Device for improving collection efficiency of monochromatic fluorescent photons
By installing a concave mirror at the lower end of the target cavity and setting a notch filter at the entrance of the collection barrel, the dispersion and stray light influence of the photomultiplier tube when detecting fluorescent photons is solved, and the collection efficiency and detection accuracy of fluorescent photons are improved.
Patent Information
- Application Number
- CN202421803992.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-29
- Publication Date
- 2025-06-06
- Estimated Expiration
- 2034-07-29
AI Technical Summary
In the prior art, when detecting fluorescent photons, the photomultiplier tube is affected by the decrease in the number of dispersed fluorescent photons emitted by the target cavity and the scattered and stray light of the incident light, resulting in a decrease in the accuracy of the detection result.
A device is designed including a concave mirror at the lower end of the target cavity to collect and reflect dispersed fluorescent photons and a notch filter at the entrance of the collection barrel to filter fluorescent photons of a specific wavelength and to reduce the influence of scattered and stray light.
By increasing the collection efficiency of fluorescent photons, the detection accuracy of the photomultiplier tube on fluorescent photons is improved, and the signal-to-noise ratio of the two-photon absorption spectrum is improved.
Smart Images
Figure CN222952197U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of optics, in particular to a device for increasing the collection efficiency of monochromatic fluorescent photons. Background Art
[0002] Two-photon absorption is the process in which a medium absorbs two photons, in which each individual photon does not have enough energy to excite the molecules (in the medium) to an excited state. Instead, the two photons work together to reach the excited state from the ground state through a virtual state. This process absorbs a total of two photons, hence the name two-photon absorption.
[0003] In the prior art, in the entire two-photon absorption optical path, the incident laser beam emitted by the front-end laser reaches and passes through the target cavity, then is reflected by the reflector to form a reflected laser beam and returns along the original optical path. The heated target atomic vapor in the target cavity first absorbs a beam of photon energy and transitions to the intermediate metastable structure, and then reversely absorbs a beam of photons from the direction of the rear-end reflector. The extranuclear electrons of the metastable structure further transition to a higher level of excited state, and then de-excite to the ground state. In this process, fluorescent photons of a specific wavelength are emitted, laying the foundation for the subsequent PMT (photomultiplier tube) to detect the two-photon absorption spectrum.
[0004] However, when the photomultiplier tube of the prior art detects fluorescent photons, on the one hand, the fluorescent photons emitted by the target cavity are relatively scattered, thereby reducing the number of fluorescent photons reaching the photomultiplier tube; on the other hand, during actual detection, not only fluorescent photons, but also some scattered light of the incident light and external stray light are easily detected by the photomultiplier tube, which in turn affects the accuracy of the photomultiplier tube's detection results of fluorescent photons. Utility Model Content
[0005] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the utility model is: how to provide a device that can gather the fluorescent photons emitted by the target cavity as much as possible so that they can be better detected by the photomultiplier tube, while also reducing the influence of scattered light and stray light of the incident light and increasing the collection efficiency of monochromatic fluorescent photons.
[0006] In order to solve the above technical problems, the utility model adopts the following technical solutions:
[0007] A device for increasing the collection efficiency of monochromatic fluorescent photons comprises a shell, a side of the shell is provided with an incident port for incident laser to pass through, a target cavity, a reflecting mirror and a concave mirror are arranged in the shell, a collecting cylinder connected to the inside of the shell is also arranged on the top surface of the shell, a notch filter is arranged near the entrance of the shell, a photomultiplier tube is installed on the upper end of the collecting cylinder, the concave mirror is located below the target cavity, the collecting cylinder, the target cavity and the concave mirror are located in corresponding positions in the vertical direction, the opening of the concave mirror faces the direction of the collecting cylinder, and the focus of the concave mirror is located between the notch filter and the photomultiplier tube.
[0008] In this way, when the device of this scheme is in use, the incident laser generated by the laser enters the outer shell through the incident port, the incident laser entering the outer shell further enters the target material cavity, the incident laser entering the target material cavity is absorbed by the target material atomic vapor in the target material cavity, and transitions to a metastable structure, and then the incident laser further passes through the target material cavity and is emitted from its rear end and hits the reflector, the reflector reflects the incident laser to form a reflected laser and enters the target material cavity again, the reflected laser entering the target material cavity is secondarily absorbed by the target material atomic vapor, and the electrons outside the nuclei in the metastable structure are excited to a better energy state, and when the excited electrons de-excite to the ground state, fluorescent photons of a specific wavelength are emitted, and the fluorescent photons are collected in the target material cavity and converged into the collecting tube, and the fluorescent photons converged in the collecting tube are further absorbed by the photomultiplier tube, thereby achieving the purpose of experimental measurement of two-photon absorption.
