Time-resolved Raman spectrometer based on super-continuum spectrum laser

Abstract

The invention discloses a time-resolved Raman spectrometer based on a super-continuum spectrum laser. The time-resolved Raman spectrometer comprises a pulse laser system, an optical beam splitting system, a signal acquisition system and a data processing system. According to the invention, a super-continuum spectrum laser is taken as a laser source, an off-chip digital delay unit is taken as time gating, a single photon avalanche diode (SPAD) array with time resolution capability is taken as a Raman signal detector, and time domain information of a Raman spectrum is recorded through an on-chip time-to-digital converter (TDC) integrated on a CMOS SPAD line sensor; a field programmable gate array (FPGA) control circuit carries out signal acquisition and processing on the CMOS SPAD line sensor, and finally data processing such as dark count removal is carried out on a computer to obtain a time-resolved Raman spectrum with high fluorescence suppression. The mode of combining the super-continuum spectrum laser and the monochromator is adopted, the to-be-detected sample is irradiated by the pulse laser with different frequencies, richer Raman spectrums and more accurate sample component information can be obtained, and the method has good use value and application prospect.

Description

technical field [0001] The invention relates to the technical field of Raman spectrometers, in particular to a time-resolved Raman spectrometer that utilizes a supercontinuum laser and a monochromator to select multi-frequency excitation light. Background technique [0002] Raman spectroscopy is widely used in the food and petroleum industries, mining, medical diagnostics, pharmaceuticals, forensics and archaeology. In many applications, the biggest challenge for Raman spectroscopy is fluorescence. Time-resolved pulsed Raman spectroscopy is ideal for fluorescence suppression because the Raman signal is acquired simultaneously with the laser pulse, and photons emitted after the laser pulse can be suppressed. Use pulsed excitation and time-gated measurements to reduce the number of detected fluorescence photons, resulting in efficient fluorescence and background suppression. Time-gated Raman spectrometers have been established based on time-gated single-photon avalanche diod...

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