阅读说明：本技术 光路延时双脉冲libs装置 (Light path time-delay double-pulse LIBS device ) 是由 步扬 王远航 孙晨薇 徐静浩 王向朝 于 2019-10-28 设计创作，主要内容包括：本发明公开了一种光路延时双脉冲LIBS装置。本装置采用分光镜将一台激光器射出的激光光束分成两束,其中一束光经过聚焦后直接照射在待测样品表面,另一束光先通过光路延时器延迟一定时间,再经过聚焦,最后照射在待测样品表面。通过选择反射率和透过率不同的分光镜,可以实现分光光束能量的调整。通过调整光路延时器,可以改变延时光路的光程,从而改变两束激光的光程差,实现延迟时间的改变。相较于现有的双脉冲LIBS装置,本装置只需要一台激光器,不需要数字延时脉冲发生器,降低了系统成本,缩小了系统体积,有利于双脉冲LIBS装置的集成、推广和小型化。(The invention discloses an optical path delay double-pulse LIBS device. The device adopts the spectroscope to divide a laser beam emitted by one laser into two beams, wherein one beam of light is focused and then directly irradiates the surface of a sample to be measured, and the other beam of light firstly delays for a certain time through the light path delayer, then is focused and finally irradiates the surface of the sample to be measured. The adjustment of the energy of the split beam can be realized by selecting the beam splitter with different reflectivity and transmittance. By adjusting the optical path delayer, the optical path of the delay optical path can be changed, so that the optical path difference of the two laser beams is changed, and the change of the delay time is realized. Compared with the existing double-pulse LIBS device, the device only needs one laser and does not need a digital delay pulse generator, so that the system cost is reduced, the system volume is reduced, and the integration, popularization and miniaturization of the double-pulse LIBS device are facilitated.)

1. An optical path time-delay double-pulse LIBS device comprises a pulse laser (1), a spectroscope (2), an optical path time delay device (3) with an adjustable optical path, a reflector A (4), a reflector B (5), a beam expanding collimation focusing lens group A (6), a beam expanding collimation focusing lens group B (7), a collecting lens (8), an optical fiber (9), a spectrometer (10), a computer (11) and a displacement table (12) for placing a sample (13) to be measured; the method is characterized in that:

pulse laser emitted by the pulse laser (1) is divided into transmitted light and reflected light by the spectroscope (2), wherein the reflected light is reflected by the reflector B (5) and then is focused by the beam expanding collimation focusing lens group A (6) to irradiate the surface of a sample to be measured; the transmitted light passes through the light path delayer (3), is reflected by the reflector A (4), is focused by the beam expanding collimation focusing lens group B (7), and then irradiates the surface of the sample to be measured;

two beams of laser double pulses irradiate on the surface of a sample to be detected to generate plasma, light emitted by the plasma is collected by a collecting lens (8) and transmitted to a spectrometer (10) through an optical fiber (9), and the spectrometer (10) is connected with a computer (11) and can analyze the collected spectrum;

the computer (11) controls the displacement table (12) to move the sample (13) to be measured to a specified position.

2. The optical-path time-delay double-pulse LIBS device according to claim 1, wherein: the spectroscope (2) adopts the spectroscopes with different transmissivity and reflectivity to change the proportion of the double-pulse LIBS light beam energy.

3. The optical delay double-pulse LIBS device according to claim 1, wherein the optical delay device (3) can control the delay time by adjusting the internal structure of the delay optical path, changing the optical length, and adjusting the time of the laser passing through the optical delay device.

4. The optical-path time-delay double-pulse LIBS device according to claim 1, wherein the spectrometer is provided with an external trigger module and a time delay module, and is connected with the laser device, so that the delay time between laser generation and spectrum collection can be adjusted, and the signal-to-noise ratio of the collected spectrum can be optimized.

5. The optical-path-delay double-pulse LIBS device as claimed in claim 1, wherein four modes of an orthogonal reheating type double-pulse LIBS mode, an orthogonal pre-ablation type double-pulse LIBS mode, a collinear double-pulse LIBS mode and a crossed type double-pulse LIBS mode are realized by adjusting the incidence angles of two beams of laser incident on a sample (13) to be measured and the arrangement position of the optical-path delay device.

Technical Field

The invention relates to the field of laser diagnosis and spectrum detection, in particular to a light path time-delay double-pulse Laser Induced Breakdown Spectroscopy (LIBS) device.

Background

The Laser Induced Breakdown Spectroscopy (LIBS) technology is an element component analysis technology which is developed rapidly in recent years, pulse laser with high energy and short pulse width is used as an excitation source, the pulse laser is focused and then irradiated on the surface of a sample, the sample is heated, ablated, dissociated, excited and ionized to generate plasma, and the element component and element concentration information of the sample can be obtained by analyzing the position and intensity signals of a characteristic spectral line in the plasma emission spectrum. The LIBS technology has the characteristics of high detection speed, almost no need of sample preparation, wide detection element range and capability of in-situ detection, thereby having wide application in the element detection and industrial fields.

The double-pulse Laser Induced Breakdown Spectroscopy (LIBS) technology is mainly divided into three types: collinear double-pulse LIBS techniques, orthogonal pre-ablation double-pulse LIBS techniques, and orthogonal reheat double-pulse LIBS techniques. The collinear double-pulse LIBS technology adopts two collinear pulse lasers to sequentially and vertically ablate a sample and induces the sample to generate plasma; the orthogonal pre-ablation double-pulse LIBS technology firstly adopts pulse laser parallel to the surface of a sample to puncture air near the surface of the sample, and then adopts the pulse laser vertical to the surface of the sample to ablate the sample, so that the sample generates plasma; the orthogonal reheating double-pulse LIBS technology firstly adopts pulse laser vertical to the surface of a sample to ablate the sample to generate plasma, and then adopts the pulse laser parallel to the surface of the sample to continuously heat the generated plasma. Compared with single-pulse LIBS, the double-pulse LIBS can enhance the intensity of the emission spectrum signal, improve the signal-to-noise ratio and improve the signal stability, thereby being more and more widely applied.

