CN103411932A

CN103411932A - LIBS testing system and method based on remote zoom optical multiplexing

Info

Publication number: CN103411932A
Application number: CN2013103270578A
Authority: CN
Inventors: 万雄; 舒嵘; 王建宇; 亓洪兴
Original assignee: Shanghai Institute of Technical Physics of CAS
Current assignee: Shanghai Institute of Technical Physics of CAS
Priority date: 2013-07-30
Filing date: 2013-07-30
Publication date: 2013-11-27
Anticipated expiration: 2033-07-30
Also published as: CN103411932B

Abstract

The invention discloses a LIBS (Laser-induced Breakdown Spectroscopy) testing system and method based on the remote zoom optical multiplexing. The system mainly comprises a remote zoom optical multiplexing LIBS telescope, which consists of a beam expander, a beam splitter placed at 45 degrees, an adjusting mirror set, a secondary beam expanding and focusing mirror set, an adjustable fiber coupling mirror and a fiber interface. The method provided by the invention can realize optical multiplexing in LIBS excitation and LIBS spectrum signal acquisition; due to the coating design, efficient transmission of 1064 nm pulse laser and efficient acquisition of LIBS spectrum signals within the range of 200 nm-750 nm are realized, and the remote LIBS signal-to-noise ratio is increased.

Description

LIBS test macro and method of testing based on long-range zoom path multiplexing

Technical field

This patent relates to a kind of laser spectrum detection method, relates in particular to a kind of Laser-induced Breakdown Spectroscopy based on long-range zoom path multiplexing (Laser-induced breakdown spectroscopy is called for short LIBS) detection method.

Background technology

Remote laser induced breakdown spectroscopy (LIBS) Detection Techniques are the pulse lasers that utilize high-energy, short pulse duration, low recurrent frequency pulse laser device to send, through condenser lens, focus on long-range target surface, on focus point, obtain the laser pulse of instantaneous high power density, can make the ablation of target surface focus point, evaporation and ionization form the plasma spark of high temperature, high pressure, high electron density, give off the spectrum that comprises atom and ion characteristic spectral line, the element that can be used for detecting material forms.

Long-range LIBS Detection Techniques need to solve two major issues: the first, and because detection range is far away, pulse laser has larger energy attenuation after each optics of system, how to guarantee that the high efficiency of transmission of laser energy is extremely important.Second, because the optics bore of detection system is very little corresponding to the space multistory angle of remote object surface focus point, cause the LIBS signal gathered by the possible detection system that the target surface focus point sends very faint, therefore need to effectively improve the collecting efficiency of long-range LIBS signal.

For the transfer efficiency that improves long-range LIBS direct impulse laser and the collecting efficiency of LIBS signal, the long-range LIBS of final raising surveys signal to noise ratio (S/N ratio), this patent proposes a kind of detection method of LIBS based on long-range zoom path multiplexing, the method can realize that LIBS excites the path multiplexing gathered with the LIBS spectral signal, thereby the heavy-caliber optical system that utilizes the focus lamp group carries out the collection of LIBS echoed signal, increased the space multistory angle of collection signal, and the design due to plated film, realized the efficient highly effective gathering that sees through the LIBS spectral signal that reaches the 200nm-750nm scope for the 1064nm pulse laser, improved the signal to noise ratio (S/N ratio) of long-range LIBS.

Summary of the invention

The purpose of this patent is to provide a kind of detection method of LIBS based on long-range zoom path multiplexing, utilizes the heavy-caliber optical system of focus lamp group to carry out the collection of LIBS echoed signal, has increased the space multistory angle of collection signal.Utilize the design of optical system plated film, realized the efficient highly effective gathering that sees through the LIBS spectral signal that reaches the 200nm-750nm scope for the 1064nm pulse laser, improved the signal to noise ratio (S/N ratio) of long-range LIBS.

