42 results about "Fourier transform spectrometers" patented technology

The present invention discloses a chip defect detection system and method based on visual recognition, and relates to the technical field of chip defect detection. The present invention comprises: S10: partitioning the surface of an epitaxial wafer, and the inner area of ​​each edge closed line in the grain boundary edge image corresponds to a partition; S20: predicting the defect index of each partition; S30: predicting the resistivity uniformity of each partition; S40: screening the epitaxial wafer with defects. The present invention partitions the surface of the epitaxial wafer to ensure that the infrared light spectrum obtained by the infrared Fourier transform spectrometer can better reflect the defect conditions of each partition, and evaluates the production quality of the epitaxial wafer through multiple physical characteristics of the epitaxial wafer in combination with the resistivity uniformity of each partition, thereby further improving the system's defect detection accuracy for the epitaxial wafer.

The invention discloses a gas detection precision improving method based on a multi-algorithm fusion framework. A photonic crystal resonant cavity and a tunable band-pass filtering structure are integrated in a Fourier transform spectrometer light path; collecting a wide-spectrum light intensity signal, and constructing a spectral signal database in combination with the enhancement characteristic and the filtering characteristic of the resonant cavity; zero calibration and dynamic baseline deduction operation are carried out, and self-adaptive variational mode decomposition and wavelet transform are adopted to carry out signal denoising on the spectral signals; an environment compensation model is established, and an Arrhenius type correction factor is adopted to suppress water vapor cross interference; constructing an RLS and fuzzy control combined hybrid adaptive filter; separating aliasing spectral signals by adopting a non-negative matrix factorization algorithm; establishing a quantitative relation model; in the online concentration prediction process, the initial concentration value is subjected to recursive optimization by using a hybrid adaptive filter, the deviation is continuously corrected through an environment compensation model, and an accurate concentration value is output. The method can significantly improve the accuracy and stability of multi-gas detection.

The invention relates to a system and a method for online detection of gas components after discharge of a high-power gas switch, and solves the technical problem that a conventional gas component detection method fails due to the fact that the gas components are gradually decomposed or compounded as time goes on after discharge of an existing high-power gas switch. The device comprises an input gas source, a flow controller, a third valve, a pressure sensor, a vacuum pump and a Fourier spectrum gas analyzer which are connected in sequence, the pressure sensor is connected with the gas switch cavity; the input gas source is specifically as follows: a helium source is connected with a flow controller through a first valve, and a zero-level air source is connected with the flow controller through a second valve; a gas outlet of the gas switch cavity is connected with the vacuum pump through a fourth valve and is connected with the Fourier spectrum gas analyzer through a fifth valve; the Fourier spectrometer is connected with the flow controller through an eighth valve; and the eighth valve is a two-position three-way valve.

A Fourier transform spectrometer including an interferometer is provided. In one embodiment, an FT spectrometer includes an excitation light source, a beam splitter adapted to separate a metrology signal from the excitation light source and direct the metrology signal through an interferometer to a metrology detector. The FT spectrometer is additionally adapted to receive a spectral signal from the sample and pass the spectral signal through the interferometer to the spectrometer detector. The invention provides a method for correcting the movement of an interferometer reflector. In addition, a total spectroscopic method is provided that includes a spectral signal that includes Raman scattering, fluorescence, and near-infrared absorption components.

The application discloses a double-waveband Fourier transform spectrometer, and relates to the technical field of spectrometers. The spectrometer comprises a first Michelson interference optical path assembly and a second Michelson interference optical path assembly. The first Michelson interference optical path and the second Michelson optical path use the front and back surfaces of a same moving mirror as phase modulators. The coating materials of the front and back surfaces of the moving mirror are different. The reflected light beams of the front and back surfaces of the moving mirror have different wavebands. The application improves the signal quality of the spectrometer when detecting wavebands or measuring across wavebands through the double-path Michelson interference optical path assembly of the shared moving mirror.

