CN214096364U

CN214096364U - Raman probe based on double compound eye lens set

Info

Publication number: CN214096364U
Application number: CN202120399756.3U
Authority: CN
Inventors: 黄俊杰; 蒋文波; 李潘; 卜云; 宋潇潇; 任晓; 付钱华
Original assignee: Xihua University
Current assignee: Dragon Totem Technology Hefei Co ltd; Xi'an Hengsheng Science And Technology Innovation Electromechanical Technology Co ltd
Priority date: 2021-02-23
Filing date: 2021-02-23
Publication date: 2021-08-31
Anticipated expiration: 2031-02-23

Abstract

The utility model relates to the field of optical equipment, and provides a Raman probe based on a double compound eye lens group, which comprises an excitation light path and a collection light path which are arranged vertically; the excitation light path comprises an incident light source, a beam expanding and collimating lens group, a narrow band-pass filter, a first fly-eye lens group, a concave lens and a spectroscope which are coaxial in sequence; the collecting light path comprises a long-wave pass filter, a second compound eye lens group and a collector which are coaxial in sequence, and the long-wave pass filter is positioned on one side of the spectroscope; the problem that the detection field of view of the existing Raman probe is small is solved, the lens combination structure of the first fly-eye lens group and the concave lens is adopted, and the light gathering and light equalizing properties of the fly-eye lens and the diverging properties of the concave lens are utilized, so that the output of the excitation light path is a surface rather than a point, the contact area between the excitation light path and a sample is increased, the light equalizing property and the large field area are reserved, and meanwhile, the scattered light intensity is higher.

Description

Raman probe based on double compound eye lens set

Technical Field

The utility model relates to an optical equipment field especially relates to a raman probe based on two compound eye battery of lens.

Background

The Raman probe is a key device of the Raman spectrometer and is used for transmitting an excitation beam and collecting a Raman spectrum. Since the raman scattering signal of a substance is weak, its signal intensity is about one millionth of the rayleigh scattering signal. In order to improve the detection accuracy and sensitivity of the raman probe, the raman probe needs to improve the irradiance of incident laser on one hand, and needs to reduce the rayleigh scattering signals in the collection optical path as much as possible and improve the collection efficiency of the raman signals on the other hand. Researchers at home and abroad have carried out a great deal of work and made great progress in the research of the raman probe, but the following problems still exist:

firstly, the method comprises the following steps: the detection field of view is too small. Because of the generally high spectral resolution of raman spectrometers, the spectrometers use narrow slits in the order of microns. As can be known from the conjugate relation of imaging optical object images, the field of view of the Raman probe is very small, so that the problem of over-small detection area exists. Especially when measuring heterogeneous mixtures of multiple substances, this can lead to the possibility of detecting only a single substance, which in turn can lead to measurement errors.

Secondly, the method comprises the following steps: the collection efficiency of raman spectra is not high. Since the raman scattering signal of a substance is weak, the signal intensity is about one millionth of the rayleigh scattering signal intensity. In order to improve the detection efficiency of the Raman probe, the Rayleigh scattering light entering a spectrometer is reduced on one hand, and the loss of Raman scattering signals is reduced on the other hand. A longer collection path will result in a loss of scattered signal and at the same time an increase in the volume of the whole probe; the multi-channel multi-angle collection mode is obviously not beneficial to the miniaturization of the system, and the assembly and debugging are more complex.

Thirdly, the method comprises the following steps: the detection area energy density is not high and cannot be adjusted. Because the field of view of the probe is changed from a point to a surface, the irradiance of a detection surface is reduced due to the expansion of the field of view, so that the number density of Raman scattered photons is reduced, and the detection sensitivity of the probe is insufficient. However, when detecting for example dark sensitive materials, the excessively strong irradiance of the detection surface may decompose the dark materials to cause the risk of ignition and detonation.

SUMMERY OF THE UTILITY MODEL

To the above-mentioned problem among the prior art, the utility model provides a Raman probe based on two compound eye lens groups has solved the little problem of detection visual field of present Raman probe.

