Single-pulse laser-induced transient molecular fluorescence spectrum measurement method and system

Abstract

The invention provides a single-pulse laser-induced transient molecular fluorescence spectrum measurement method and system, and the method comprises the steps: employing a femtosecond laser-induced fluorescence emission technology to excite a sample to generate to-be-measured fluorescence, and enabling the fluorescence to be collected in a reverse direction in the propagation direction of excitation light; enabling one linear chirped pulse to interact with a fluorescence signal to be detected in a second-order nonlinear medium to generate a sum frequency optical signal, wherein an intensity recess is formed in the acted chirped pulse, and the chirped pulse with the intensity recess is subjected to time broadening through a time amplification system; detecting the broadened chirped pulse with the recess and the component of the linear chirped pulse by a photoelectric detector with high-speed response together, outputting, recording and measuring two signals by a high-speed oscilloscope, and obtaining a transient molecular fluorescence signal spectrum after time amplification after processing. According to the technology, a molecular fluorescence spectrum excited by a single femtosecond pulse can be rapidly measured, a continuous single-frame fluorescence signal spectrum with high resolution and real-time performance is obtained, and the method is a method for rapidly measuringthe spectrum aiming at an irrepeatable physical process or an irreversible transient process.

Description

technical field [0001] The invention relates to the field of ultrafast laser and laser spectrum measurement, in particular to ultrafast femtosecond optics, physics of interaction between light and matter, and nonlinear spectrum technology. Background technique [0002] Laser-induced fluorescence spectroscopy refers to the use of laser light to excite the electrons of molecules / atoms to transition to a high energy level state, and to measure the fluorescence signal radiated by the electronic energy level back transition. Since the molecular fluorescence spectrum has nothing to do with the wavelength of the excitation light source, it is only related to the energy level structure of the fluorescent substance itself, so the qualitative (or quantitative) analysis and identification of fluorescent substances can be carried out according to the fluorescent spectral lines. Because the collection and detection direction of laser-induced fluorescence is different from that of excitat...

AI Technical Summary

Problems solved by technology

However, molecular fluorescence signals are incoherent light, which cannot exhibit frequency characteristics through time stretching, so this technique cannot be directly applied to the measurement of molecular fluorescence spectra

[0007] In summary, although laser-induced molecular fluorescence measurement provides important research and measurement methods for the fields of spectral remote sensing and nonlinear photophysics, the technology is still limited in terms of high time resolution and measurement of molecular transient processes. There are more or less technical deficiencies and defects

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