The invention discloses a Fourier transform spectrometer system of a multiband light source structure, which comprises a multiband light source conveying unit used for transmitting light of multiple bands; the collimation unit is used for collimating the light transmitted by the multiband light source conveying unit; the light beam combining unit is used for forming a combined light beam; the light splitting unit is used for respectively transmitting and reflecting the plurality of beams of light; the reflector unit is used for receiving the multiple beams of light transmitted or reflected by the light splitting unit and retroreflecting the multiple beams of light in the incident direction of the multiple beams of light; and the detection unit is used for converging the multiple beams of light reflected by the reflector unit and receiving and detecting the converged multiple beams of light. According to the invention, input wavebands can be selected and multiple wavebands can be measured simultaneously, and near-infrared light and far-infrared light can be measured simultaneously, so that the detection efficiency is improved.

The present invention provides a miniature interference spectrometer and a measurement method thereof. The spectrometer comprises a light source system, a phase modulation system, a digital micromirror array, and a detector system. The light source system is used to emit a parallel light beam, which, after distributed phase modulation by the phase modulation system, produces a light field array composed of N×N light field units. The digital micromirror array is used to select the light field array so that at least two light field units are incident on the detector system, causing interference, thereby obtaining an interference pattern signal and acquiring spectral information of the parallel light beam. The present invention avoids the high-precision manufacturing and control issues of moving mirror scanning in traditional Fourier transform spectrometers. By using a driving voltage to switch the digital micromirror units of the digital micromirror array on and off, the system eliminates the need for a beam splitting system, reduces the system's volume and weight, and improves its energy efficiency.

The application discloses an equal-wavenumber division waveband noise reduction method for an infrared Fourier transform spectrometer, and is applied to fine spectral detection with wide spectral range and ultrahigh resolution. When designing a low-temperature infrared Fourier transform spectrometer, a low-temperature filter wheel is arranged in an optical path in front of a detector, and the low-temperature filter wheel is driven by a low-temperature motor. A plurality of filters are arranged on the filter wheel, the central wavelengths of the filters are different, the central wavelength intervals are different, the central wavelengths and the bandwidths of the filters are designed according to equal central spectral intervals, each filter has a narrow bandwidth, and according to a spectral range of a required detection target, a corresponding filter is selected to realize spectral detection with ultrahigh spectral resolution of a concerned spectral range. For the infrared Fourier transform spectrometer with high spectral resolution and wide spectral bandwidth, the measurement brings the advantage of reducing noise caused by out-of-band photons on the detector, and low temperature of the filter reduces infrared background and photon noise caused by the filter body.

The invention discloses an airborne infrared spectrometer for monitoring VOCs in an oil area and a use method thereof, and relates to the technical field of VOCs gas detection.The airborne infrared spectrometer comprises an airborne platform, a spectrometer system platform is arranged on the airborne platform, and a gas pool, an active spectrometer light source and a Fourier transform spectrometer are arranged on the spectrometer system platform; the active spectrometer light source and the Fourier transform spectrometer are respectively positioned on the left side and the right side of the gas cell and are oppositely arranged; the gas tank is connected with a VOCs concentration detection assembly used for monitoring the VOCs evaporation process, and an exhaust pipe is further arranged at the top of the gas tank; the VOCs concentration detection assembly comprises an evaporation chamber and a PID detector, the evaporation chamber is mounted on the airborne platform, a VOCs liquid sample introduction pipeline is arranged at the lower part of the evaporation chamber, and the top of the evaporation chamber is connected with the gas tank through a gas inlet pipe; the PID detector is mounted at the top of the evaporation chamber; the oil area VOCs specific pollutant detection method based on Fourier infrared spectroscopy and PID detection has high efficiency, and the VOCs specific pollutants can be rapidly and accurately detected.

The present invention relates to the field of spectral imaging, and particularly to a double-step Fabry-Perot static interference Fourier transform spectrometer, which includes a light source, a collimating mirror, a Fabry-Perot array interference system, a beam reducing optical system, and a planar array detector; the light source is used to emit a light beam; the collimating mirror is used to collimate the light beam emitted by the light source into a parallel light beam; the Fabry-Perot array interference system is used to modulate the target light field into an interference light field array, which includes two stepped lenses with orthogonal step directions, and the highest steps of the two stepped lenses are closely attached, so that an air gap with a two-dimensional increment change in the shape of a checkerboard is formed between the two stepped lenses; the beam reducing optical system is used to image the interference light field modulated by the Fabry-Perot array interference system onto the planar array detector to obtain an interference image array. The present invention has the advantages of small volume, light weight, compact structure, static state, stability, reliability, etc.