In order to achieve the above object, the utility model adopts the following technical scheme:

the Raman probe based on the double compound eye lens group comprises an excitation light path and a collection light path which are perpendicular to each other;

the excitation light path comprises an incident light source, a beam expanding and collimating lens group, a narrow band-pass filter, a first fly-eye lens group, a concave lens and a spectroscope which are coaxial in sequence;

the collecting light path comprises a long-wave pass filter, a second compound eye lens group and a collector which are coaxial in sequence, and the long-wave pass filter is positioned on one side of the spectroscope.

Preferably, the incident light source is a 785nm laser with adjustable laser power.

Preferably, the normal to the beam splitter is at an angle of 45 ° to the normal to the collection path.

Preferably, the first fly-eye lens group and the second fly-eye lens group are both transmission type double-row fly-eye lenses which are parallel to each other and arranged side by side.

Preferably, the collector comprises a spectrometer connected to the focal plane of the second fly-eye lens group through a collection optical fiber.

The utility model has the advantages that:

the excitation light path adopts a lens combination structure of a first fly-eye lens group and a concave lens, and the output of the excitation light path is a surface rather than a point by utilizing the light condensation and light equalization of the fly-eye lens and the divergence property of the concave lens, so that the contact area of the excitation light path and a sample is increased, the light equalization performance and the large field area are reserved, and the scattered light intensity is higher;

the second fly-eye lens is used for replacing the traditional lens in the collection light path, so that the retention rate of Raman scattering signals after Rayleigh scattering is filtered is effectively improved, errors caused by the loss of emergent light are reduced, meanwhile, the expansion of a detection system caused by the need of a larger collection area is avoided, and the system is more miniaturized and efficient; in addition, the position of the spectroscope is changed, the collection light path is shortened, and the loss of scattered light in the collection light path is reduced.

Drawings

Fig. 1 is a schematic structural diagram of a raman probe based on a binocular lens group.

Wherein, 1, an incident light source; 2. a beam expanding and collimating lens group; 3. a narrow band pass filter; 4. a first compound eye lens group; 5. a concave lens; 6. a beam splitter; 7. a sample to be tested; 8. a long-wave pass filter; 9. a second fly-eye lens group; 10. a collector.

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and various changes may be made apparent to those skilled in the art within the spirit and scope of the present invention as defined and defined by the appended claims.

As shown in fig. 1, the present solution provides a raman probe based on a binoculus group, which includes an excitation optical path and a collection optical path that are perpendicular to each other;

the excitation light path comprises an incident light source 1, a beam expanding and collimating lens group 2, a narrow band-pass filter 3, a first fly-eye lens group 4, a concave lens 5 and a spectroscope 6 which are coaxial in sequence;

the collecting light path comprises a long-wave pass filter 8, a second compound eye lens group 9 and a collector 10 which are coaxial in sequence, and the long-wave pass filter 8 is positioned on one side of the spectroscope 6.

In the embodiment, by adopting the lens structure formed by the first fly-eye lens group 4 and the concave lens 5, compared with the traditional lens, the range of emergent light of an excitation light path is changed from a point to a surface, so that the field range is expanded; due to the characteristics of the fly-eye lens, the detection surface is uniform in illumination and higher in light irradiance; the long-wave pass filter 8 filters 785nm Rayleigh scattered light in the collection light path, and the reliability of Raman scattering signals of the collector 10 is guaranteed; the narrow band pass filter 3 filters interference signals except 785nm in the incident laser, and uniqueness of the incident laser wavelength in an excitation light path is guaranteed; the beam expanding and collimating lens assembly 2 employs a combination of a beam expanding lens and a collimating lens to ensure that light passing through the beam expanding and collimating lens assembly 2 is parallel light, and for those skilled in the art, the beam expanding and collimating lens assembly 2 is a combination of the prior art.

