A material detection optical system based on photoluminescence spectrometer

Abstract

The present invention relates to a material detection optical system based on a photoluminescence spectrometer, comprising a converging portion, a dichroic mirror, a fluorescence converging mirror, an entrance slit, and a spectrometer. The spectrometer includes a first concave reflector, a blazed grating, and a second concave reflector. The converging portion includes a first lens and a second lens arranged sequentially along an optical path. The first and second concave reflectors are off-axis concave reflectors. A light beam converged by the converging lens passes through a material sample. The sample is excited by the light beam to produce fluorescence. After reflection by the dichroic mirror, the light beam passes through the converging lens. The converged light beam passes through the entrance slit and is incident on the first concave reflector. After reflection by the blazed grating, the light beam is split by the second concave reflector and finally detected by a detection portion. The material detection optical system of the photoluminescence spectrometer of the present invention can perform optical analysis or testing of materials over a wide spectral range and has the advantages of being compact and lightweight.

Description

Technical Field

[0001] The present invention relates to the field of spectrum analysis systems, and in particular to a material detection optical system based on a photoluminescence spectrometer. Background Art

[0002] Photoluminescence spectrometers can obtain information about a material's luminescence characteristics from its spectrum, such as peak wavelength, luminescence intensity, and half-width (FWHM). This information can then be used to study the material's band structure, defect states, impurity content, and other properties. Photoluminescence spectrometers are widely used in fields such as materials science, semiconductor physics, chemistry, and biomedicine. The main principle behind this is that photoluminescence is the phenomenon in which a material absorbs photon energy and then re-emit photons through electronic energy level transitions.

[0003] Traditional photoluminescence spectrometers typically use optical systems to separate light and precisely measure wavelengths. However, most existing photoluminescence spectrometers have a limited spectral range, typically covering only the ultraviolet or visible regions. Applications that require simultaneous detection of ultraviolet, visible, and near-infrared spectra often require multiple devices or complex optical systems. This approach not only increases the size and weight of the equipment but also reduces the flexibility of the system, making it difficult to meet the demands of modern applications for miniaturization and portability. Summary of the Invention

[0004] To address the shortcomings of the existing technology, the present invention provides a material detection optical system based on a photoluminescence spectrometer, which can cover a wide spectral range of 200nm to 900nm, that is, it can simultaneously detect wavelengths in the ultraviolet spectral region of 200nm to 380nm, the visible light spectral region of 380nm to 780nm, and the near-infrared spectral region of 780nm to 900nm. Moreover, through optimized design, a miniaturized and lightweight structure is achieved, greatly enhancing the flexibility of the photoluminescence spectrometer system.

[0005] This patented method utilizes an integrated optical design, enabling the detection of very weak luminescence signals from samples using low-power lasers or broadband light sources. Even small amounts of luminescent centers or luminescent substances in a sample can be effectively detected and analyzed using a photoluminescence spectrometer, making it uniquely advantageous for studying low-concentration impurities and defect luminescence.

[0006] The present invention specifically relates to a material detection optical system based on a photoluminescence spectrometer, comprising: a first converging portion (1) composed of a first lens (11) and a second lens (12) arranged in sequence along an optical path, a dichroic mirror (2), a fluorescence converging mirror (3), an incident slit (4), a first concave reflector (5), a blazed grating (6), a second concave reflector (7), and a detection portion (8); the first lens (11), the second lens (12), and the third lens (3) are all spherical mirrors, the first concave reflector (5) and The second concave reflector (7) is an off-axis concave reflector; the light beam converged by the converging lens (1) passes through the material sample, and the sample generates fluorescence after being excited by the light beam. After being reflected by the dichroic mirror (2), the light beam passes through the converging lens (3). The converged light beam passes through the incident slit (4) and is incident on the first concave reflector (5). After reflection, the light beam is split by the blazed grating (6), and after splitting, it passes through the second concave reflector (7) and is finally detected by the detection unit (8); the optical focal length of the second reflector is Φ 57， The optical power of the spectrophotometer optical system is Φ, which satisfies the following relationship: 0.32<Φ 57 / Φ<0.7; the optical path from the laser to the sample is L1, and the optical path from the laser to the detection part (8) is L, which satisfies the following relationship: 3.3≤L1 / L≤4.5.

[0007] Furthermore, the converging portion (1) includes one or more optical converging elements, and the converging portion (1) is capable of converging the light beam emitted by the laser to be incident on the sample surface; the optical path from the laser to the sample is L1, and the optical path from the laser to the detection portion (8) is L, which satisfies the following relationship: 3.3≤L1 / L≤4.5, and the optical focal length Φ of the converging lens (1) is 1， The focal power Φ of the converging first lens (11) 11 , the focal power Φ of the converging first lens (12) 12， The optical power of the material detection optical system is Φ, which satisfies the following relationship: Φ 11 =Φ 12 , 0.1≤Φ1 / Φ≤0.25.

[0008] Furthermore, the dichroic mirror (2) has an inclination angle of θ1, which satisfies the following relationship: θ1=45°.

[0009] Furthermore, the focal length of the fluorescence converging lens (3) is Φ3, and the focal length of the material detection optical system is Φ, which satisfy the following relationship: 0.08≤Φ3 / Φ≤0.2.

[0010] Furthermore, the width of the incident slit (4) is w, which satisfies the following relationship: w≤0.02.

[0011] Furthermore, the first concave reflecting mirror (5) has a curvature R1, an inclination angle θ2, and an eccentricity Y1, which satisfies the following relationship: -0.025≤R1≤-0.01, 10°≤θ2≤15°, and 13.5≤Y1≤15.

