Device and method for inhibiting fluorescence in Raman spectrum based on double Kerr optical switches

Abstract

The invention provides a device and a method for inhibiting fluorescence in a Raman spectrum device based on double Kerr optical switches. The device comprises a laser light source, a first spectroscope, a focusing lens, a to-be-tested sample, a signal light convergence lens, a second spectroscope, a first light delayer, a first Kerr optical switch, a reflector, a second light delayer, a second Kerr optical switch, a narrow-band band-pass filter, and a detector. Interference optical signals such as long-life fluorescence can be filtered by respectively controlling the delay time of the first optical delayer and the second optical delayer and the position of the Kerr optical switch, so that the detector only receives optical signals within a specific pulse width or time period to increase the signal-to-noise ratio of the Raman spectrometer, and also can also be used for detecting transient or ultrafast optical signals in a short time range in a time-resolved spectrum detection technology and a time-resolved spectrum detection device.

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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