This patent is achieved like this, and its method step is:

By the psec solid pulse laser, send the picosecond pulsed laser that a branch of wavelength is 1064nm, expand by the beam expander that is coated with the 1064nm high transmittance film, see through and become 45 with optical axis ⁰The beam splitter that is coated with 1064nm high transmittance film and 200nm-750nm high-reflecting film of installing, see through again the adjustment mirror group that is coated with 1064nm and 200nm-750nm high transmittance film, through the secondary that is coated with 1064nm and 200nm-750nm high transmittance film, expand the focus lamp group again and expand and focus on, converge to distant object more lip-deep.In this excitation process, pulse laser each optical element of process be coated with the 1064nm high transmittance film, thereby guaranteed the high efficiency of transmission of laser, improved transmitance, effectively reduced optical energy loss.

The LIBS flashlight gone out from the remote object surface excitation mainly concentrates on the 200nm-750nm spectral range; at first this flashlight oppositely expands the focus lamp group through the secondary that is coated with 1064nm and 200nm-750nm high transmittance film and realizes path multiplexing; because the focus lamp group belongs to optical elements of large caliber, therefore improved the solid angle that flashlight gathers; Then see through the adjustment mirror group that is coated with 1064nm and 200nm-750nm high transmittance film, again through being coated with the beam splitter reflection of 1064nm high transmittance film and 200nm-750nm high-reflecting film, finally by the adjustable optic fibre coupling mirror that excessively is coated with the 200nm-750nm high transmittance film, focus to the fiber end face of the ICCD spectrometer that is inserted in optical fiber interface, then by the ICCD spectrometer, gather and analyze the LIBS spectral signal.By regulating the adjustable optic fibre coupling mirror, can make the LIBS flashlight accurately gather fiber end face.In this signal acquisition process, all optical elements that the LIBS flashlight passes through all are coated with 200nm-750nm high transmittance film or high-reflecting film, thereby can effectively reduce the loss of flashlight, improve the collecting efficiency of flashlight.

Because remote object is unfixing from the detection system distance, the maneuverability of surveying for improving long-range LIBS, can adjust the distance that mirror group and secondary expand the focus lamp group by adjusting and change the focal length of light path system, thereby realize zoom function, the LIBS that can be used for the different distance target surveys.

The method has realized that LIBS excites the path multiplexing gathered with the LIBS spectral signal, and the design due to plated film, realize the efficient highly effective gathering that sees through the LIBS spectral signal that reaches the 200nm-750nm scope for the 1064nm pulse laser, improved the signal to noise ratio (S/N ratio) of long-range LIBS.

The accompanying drawing explanation

Fig. 1 is the schematic diagram of this patent, in figure: 1---and the psec solid pulse laser; 2---long-range zoom path multiplexing LIBS telescope; 3---beam expander; 4---beam splitter; 5---adjust the mirror group; 6---zoom controller; 7---secondary expands the focus lamp group; 8---remote object; 9---the ICCD spectrometer; 10---optical fiber; 11---optical fiber interface; 12---the adjustable optic fibre coupling mirror.

Embodiment

The principle of this patent as shown in Figure 1, comprises psec solid pulse laser 1, long-range zoom path multiplexing LIBS telescope 2, optical fiber 10 and ICCD spectrometer 9 based on the LIBS test macro of long-range zoom path multiplexing.Its medium-long range zoom path multiplexing LIBS telescope 2 is expanded focus lamp group 7, adjustable optic fibre coupling mirror 12 and optical fiber interface 11 and is formed by beam expander 3, beam splitter 4, adjustment mirror group 5, zoom controller 6, secondary

By psec solid pulse laser 1, send the picosecond pulsed laser that a branch of wavelength is 1064nm, expand by the beam expander 3 that is coated with the 1064nm high transmittance film, see through and become 45 with optical axis ⁰The beam splitter 4 that is coated with 1064nm high transmittance film and 200nm-750nm high-reflecting film of installing, see through again the adjustment mirror group 5 that is coated with 1064nm and 200nm-750nm high transmittance film, through the secondary that is coated with 1064nm and 200nm-750nm high transmittance film, expand focus lamp group 7 again and expand and focus on, converge to remote object 8 more lip-deep.In this excitation process, pulse laser each optical element of process be coated with the 1064nm high transmittance film, thereby guaranteed the high efficiency of transmission of laser, improved transmitance, effectively reduced optical energy loss.Thereby by zoom controller 6, can regulate and adjust the focal length that distance that mirror group 5 and secondary expand focus lamp group 7 changes light path system, realize zoom function, the LIBS that can be used for the different distance target surveys.