The present invention provides a liquid crystal spectrometer and a measurement method thereof, wherein the spectrometer includes: a light source system, a beam splitter, a liquid crystal compensation device, a liquid crystal phase reflector, and a detector system; the light source system is used to emit a linearly polarized light beam incident on the beam splitter, which is then split into a transmitted light beam and a reflected light beam by the beam splitter. The reflected light beam is incident on the liquid crystal compensation device, reflected, and then returned to the beam splitter; the transmitted light beam is incident on the liquid crystal phase reflector, reflected, and has a preset optical path difference. It returns to the beam splitter and interferes with the reflected light beam to form an interference light beam that is incident on the detector system, thereby obtaining an interference light signal and acquiring spectral information of the linearly polarized light beam. The present invention avoids the moving mirror scanning mechanism of traditional Fourier transform spectrometers, improves the stability and reliability of the system, and reduces the volume and weight of the system. The liquid crystal spectrometer structure proposed in this invention has the characteristics of miniaturization, staticity, high stability, and high environmental adaptability.

Systems and methods for spectrometry are disclosed. In some embodiments, the system comprises a Fourier Transform Spectrometer (FTS) comprising a waveguide and a delay element. In some embodiments, the method comprises determining a power spectral density of an input optical signal via the FTS.

The invention relates to the field of spectral imaging, in particular to a low-fineness Fabry-Perot interference spatial modulation Fourier transform spectrometer, which comprises a light source, a collimating mirror, a Fabry-Perot array interference system, a beam shrinkage optical system and an area array detector, and is characterized in that the light source is used for emitting a light beam; the collimating mirror is used for collimating light beams emitted by the light source into parallel light beams; the Fabry-Perot array interference system comprises a parallel flat plate and a checkerboard step mirror, the height of steps is distributed in a checkerboard-shaped two-dimensional decreasing mode, the step height differences between every two adjacent steps are the same, the highest step is tightly attached to the parallel flat plate, and the highest step is tightly attached to the checkerboard step mirror. An air gap with the thickness changing in a two-dimensional progressive increase mode is formed between the parallel flat plate and the checkerboard step mirror, and the thickness of each area of the air gap corresponds to one optical path difference; and the beam shrinking optical system is used for imaging the modulated interference light field onto the area array detector to obtain an interference image array. The invention has the advantages of small volume, light weight, compact structure, static state, stability, reliability and the like.

Embodiments of the present disclosure relate to a technique for high resolution and wide format spectrometers. In illustrative embodiments, an inverse image slicer converts a linear field of view to a grid shape, allowing the interferometer of a Fourier transform spectrometer to operate over a narrow field of view range, thereby increasing the average spectral resolution of the spectrometer.

The invention discloses a data radiation calibration method of an interference imaging spectrometer with a four-port structure, and belongs to the technical field of Fourier transform spectrometers. According to the invention, detrending processing is carried out on black body interference data obtained from an interference imaging spectrometer interference system with a four-port structure at different temperatures; secondly, performing apodization operation on interference data by adopting a Hamming window to suppress spectrum leakage; then, performing phase correction by using an absolute value method to obtain a corresponding DN value spectrum; thirdly, comparing the temperature of the reference port with the temperature of the main optical port, correcting the direction of the response increment, and further constructing a linear equation set one by one based on the linear relation between the input increment and the response increment, and solving a radiation correction coefficient; and finally, correcting the DN value spectrum by using the radiometric calibration coefficient. By introducing a symbol resetting operation, the method effectively recovers the real increment direction of the spectral response, so that the physical interpretability and fitting stability of the calibration model are remarkably improved.

The invention relates to the field of spectral imaging, in particular to a double-step Fabry-Perot static interference Fourier transform spectrometer which comprises a light source, a collimating mirror, a Fabry-Perot array interference system, a beam shrinking optical system and an area array detector. The light source emits light beams; the collimating mirror is used for collimating light beams emitted by the light source into parallel light beams; the Fabry-Perot array interference system is used for modulating a target light field into an interference light field array, the Fabry-Perot array interference system comprises two step lenses which are orthogonal in the step direction, the highest steps of the two step lenses are tightly attached, and an air gap with the thickness changing in a checkerboard-shaped two-dimensional increasing mode is formed between the two step lenses; and the beam shrinking optical system is used for imaging the interference light field modulated by the Fabry-Perot array interference system onto the area array detector to obtain an interference image array. The invention has the advantages of small volume, light weight, compact structure, static state, stability, reliability and the like.