The traditional double-pulse LIBS system needs two lasers to generate two high-energy pulse lasers with short pulse widths, and needs a digital delay pulse generator to control the delay time between the two pulse lasers. Compared with a single-pulse LIBS system, the double-pulse LIBS system has the advantages of large size, high cost, inconvenience for integration and popularization of the double-pulse LIBS system and obstruction to miniaturization of the double-pulse LIBS system.

Disclosure of Invention

The invention aims to provide an optical path delay double-pulse LIBS device, which replaces a double laser and a digital pulse delayer by laser beam splitting and optical path delay methods and solves the problems of high cost, large volume and the like of the traditional double-pulse LIBS system.

The technical scheme adopted by the invention is as follows:

an optical path time-delay double-pulse LIBS device comprises a pulse laser, a spectroscope, an optical path time delay device with an adjustable optical path, a reflector A, a reflector B, a beam expanding and collimating focusing lens group A, a beam expanding and collimating focusing lens group B, a collecting lens, an optical fiber, a spectrometer, a computer and a displacement table for placing a sample to be measured;

pulse laser emitted by the pulse laser is divided into transmitted light and reflected light by the spectroscope, wherein the reflected light is reflected by the reflector B and then is focused by the beam expanding collimation focusing lens group A to irradiate the surface of a sample to be measured; the transmitted light passes through the light path delayer, is reflected by the reflector A, and is irradiated on the surface of a sample to be measured after being focused by the beam expanding collimating focusing lens group B;

two beams of laser double pulses irradiate the surface of a sample to be detected to generate plasma, light emitted by the plasma is collected by a collecting lens and transmitted to a spectrometer through an optical fiber, and the spectrometer is connected with a computer and can analyze the collected spectrum;

and the computer controls the displacement table to move the sample to be detected to the designated position.

In the spectroscope, laser can be divided into two beams after passing through the spectroscope, one beam is transmitted light, the other beam is reflected light, and the proportion of the energy of the double-pulse LIBS light beam can be changed by adopting the spectroscope with different transmissivity and reflectivity. .

The optical path delayer can change the optical path by adjusting the internal structure of the delay optical path, such as the length of an optical fiber, the position of a reflector and the like, and adjust the time of laser passing through the optical path delayer, thereby controlling the delay time.

The spectrometer is provided with an external trigger module and a time delay module, and is connected with the laser, so that the delay time between laser generation and spectrum collection can be adjusted, and the signal-to-noise ratio of collected spectra is optimized.

The optical path time-delay double-pulse LIBS device can realize four modes, namely an orthogonal reheating type double-pulse LIBS mode, an orthogonal pre-ablation type double-pulse LIBS mode, a collinear double-pulse LIBS mode and an intersected double-pulse LIBS mode, by adjusting the incidence angles of two beams of laser and the arrangement positions of optical path time delays.

The realization method comprises the following steps: for orthogonal double-pulse LIBS, two beams of laser can be orthogonally incident, wherein one beam is perpendicular to the surface of a sample to be measured, the other beam is parallel to the surface of the sample to be measured, if the optical path delayer is arranged in a perpendicular incident optical path, parallel light is firstly incident, the perpendicular light is incident after time delay, orthogonal pre-ablation LIBS can be realized, and if the optical path delayer is arranged in a parallel incident optical path, the perpendicular light is firstly incident, the parallel light is incident after time delay, and orthogonal reheating LIBS can be realized. For the collinear double-pulse LIBS mode, two laser beams can be collinearly vertically incident on the surface of a sample to be detected, a light path delayer is arranged in one light path, the time delay between the two laser beams is controlled, and the collinear double-pulse LIBS is realized. For the cross-type double-pulse LIBS, the angle between two beams of laser can be adjusted to enable the two beams of laser to be incident in a cross mode, the optical path delayer is installed in one beam of optical path, the time delay between the two beams of laser is controlled, and the cross-type double-pulse LIBS is achieved.

Compared with the prior art, the invention has the advantages that the number of the lasers needed by the double-pulse LIBS is reduced from two lasers to one laser by adopting a light splitting mode, the digital pulse delayer is replaced by the optical path delay, the cost and the volume of the double-pulse LIBS system are reduced, the performance of the double-pulse LIBS system is not influenced, and the popularization, the integration and the miniaturization of the double-pulse LIBS are facilitated

Drawings

FIG. 1 is a schematic structural diagram of an optical-path delay double-pulse LIBS device according to the present invention,

in the figure: 1. a pulsed laser; 2. a beam splitter; 3. an optical path delayer; 4. a reflector A; 5. a reflective mirror B; 6. a beam expanding collimation focusing lens group A; 7. a beam expanding collimation focusing lens group B; 8. a collection lens; 9. an optical fiber; 10. a spectrometer; 11. a computer; 12. a displacement table.

Detailed Description

The invention is further illustrated with reference to the following examples and figures, without thereby limiting the scope of the invention.

Referring to fig. 1, fig. 1 is a schematic structural diagram of an optical path delay double-pulse LIBS device of the present invention, and as shown in the figure, the optical path delay double-pulse LIBS detection device includes a pulse laser 1, a spectroscope 2, an optical path delayer 3, a reflective mirror A4, a reflective mirror B5, an expanded beam collimating focusing lens group A6, an expanded beam collimating focusing lens group B7, a collecting lens 8, an optical fiber 9, a spectrometer 10, a computer 11, and a displacement table 12.