[0009] In the process of collecting fluorescent photons, the present invention arranges a concave mirror at the lower end of the target cavity, and at the same time directs the opening of the concave mirror toward the direction of the collecting tube. The collecting tube, the target cavity and the concave mirror correspond to each other in the vertical direction, and the focus of the concave mirror is located between the notch filter and the photomultiplier tube. Since the fluorescent photons emitted by the target cavity are emitted at an angle of 4π, the concave mirror is arranged at the lower end of the target cavity. The concave mirror can reflect as many fluorescent photons dispersedly emitted by the target cavity as possible toward the direction of the collecting tube, thereby greatly increasing the number of fluorescent photons reaching the collecting tube, and further allowing more fluorescent photons to be detected by the photomultiplier tube. At the same time, By installing a notch filter at the entrance of the collecting tube, the notch filter can only allow fluorescent photons of a specific wavelength to pass through, while photons of other wavelengths are reflected. Since the light converged at the collecting tube includes not only fluorescent photons but also some scattered light of the incident light and some stray light from the outside, by setting the notch filter, as many fluorescent photons as possible that need to be collected can pass through the notch filter and reach the photomultiplier tube to be absorbed, while the scattered light and stray light of the incident light can be reflected as much as possible, thereby reducing the influence of the scattered light and stray light of the incident light, further improving the signal-to-noise ratio of the two-photon absorption spectrum, and ensuring the accuracy of the fluorescence photon detection results of the photomultiplier tube.
[0010] Preferably, the inner wall of the collecting tube is coated with a reflective layer made of reflective material.
[0011] In this way, by coating the inner wall of the collecting tube behind the notch filter with reflective material to form a reflective layer, the fluorescent photons reaching the notch filter can be received by the photomultiplier tube sealed and installed in the collecting tube as much as possible after multiple reflections.
[0012] Preferably, the notch filter is movably connected to the inlet of the collecting cylinder.
[0013] Preferably, the width of the concave mirror along the axial direction is greater than the width of the target cavity and the collecting tube along the axial direction.
[0014] In this way, the fluorescent photons emitted from different positions of the target cavity can be reflected by the concave mirror as much as possible.
[0015] Preferably, the two axial ends of the concave mirror are respectively connected to the focal position of the concave mirror, and the angle formed by the two connecting lines is not less than 45°.
[0016] In this way, since the fluorescent photons in the target cavity are emitted at an angle of 4π, the angle formed by the lines connecting the two axial ends of the concave mirror and the focal position of the concave mirror is not less than 45°, so that as many fluorescent photons emitted at an angle of 4π from the target cavity as possible are collected and reflected to the notch filter, ensuring that they are focused on the notch filter and then defocused.
[0017] Preferably, the center line of the incident port, the axis of the target cavity and the axis of the reflector are located on the same horizontal line.
[0018] In this way, the center line of the incident port, the axis of the target cavity and the axis of the reflector are located on the same horizontal line, so that the incident laser and the reflected laser can be kept on the same axis as much as possible, thereby ensuring the output rate of the two-photon absorption process of the target atomic vapor in the target cavity, and then ensuring the number of fluorescent photons received by the photomultiplier tube.
[0019] Preferably, the inner wall of the shell is coated with a light absorbing layer made of a light absorbing material.
[0020] In this way, the light-absorbing layer made of the light-absorbing material can effectively absorb the stray light entering the housing, further reducing the influence of the stray light on the measurement result of the photomultiplier tube.
[0021] Preferably, the reflector is a total reflector with the back side silver-plated.
[0022] In this way, the silver-coated total reflection mirror on the back can ensure the reflection effect of the incident laser beam.
[0023] Preferably, the target cavity is a fully sealed target cavity made of glass material.
[0024] In this way, the fully sealed target cavity can ensure the absorption effect of incident light and reflected light, thereby ensuring the measurement effect of the photomultiplier tube.
[0025] Compared with the prior art, the utility model has the following advantages:
[0026] 1. This scheme installs a concave mirror with a larger aperture at the lower end of the target cavity, with the focus behind the notch filter, to reflect and collect fluorescent photons, so that as many fluorescent photons emitted from the target cavity at an angle of 4π as possible are collected and reflected behind the notch filter, ensuring that they are focused on the notch filter and then defocused.
[0027] 2. By coating the inner wall of the collecting tube behind the notch filter with reflective material, the fluorescent photons reaching the notch filter can be received by the PMT sealed and installed in the collecting tube as much as possible after multiple reflections.
[0028] 3. Through this scheme, the two-photon absorption spectrum signal can be enhanced and the signal-to-noise ratio can be improved. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 A schematic diagram of the structure of a device for increasing the collection efficiency of monochromatic fluorescent photons according to the utility model;
[0030] Figure 2A focusing schematic diagram of a concave mirror in a device for increasing the collection efficiency of monochromatic fluorescent photons according to the utility model.
