Improved detection system and method of libs substance composition with high signal-to-noise ratio and low detection limit

Abstract

The invention discloses an improved material component detection system and method of LIBS with high signal-to-noise ratio and low detection limit. The system combines femtosecond pre-ablation double-pulse LIBS and polarization-resolving LIBS, including a fixed-wavelength femtosecond pulse Laser, a supercontinuum femtosecond pulse laser, a filter, a mirror placed at 45°, a beam combining mirror, a beam expander, a telescope, a beam splitter mirror placed at 45°, a polarization angle can be Adjustable polarizer, a fiber coupling mirror, a fiber interface, an ICCD spectrometer, and a computer. The system uses double pulses to excite LIBS, and the received optical signal is connected to the spectrometer through the polarizer. This system can effectively reduce the detection of elements. It can improve the signal-to-noise ratio of the signal, improve the accuracy and stability of detection, and can also detect molecular spectra and atomic spectra at the same time, providing more accurate material composition information.

Description

technical field [0001] The invention relates to a laser spectrum detection system, in particular to a combination of femtosecond Pre-Ablative Double-Pulse Laser-Induced Breakdown Spectroscopy (Femtosecond Pre-Ablative Double-Pulse Laser-Induced Breakdown Spectroscopy, referred to as fs-PA-DP-LIBS) and polarization-resolved laser-induced breakdown spectroscopy A detection system and method for Polarization Resolved Laser-Induced Breakdown Spectroscopy (PR-LIBS for short). Background technique [0002] Laser-induced breakdown spectroscopy (LIBS) detection technology uses high-energy short-pulse-width pulsed lasers to irradiate the surface of the object to be measured through focusing, and obtains laser pulses with extremely high energy density at the focus, so that the surface of the irradiated target is ablated and evaporated. , ionization, forming a plasma spark with high temperature, high pressure, and high electron density, which radiates a spectrum including characteristi...

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Problems solved by technology

[0006] In the published patent document (application number: 201210246338) of laser-induced breakdown spectroscopy measurement technology based on double-pulse and polarization resolution, reheating double-pulse LIBS is adopted, which can be used to improve detection accuracy, but reheating double-pulse LIBS The influence of impurities on the surface of the measured substance on the LIBS spectral signal cannot be removed, and it is difficult to further improve the measurement accuracy. At the same time, the traditional LIBS cannot further measure the molecular composition of the substance. In order to further improve the detection accuracy of LIBS, this patent proposes a combination Material composition detection system and detection method of femtosecond pre-ablation double-pulse LIBS and polarization-resolved LIBS, this method combines femtosecond pre-ablation double-pulse LIBS and polarization-resolved LIBS, and adjusts the time interval and polarization of double pulses through computer control The polarization angle of the plate, by changing the passband range of a specific wavelength bandpass filter, changing the wavelength of one of the laser beams, achieves the purpose of reducing the detection limit, improving detection accuracy, improving signal-to-noise ratio, and improving stability. With the application of femtosecond laser pulses, the molecular spectrum and atomic spectrum can be detected simultaneously, and more accurate material composition information can be obtained

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