The application discloses a double-feedback spectrum detection method applied to a Fourier transform spectrometer, which comprises the following steps: measuring a moving mirror by using a grating ruler and obtaining a displacement A of the moving mirror, and simultaneously measuring the moving mirror by using a laser and obtaining a displacement A of the moving mirror; judging whether the difference between the displacement A and the displacement A is less than an error threshold value; if the difference is less than the error threshold value, outputting the displacement A; and if the difference is greater than or equal to the error threshold value, outputting the displacement A and determining that the laser measurement is abnormal. The grating ruler is arranged to perform supplementary measurement, and the measurement result is compared with the result measured by the laser in real time, so that the error measurement data of the laser can be found in time and replaced, thereby ensuring that the result of the displacement of the moving mirror is always correct, and the reliability of the measurement result is improved, and the damage of the moving mirror to the measuring instrument caused by the error movement of the moving mirror due to the output of the error data parameter is avoided.

The present invention provides a liquid crystal spatial light modulation spectrometer and a measurement method thereof, wherein the spectrometer includes: a light source system, a liquid crystal phase control array, a liquid crystal optical switch array, and a detector system; the light source system is used to emit a linearly polarized light beam incident on the liquid crystal phase control array, and the linearly polarized light beam is transmitted through the liquid crystal phase control array to obtain a light field array with a preset optical path difference; the liquid crystal optical switch array is used to select the light field array, so that the light beams corresponding to at least two different light field units in the light field array are incident on the detector system to interfere to form an interference light beam, obtain an interference pattern sequence, and obtain the spectral information of the linearly polarized light beam. The present invention avoids the moving mirror scanning mechanism and beam splitting system of the traditional Fourier transform spectrometer, reduces the volume and weight of the system, and improves energy utilization. The micro-spectrometer structure proposed by the invention has the characteristics of miniaturization, lightweight, and high energy utilization.

The invention provides a Fourier transform spectrometer synchronous data acquisition device and a control method thereof, and the device comprises an interference signal conditioning module which is used for carrying out the synchronous amplification of a plurality of interference signals, and obtaining an amplified multi-source interference signal; the clock management module is used for performing fan-out buffering on the adjustable sampling clock signal to obtain a multi-channel ADC sampling clock signal; the multi-channel ADC sampling module is used for synchronously sampling the amplified multi-source interference signal according to a multi-channel ADC sampling clock signal to obtain multi-channel interference signal sampling data; and the master control FPGA module is used for caching the multi-channel interference signal sampling data and sequentially performing adaptive filtering, zero crossing point detection, difference reconstruction, timestamp addition and data framing processing on the multi-channel interference signal sampling data to obtain framed interference data. According to the device, the reliability of data acquisition of the multi-channel Fourier transform spectrometer is improved.

The present invention provides a spatial light modulation spectrometer and a measurement method thereof, comprising: a light source system, a liquid crystal phase modulation array, a digital micromirror array, and a detector system; the light source system is used to emit a linearly polarized light beam, and after distributed phase modulation by the phase modulation array, a light field array composed of M×M light field units is obtained; the digital micromirror array is used to gate the light field array, so that the light beams corresponding to at least two light field units are incident on the detector system to generate interference, and an interference pattern signal is obtained to acquire the spectral information of the linearly polarized light beam. The present invention realizes the precise modulation of the optical path difference and the precise sampling of the interference signal. This invention patent proposes a Fourier transform spectrometer based on a liquid crystal phase modulation array and a digital micromirror array for precise scanning without optical path difference and energy splitting, avoiding the difficulties in the fabrication and control of the scanning moving mirror, reducing the volume and weight of the system, and at the same time improving the energy utilization rate of the system.