[0031] Explanation of the reference numerals: housing 1 , target cavity 2 , reflecting mirror 3 , collecting tube 4 , photomultiplier tube 5 , notch filter 6 , concave mirror 7 , incident laser 8 . DETAILED DESCRIPTION
[0032] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution of the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings of the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the described embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model. Unless otherwise defined, the technical terms or scientific terms used herein should be the usual meanings understood by people with general skills in the field to which the utility model belongs.
[0033] The words "first", "second" and similar words used in the specification and claims of the utility model patent application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular form of "a", "an" or "the" and other similar words do not indicate a quantitative limitation, but indicate the existence of at least one. "Include" or "comprise" and other similar words mean that the elements or objects appearing before "include" or "comprise" cover the features, wholes, steps, operations, elements and / or components listed after "include" or "comprise", and do not exclude the existence or addition of one or more other features, wholes, steps, operations, elements, components and / or their collections. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0034] As attached Figure 1As shown, a device for increasing the collection efficiency of monochromatic fluorescent photons comprises a housing 1, a side of the housing 1 is provided with an incident port for an incident laser 8 to pass through, a target cavity 2 and a reflector 3 are arranged in the housing 1, the center line of the incident port, the axis of the target cavity 2 and the axis of the reflector 3 are located on the same horizontal line; the center line of the incident port, the axis of the target cavity 2 and the axis of the reflector 3 are located on the same horizontal line, so that the incident laser 8 and the reflected laser can be kept on the same axis as much as possible, so that the output rate of the two-photon absorption process of the target atomic vapor in the target cavity 2 can be guaranteed, and then the number of fluorescent photons received by the photomultiplier tube 5 can be guaranteed. The inner wall of the housing 1 is coated with a light-absorbing layer made of a light-absorbing material; the light-absorbing layer made of a light-absorbing material can effectively absorb the stray light entering the housing 1, and further reduce the influence of the stray light on the measurement result of the photomultiplier tube 5. The reflector 3 is a full reflector 3 with a silver-plated back surface; the full reflector 3 with a silver-plated back surface can ensure the reflection effect of the incident laser 8 beam. The target cavity 2 is a fully sealed target cavity 2 made of glass material; the fully sealed target cavity 2 can ensure the absorption effect of incident light and reflected light, thereby ensuring the measurement effect of the photomultiplier tube 5.
[0035] A collecting tube 4 connected to the inside of the shell 1 is also provided on the top surface of the shell 1, and the collecting tube 4 is located directly above the target cavity 2 and is arranged perpendicular to the target cavity 2; a notch filter 6 is provided at the entrance of the collecting tube 4 close to the shell 1, and the notch filter 6 is movably connected at the entrance of the collecting tube 4; a photomultiplier tube 5 (PMT) is installed at the upper end of the collecting tube 4, and the inner wall of the collecting tube 4 is coated with a reflective layer made of reflective material; the reflective layer is formed by coating the inner wall of the collecting tube 4 with reflective material after the notch filter 6, so that the fluorescent photons reaching the notch filter 6 can be received by the photomultiplier tube 5 sealed and installed in the collecting tube 4 as much as possible after multiple reflections.
[0036] As attached Figure 2 As shown, a concave mirror 7 is also provided in the housing 1. The concave mirror 7 is located below the target cavity 2. The positions of the collecting tube 4, the target cavity 2 and the concave mirror 7 in the vertical direction correspond to each other. The opening of the concave mirror 7 faces the collecting tube 4, and the focus of the concave mirror 7 is located between the notch filter 6 and the photomultiplier tube 5. The width of the concave mirror 7 along the axial direction is greater than the width of the target cavity 2 and the collecting tube 4 along the axial direction. Specifically, the axial ends of the concave mirror 7 (attached Figure 2 The A and B positions in the figure are respectively related to the focal position of the concave mirror 7 (see Figure 2 o) in the figure, and the angle between the two lines should not be less than 45° ( Figure 2Since the fluorescent photons of the target cavity 2 are emitted at an angle of 4π, the angle formed by connecting the two axial ends of the concave mirror 7 with the focal position of the concave mirror 7 is not less than 45°, so that as many fluorescent photons emitted at an angle of 4π from the target cavity 2 as possible are collected and reflected to the notch filter 6, ensuring that they are focused on the notch filter 6 and then defocused.
