Device and method for suppressing fluorescence in Raman spectrum based on dual Kerr optical switch

Abstract

The invention provides a device and method for suppressing fluorescence in a Raman spectroscopy device based on two Kerr optical switches, a laser light source, a first beam splitter, a focusing lens, a sample to be tested, a signal light converging lens, a second beam splitter, and a second beam splitter. An optical delay device, a first Kerr optical switch, a reflector, a second optical delay device, a second Kerr optical switch, a narrowband bandpass filter, and a detector. By separately controlling the delay time of the first and second optical delayers and the position of the Kerr optical switch, the filtering of interfering optical signals such as long-lived fluorescence can be achieved, so that the detector only receives The optical signal can be used to improve the signal-to-noise ratio of the Raman spectrometer, and can also be used in time-resolved spectral detection technology and devices to detect transient or ultrafast optical signals in a short time range.

Description

technical field [0001] The invention belongs to the technical field of laser spectroscopy, and in particular relates to a device and method for suppressing fluorescence noise based on a double Kerr optical switch and suitable for ultrafast Raman spectroscopy measurement. [0002] technical background [0003] Laser Raman spectroscopy is a powerful analytical technique that can be used to analyze the composition, structure and state of substances. It is widely used in detection and monitoring, analysis and characterization, etc. In material analysis, air and water environmental pollution monitoring and analysis, Food and drug analysis, product quality testing, geological exploration, marine research and national defense security and other fields have a wide range of applications. [0004] Among them, ultrafast laser Raman spectroscopy is a relatively important branch. It uses ultrafast lasers (generally referred to as picosecond or femtosecond lasers) as the excitation light s...

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Problems solved by technology

[0005] The important purpose of using ultrafast lasers in this technology is to increase the peak power density and avoid damage to the sample caused by large laser energy; however, the high peak power density laser emitted by the ultrafast laser is very easy to excite multiple Various types of nonlinear optical signals such as photon fluorescence, frequency doubling, triple frequency and multi-order Raman light lead to a decrease in the signal-to-noise ratio of the signal light to be measured, and are even completely suppressed by a variety of nonlinear background light

[0006] In Raman laser spectroscopy devices based on ultrafast lasers, frequency-doubled light, multi-frequency light, high-order Stokes light, and anti-Stokes Raman light have definite wavelengths and smaller linewidths. Therefore, it can be specifically suppressed by adding filters; however, multiphoton fluorescence can completely cover Stokes light or anti-Stokes light due to its wide band coverage, causing great interference. Difficult to filter out during testing

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