4 results about "Fourier transform spectrometers" patented technology

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.

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 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.