The present invention discloses an equivalent wavelength phase stabilization system for Fourier ultrafast spectroscopy, including a laser generation module, a Mach-Zehnder interference optical path module, and an interference phase measurement and real-time conversion module. Based on Fourier ultrafast spectroscopy technology, the present invention measures and converts the reference light interference phase in real time, circumvents the wavelength dependence limitation of phase stability, achieves wavelength-independent phase stabilization, and thus overcomes the limitation of the single working wavelength of Fourier ultrafast spectroscopy, broadens the application band range of Fourier spectroscopy technology, and reduces the influence of environmental disturbances on the phase stability of the spectrometer, thereby improving the Fourier spectrum signal-to-noise ratio. In addition, the method of the present invention only adds modules such as phase modulation and phase conversion to the original Fourier transform spectrometer, the experimental device is simple, and the present invention can be extended to the field of two-dimensional and even multi-dimensional Fourier ultrafast spectroscopy.

The present invention relates to a Fourier transform spectrometer applicable in an array of coherent light sources, comprising: a light source, a light transmission device, a control circuit, a detector, an amplifying circuit, and a computer. The control circuit is electrically connected to the light transmission device for control the on-off of light in the light transmission device. The amplifying circuit is connected with the detector for recording and amplifying the photoelectric signal obtained by the detector. The computer is connected with the amplifying circuit. The computer is equipped with a spectral analysis software is used to perform Fourier transform. The Fourier transform spectrometer based on the coherent light source array further includes a coherent light source array. The light transmission device is used to transmit the light emitted by the light source to the coherent light source array.

A real-time measurement method and apparatus for long-wave infrared pulse spectra based on nonlinear frequency upconversion is disclosed. The method utilizes a non-oxide semiconductor crystal as the nonlinear medium and employs a narrowband pulse with a center wavelength in the range of 2-2.5 μm as the sampling light. This pulse is summed with the long-wave infrared pulse to be measured, and the resulting summed pulse is received and detected by a near-infrared real-time spectrometer. The combination of the selected sampling light wavelength and the selected crystal generates an ultra-wide phase-matching bandwidth. Through a linear frequency mapping relationship, the spectrum of the long-wave infrared pulse to be measured can be inverted from the detected summed pulse spectrum. By analyzing the spectrum acquired by the near-infrared spectrometer in real time, the spectrum of the long-wave infrared pulse to be measured can be directly and in real-time reconstructed. This invention overcomes the limitations of Fourier transform spectrometers and traditional grating spectrometers in real-time measurement, achieving real-time, mechanical-scan-free measurement of long-wave infrared pulse spectra without requiring a specific repetition frequency for the long-wave infrared pulse.

A Fourier transform spectrometer 100 includes an interferometer 10, which includes a fixed mirror 11, a movable mirror 12, and a detector 101, wherein: the mirrors 11 and 12 are positioned parallel to each other and form an optical cavity; the movable mirror 12 is operable to move relative to the fixed mirror 11 to change the size of the optical cavity; a first mirror in the mirrors is positioned such that light 14 received from a sample passes through the back of the first mirror into the optical cavity; the detector 101 is positioned and operable to detect light that has passed through the back of a second mirror in the mirrors and exits the optical cavity and outputs an interferogram; and the mirrors 11 and 12 are spaced apart from each other such that the movable mirror is positioned or can be moved to a position in which at least two paths 16, 31 of the received light 14 reflected within the interferometer toward the detector 101 have equal lengths.

The present invention provides a phase-modulation array liquid crystal spectrometer and a measurement method thereof, wherein the spectrometer comprises: a light source system, a phase modulation system, and a detector system; the phase modulation system comprises: a beam splitter, a row-oriented liquid crystal phase modulation array, and a column-oriented liquid crystal phase modulation array; the light source system is configured to emit a linearly polarized light beam, which is incident on the beam splitter and split into a reflected light beam and a transmitted light beam. The reflected light beam and the transmitted light beam are respectively incident on the row-oriented liquid crystal phase modulation array and the column-oriented liquid crystal phase modulation array, where they are reflected again to produce a preset optical path difference. The reflected light beam and the transmitted light beam return to the beam splitter, where they are superimposed and interfere with each other to produce an interference light beam; the interference light beam is incident on the detector system to obtain an interference image sequence, thereby acquiring spectral information of the linearly polarized light beam. The present invention solves the problems of low reliability, large size and weight, and poor real-time performance caused by mechanical scanning of moving mirror scanning Fourier transform spectrometers.