[0037] In this way, when the device of this scheme is in use, the incident laser 8 generated by the laser enters the outer shell 1 through the incident port, and the incident laser 8 entering the outer shell 1 further enters the target material cavity 2, and the incident laser 8 entering the target material cavity 2 is absorbed by the target material atomic vapor in the target material cavity 2, and transitions to a metastable structure, and then the incident laser 8 further passes through the target material cavity 2 and is emitted from its rear end and hits the reflector 3, and the reflector 3 reflects the incident laser 8 to form a reflected laser and enters the target material cavity 2 again, and the reflected laser entering the target material cavity 2 is absorbed by the target material atomic vapor for the second time, and the extranuclear electrons in the metastable structure are excited to a better energy state, and when the excited electrons de-excite to the ground state, fluorescent photons of a specific wavelength are emitted, and the fluorescent photons are collected in the target material cavity 2 and gathered into the collecting tube 4, and the fluorescent photons gathered in the collecting tube 4 are further absorbed by the photomultiplier tube 5, thereby achieving the purpose of experimental measurement of two-photon absorption.
[0038] In the process of collecting fluorescent photons in this scheme, since the housing 1 is coated with a black light-absorbing material and the incident port has a small diameter, a concave mirror 7 with a larger diameter is arranged at the lower end of the target cavity 2, and the opening of the concave mirror 7 is directed toward the collecting tube 4. The collecting tube 4, the target cavity 2 and the concave mirror 7 correspond to each other in the vertical direction, and the focus of the concave mirror 7 is located between the notch filter 6 and the photomultiplier tube 5. Since the fluorescent photons emitted by the target cavity 2 are emitted at an angle of 4π, the concave mirror 7 is arranged at the lower end of the target cavity 2. The concave mirror 7 can reflect as many fluorescent photons dispersedly emitted by the target cavity 2 as possible toward the collecting tube 4, thereby greatly increasing the number of fluorescent photons reaching the collecting tube 4, thereby making more The fluorescent photons are detected by the photomultiplier tube 5; at the same time, by installing a notch filter 6 at the entrance of the collecting tube 4, the notch filter 6 can only allow fluorescent photons of a specific wavelength to pass through, while photons of other wavelengths are reflected. Since the light converged at the collecting tube 4 includes not only fluorescent photons but also part of the scattered light of the incident light and some stray light from the outside, by setting the notch filter 6, as many fluorescent photons as possible that need to be collected can pass through the notch filter 6 and reach the photomultiplier tube 5 to be absorbed, while the scattered light and stray light of the incident light can be reflected as much as possible, thereby reducing the influence of the scattered light and stray light of the incident light, further improving the signal-to-noise ratio of the two-photon absorption spectrum, and ensuring the accuracy of the fluorescence photon detection result of the photomultiplier tube 5.
[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit the technical solution. Ordinary technicians in this field should understand that those modifications or equivalent replacements of the technical solution of the utility model without departing from the purpose and scope of the technical solution of the utility model should be included in the scope of the claims of the utility model.
Claims
1. A device for increasing the efficiency of collecting monochromatic fluorescence photons, characterized in that: The invention comprises a shell, a side of which is provided with an incident port for incident laser to pass through, a target cavity, a reflecting mirror and a concave mirror are arranged in the shell, a collecting tube connected with the inside of the shell is also arranged on the top surface of the shell, a notch filter is arranged at the entrance of the shell near the collecting tube, a photomultiplier tube is installed at the upper end of the collecting tube, the concave mirror is located below the target cavity, the collecting tube, the target cavity and the concave mirror are located in corresponding positions in the vertical direction, the opening of the concave mirror faces the collecting tube, and the focus of the concave mirror is located between the notch filter and the photomultiplier tube.
2. The device for increasing the collection efficiency of monochromatic fluorescence photons according to claim 1, characterized in that: The inner wall of the collecting tube is coated with a reflective layer made of reflective material.
3. The device for increasing the collection efficiency of monochromatic fluorescence photons according to claim 1, characterized in that: The notch filter is movably connected to the inlet of the collecting cylinder.
4. The device for increasing the collection efficiency of monochromatic fluorescence photons according to claim 1, characterized in that: The width of the concave mirror along the axial direction is greater than the width of the target cavity and the collecting tube along the axial direction.
5. The device for increasing the collection efficiency of monochromatic fluorescence photons according to claim 1, characterized in that: The two axial ends of the concave mirror are respectively connected to the focal position of the concave mirror, and the angle formed by the two connecting lines is not less than 45°.
6. The device for increasing the collection efficiency of monochromatic fluorescence photons according to claim 1, characterized in that: The center line of the incident port, the axis of the target cavity and the axis of the reflector are located on the same horizontal line.
7. The device for increasing the collection efficiency of monochromatic fluorescence photons according to claim 5, characterized in that: The inner wall of the shell is coated with a light absorbing layer made of light absorbing material.
8. The device for increasing the collection efficiency of monochromatic fluorescence photons according to claim 5, characterized in that: The reflector is a total reflector with silver plated on the back.
9. The device for increasing the collection efficiency of monochromatic fluorescence photons according to claim 1, characterized in that: The target cavity is a fully sealed target cavity made of glass material.