The LIBS flashlight gone out from the remote object surface excitation mainly concentrates on the 200nm-750nm spectral range; at first this flashlight oppositely expands focus lamp group 7 through the secondary that is coated with 1064nm and 200nm-750nm high transmittance film and realizes path multiplexing; because the focus lamp group belongs to optical elements of large caliber, therefore improved the solid angle that flashlight gathers; Then see through the adjustment mirror group 5 that is coated with 1064nm and 200nm-750nm high transmittance film, beam splitter 4 reflections through being coated with 1064nm high transmittance film and 200nm-750nm high-reflecting film again, finally by crossing the adjustable optic fibre coupling mirror 12 be coated with the 200nm-750nm high transmittance film, focus on the end face of the optical fiber 10 that the ICCD spectrometer 9 that is inserted in optical fiber interface 11 joins, then by ICCD spectrometer 9, gather and analyze the LIBS spectral signal.By regulating adjustable optic fibre coupling mirror 12, can make the LIBS flashlight accurately gather the end face of optical fiber 10.In this signal acquisition process, all optical elements that the LIBS flashlight passes through all are coated with 200nm-750nm high transmittance film or high-reflecting film, thereby can effectively reduce the loss of flashlight, improve the collecting efficiency of flashlight.

Because excitation light path and signals collecting light path have realized multiplexingly, and the long-range zoom path multiplexing LIBS telescope 2 of all being integrally formed of optical element enclosed constructions, can effectively overcome the impact of extraneous parasitic light, thereby further improve signal to noise ratio (S/N ratio).

Claims

1. test macro of the Laser-induced Breakdown Spectroscopy based on long-range zoom path multiplexing, it comprises psec solid pulse laser (1), long-range zoom path multiplexing LIBS telescope (2), ICCD spectrometer (9), optical fiber (10), optical fiber interface (11) and adjustable optic fibre coupling mirror (12), it is characterized in that: described test macro adopts a long-range zoom path multiplexing LIBS telescope, this telescope is by a beam expander, the beam splitter of 45 ° of placements, adjust the mirror group for one, a secondary expands the focus lamp group, an adjustable optic fibre coupling mirror and an optical fiber interface form, wherein said beam expander is coated with the 1064nm high transmittance film, described beam splitter is coated with 1064nm high transmittance film and 200nm-750nm high-reflecting film, described adjustment mirror group and secondary expand the focus lamp group and are coated with 1064nm and 200nm-750nm high transmittance film, described adjustable optic fibre coupling mirror is coated with the 200nm-750nm high transmittance film.

2. method of testing of the LIBS based on the described test macro of claim 1, it is characterized in that: wavelength 1064nm pulse laser is successively by being coated with the beam expander of 1064nm high transmittance film, be coated with the beam splitter of 1064nm high transmittance film and 200nm-750nm high-reflecting film, be coated with the adjustment mirror group of 1064nm and 200nm-750nm high transmittance film, the secondary that is coated with 1064nm and 200nm-750nm high transmittance film expands the focus lamp group, then focus on distant object more lip-deep, the LIBS spectral signal inspired oppositely expands the focus lamp group through the secondary that is coated with 1064nm and 200nm-750nm high transmittance film successively, be coated with the adjustment mirror group of 1064nm and 200nm-750nm high transmittance film, then through being coated with the beam splitter reflection of 1064nm high transmittance film and 200nm-750nm high-reflecting film, through the adjustable optic fibre coupling mirror that is coated with the 200nm-750nm high transmittance film, focus to again the fiber end face of the ICCD spectrometer that is inserted in optical fiber interface, then by the ICCD spectrometer, gather and analyze the LIBS spectral signal.