC SPECTRAL IMAGING DEVICE AND METHOD
20230408337 · 2023-12-21 · ·

The present invention belongs to the field of optical technology, disclosing a quadrilateral common-path time-modulated interferometric spectral imaging device and method. The present invention sets up a moving mirror scanning mechanism in a quadrilateral common path interferometer for generating optical path differences that vary with time, so that the quadrilateral common-path time-modulated interferometric spectral imaging device operates in the staring observation mode. The invention can make the quadrilateral common-path time-modulated interferometric spectral imaging device not only retain the advantages of common optical path spectroscopic technology, but also obtain high spectral resolution.

SYSTEMS AND METHODS FOR DUAL COMB SPECTROSCOPY

A frequency-measurement method uses a dual frequency-comb spectrometer as an optical wavemeter to measure the frequency of a reference laser that is used to frequency-stabilize the spectrometer. The method includes measuring a walking rate of center bursts in a sequence of interferograms recorded by the spectrometer, determining a number of teeth in each of a plurality of Nyquist windows formed by the dual frequency-comb spectrometer, and determining a Nyquist number of the one Nyquist window covering the laser frequency. The reference laser frequency can then be determined from the number of teeth in each Nyquist window, the Nyquist number, and the comb spacing of either one of the two frequency combs of the dual frequency-comb spectrometer. The reference laser frequency does not need to be measured with a separate wavemeter, or calibrated with respect to a known atomic or molecular transition.