The focal length positions of the first fly-eye lens group 4 and the concave lens 5 are the same, so that the laser emitted by the first fly-eye lens group 4 is dispersed into parallel light through the concave lens 5, the contact area between excitation illumination and a detected sample 7 is enlarged, the uniform illumination and the large field area are reserved, and meanwhile, the scattered light intensity is higher.

The further technical scheme is as follows: the incident light source 1 is a 785nm laser whose laser power can be adjusted. The incident light source 1 capable of adjusting the laser power is adopted, only the laser intensity is changed, the laser wavelength is not changed, and the focal lengths of all components of the system are not changed, so that the detection process is more flexible; the power of the incident light source 1 can be adjusted according to requirements, so that the incident laser density in a laser light path is higher, and a Raman signal in a collected light path is stronger; when the detection substance is a dark color sensitive substance, the incident light power can be adjusted, the illumination intensity of the system is weakened, and the risks of igniting and detonating the sample are reduced.

Further improvements to this embodiment: the normal to the beam splitter 6 makes a 45 deg. angle with the normal to the collection path. The spectroscope 6 and the collection light path form an included angle of 45 degrees, 785nm laser of the excitation light path is directly transmitted to the tested sample 7, simultaneously Raman signals and Rayleigh signals scattered in the vertical direction of the tested sample 7 are reflected to the long-wave pass filter 8, 785nm Rayleigh scattered light in the collection light path is filtered, and Raman signal collection efficiency is improved.

Further improvements to this embodiment: the first fly-eye lens group 4 and the second fly-eye lens group 9 are both transmission type double-row fly-eye lenses which are parallel to each other and are arranged side by side. The structure has a converging function to incident laser.

Wherein the collector 10 comprises a spectrometer which is connected with the focus of the second fly-eye lens group 9 through a collection optical fiber.

The working process of the embodiment is as follows: the incident light source 1 is started, laser beams emitted by the incident light source 1 are collimated by the beam expanding and collimating lens group 2, and after interference waves are filtered by the narrow band-pass filter 3, the first fly-eye lens group 4 finishes focusing and homogenizing of the beams, the focused laser is dispersed into parallel light by the concave lens 5, and the parallel light irradiates the surface of a sample 7 to be measured through the spectroscope 6. The Raman scattering signal excited by the light beam of the tested sample 7 and the Rayleigh scattering signal are transmitted in reverse direction, the Rayleigh scattering light is filtered by the spectroscope 6 and the long-wave pass filter 8 in sequence, the Raman scattering light is converged by the second fly-eye lens group 9 and enters the collector 10, and finally the collector 10 is connected to the Raman spectrometer for spectral analysis.

Claims

1. A Raman probe based on a double compound eye lens group is characterized by comprising an excitation light path and a collection light path which are perpendicular to each other;

the excitation light path comprises an incident light source (1), a beam expanding and collimating lens group (2), a narrow band pass filter (3), a first fly-eye lens group (4), a concave lens (5) and a spectroscope (6) which are coaxial in sequence;

the collecting light path comprises a long-wave pass filter (8), a second compound eye lens group (9) and a collector (10) which are coaxial in sequence, and the long-wave pass filter (8) is located on one side of the spectroscope (6).

2. A raman probe based on a binocular lens set according to claim 1, characterized in that said incident light source (1) is a 785nm laser of adjustable laser power.

3. A raman probe based on a binocular lens set according to claim 1, characterized in that the normal of the beam splitter (6) is at an angle of 45 ° to the normal of the collection path.

4. A raman probe based on a set of fly-eye lenses according to claim 1, characterized in that said first set of fly-eye lenses (4) and second set of fly-eye lenses (9) are each transmissive double-row fly-eye lenses arranged parallel to each other and side by side.

5. A Raman probe based on a fly-eye lens set according to any one of claims 1 to 4, wherein the collector (10) comprises a spectrometer connected to the second fly-eye lens set (9) at the focal plane via a collection optical fiber.