A beam splitter is used for receiving a collimated light source and emitting a reflected light beam and a transmitted light beam, and the reflected light beam and the transmitted light beam return to the beam splitter to be recombined after being reflected by a plane mirror and are received by a detector through an imaging lens; wherein the plane mirrors comprise a first mirror and a third mirror which are parallel to each other and form a pair, and a second mirror and a fourth mirror which are parallel to each other and form a pair, and the two pairs of mirrors are respectively fixed on corresponding movable arms and are driven by the respective movable arms to rotate around a rotating shaft; the rotating shaft is located at the axisymmetric center of the second reflector and the fourth reflector. Compared with a Michelson interferometer, the interferometer has the advantages that the problem caused by inclination of the moving mirror is greatly reduced when the interferometer is applied to the Fourier transform spectrometer, and meanwhile, a large optical path difference is obtained in a small rotation angle.

The invention discloses a mode multiplexing MZI-based on-chip Fourier transform spectrometer, which comprises an MZI, a detector and a Fourier transform module, and is characterized in that to-be-detected light is input through the input end of the MZI, and the output end of the MZI is sequentially connected with the detector and the Fourier transform module. The MZI based on mode multiplexing enables the transmission modes TE0, TE1 and TE2 in the two arms to be modulated respectively, and meanwhile, the modulation electrode of the push-pull structure enables the modulated modes in the upper arm and the lower arm to generate opposite and large effective refractive index changes, so that the effective optical path difference of the two arms is greatly increased, and the transmission efficiency of the two arms is improved. Therefore, the on-chip Fourier transform spectrometer which is high in resolution, low in power consumption and simple and compact in structure is achieved, and the MZI structure with the two folded arms is simple and compact.

The present invention discloses an on-chip Fourier transform spectrometer based on a mode-multiplexing MZI, comprising an MZI, a detector, and a Fourier transform module. Light to be measured is input through the MZI input, and the MZI output is sequentially connected to the detector and the Fourier transform module. The mode-multiplexing MZI of the present invention modulates the transmission modes TE0, TE1, and TE2 in the two arms, respectively. Simultaneously, a push-pull modulation electrode causes the modulated modes in the upper and lower arms to produce opposite, larger effective refractive index changes, thereby greatly increasing the effective optical path difference between the two arms. This results in a high-resolution, low-power, simple, and compact on-chip Fourier transform spectrometer. Furthermore, the MZI of the present invention, with its two-arm folding design, is simple and compact.

The application discloses a Fourier transform spectrometer based on a multi-channel waveguide, which comprises a grating coupler, wherein probe light is coupled into a waveguide structure through the grating coupler after passing through a measured sample, the waveguide structure comprises a multiple beamsplitter, an active Mach-Zehnder interferometer array and a high-speed photodetector array; the multiple beamsplitter is used for splitting the incident probe light and then the split light is incident into the active Mach-Zehnder interferometer array, each channel of the multiple beamsplitter corresponds to a group of active Mach-Zehnder interferometers; each channel of the active Mach-Zehnder interferometer array is connected with the high-speed photodetector array through a transmission waveguide. The application has the advantages that the mature Mach-Zehnder interferometer technology is used to reduce the process complexity of the existing Fourier spectrometer structure and improve the process consistency.

The present invention relates to the field of spectral imaging, and particularly to a Fabry-Perot interferometric spatial modulation Fourier transform spectrometer with low finesse, which includes a light source, a collimating mirror, a Fabry-Perot array interferometric system, a beam-reducing optical system, and a planar array detector. The light source is used to emit a light beam; the collimating mirror is used to collimate the light beam emitted by the light source into a parallel light beam; the Fabry-Perot array interferometric system includes a parallel flat plate and a checkerboard stepped mirror, the step heights are distributed in a two-dimensional decreasing manner in a checkerboard pattern, the step height differences between adjacent two steps are the same, the highest step is closely attached to the parallel flat plate, and an air gap with a two-dimensional increasing thickness change is formed between the parallel flat plate and the checkerboard stepped mirror, and the thickness of each region of the air gap corresponds to an optical path difference respectively; the beam-reducing optical system is used to image the modulated interference light field onto the planar array detector to obtain an interference image array. The present invention has the advantages of small volume, light weight, compact structure, static state, stability, reliability, etc.