[0012] Furthermore, the reflection grating is a blazed grating (6), the blazed wavelength λ of the blazed grating and the tilt angle θ3 satisfy the following relationship: ， Satisfying 450 nm≤λ≤625 nm, 25°≤θ2≤35°.

[0013] Furthermore, the second concave reflecting mirror (7) has a curvature R2, an inclination angle θ4, and an eccentricity Y2, which satisfies the following relationship: -0.02≤R2≤-0.01, 75°≤θ2≤85°, and -28≤Y1≤-20.

[0014] Furthermore, the first concave reflecting mirror (5), the first concave reflecting mirror curvature R1, the second concave reflecting mirror (7), the second concave reflecting mirror curvature R2, satisfy the following relationship: 0.8≤R 2 / R1≤1.

[0015] Furthermore, the first concave reflecting mirror (5), the reflecting grating is a blazed grating (6), and the second concave reflecting mirror (7), along the propagation direction of light, the interval between the first concave reflecting mirror (5) and the reflecting grating is the blazed grating (6) is m1, and the interval between the reflecting grating is the blazed grating (6) and the second concave reflecting mirror (7) is m2, which satisfies the following relationship: 0.8≤m1 / m2≤1.8.

[0016] The material detection optical system based on the photoluminescence spectrometer provided by the present invention can clearly reveal the spectral distribution of different materials after optimizing its component design. Compared with traditional ordinary optical microscopes that can only observe sample morphology, surface structure and other characteristics, the material detection optical system based on the photoluminescence spectrometer can analyze the luminescence mechanism, band structure or chemical composition of the material. In addition, the material detection optical system based on the photoluminescence spectrometer adopts an integrated excitation-detection design, which is more conducive to the control of aberrations and further improves the overall reliability of the system.

[0017] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0019] Figure 1 The structure and optical path diagram of a material detection optical system based on a photoluminescence spectrometer according to one embodiment of the present invention are shown;

[0020] Figure 2 FIG2 shows a schematic diagram of displaying a diffuse spot corresponding to a material detection optical system based on a photoluminescence spectrometer according to an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of a curve of a modulation transfer function corresponding to a material detection optical system based on a photoluminescence spectrometer according to an embodiment of the present invention is shown.

[0022] Reference numerals: 1 - first converging portion, 11 - first lens, 12 - second lens, 2 - dichroic mirror, 3 - fluorescence converging mirror, 4 - entrance slit, 5 - first concave reflecting mirror, 6 - blazed grating, 7 - second concave reflecting mirror, 8 - detection portion. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below with reference to the accompanying drawings: the described embodiments are only part of the embodiments of the present invention, not all of them. The following embodiments are only for more clearly illustrating the technical solutions of the present invention and cannot be used to limit the scope of protection of the present invention.

[0024] It should be noted that the unit of optical power in the present invention is mm. -1 The unit of curvature radius is mm, and the unit of eccentricity is mm.

[0025] In the embodiment disclosed in the present invention, a material detection optical system based on a photoluminescence spectrometer includes, in order of the optical path, a first converging portion 1 composed of a first lens 11 and a second lens 12 arranged in sequence along the optical path, a dichroic mirror 2, a fluorescence converging mirror 3, an incident slit 4, a second reflecting portion composed of a first concave reflecting mirror 5, a blazed grating 6 and a second concave reflecting mirror 7, and a detection portion 8.

[0026] The first converging part 1 can converge the incident light beam so that the excitation light beam is focused on the material to be tested, so as to better excite the fluorescence; the dichroic mirror 2 is arranged on the converging side of the first converging part 1, and the dichroic mirror 2 is located on the extension line of the incident light axis, which can split the laser beam and the fluorescence to prevent the laser beam from entering the subsequent system as stray light; the fluorescence converging mirror 3 is arranged on the reflected light path of the dichroic mirror 2 to converge the fluorescence reflected by the dichroic mirror 2; the incident slit 4 is arranged on the extension line of the optical axis of the fluorescence converging mirror 3, which can improve the spectral resolution, suppress stray light, and improve the signal-to-noise ratio; the first concave reflecting mirror 5 is used to collimate the incident light beam, the blazed grating 6 is used to perform spectral splitting, and the second concave reflecting mirror 7 converges the split light beams separately to realize the detection of light beams in different bands.

[0027] The incident light beam enters the first converging part 1, is converged by the first lens 11 and the second lens 12 in sequence, passes through the material sample, and the sample produces fluorescence after being excited by the light beam. After being reflected by the dichroic mirror 2, it passes through the fluorescence converging mirror 3. The converged light beam passes through the incident slit 4 and is incident on the first concave reflector 5. After reflection, it is split by the blazed grating 6, and after splitting, it passes through the second concave reflector 7 and is finally detected by the detection part 8.

[0028] In one embodiment, the first lens 11 , the second lens 12 , and the fluorescence converging mirror 3 are all spherical mirrors, and the first concave reflecting mirror 5 and the second concave reflecting mirror 7 are both off-axis concave reflecting mirrors.

[0029] In a preferred embodiment, Figure 1 As shown, the optical path from the laser to the sample is L1, and the optical path from the laser to the detection unit 8 is L, which satisfies the following relationship: 3.3≤L1 / L≤4.5. It should be noted that the optical system disclosed in the present invention converges the incident laser through the first converging portion, thereby achieving better sampling of the sample; in addition, in particular, the optical system disclosed in the present invention sets the optical path from the laser to the sample to L1 and the optical path from the laser to the detection unit 8 to L to 3.3≤L1 / L≤4.5, which can ensure that the material detection optical system can achieve good imaging quality over a wide spectrum range while being small in size.

[0030] In a preferred embodiment, Figure 1 As shown, the first converging portion 1 can converge the light beam emitted by the laser to be incident on the sample surface, the optical focal length of the first converging portion 1 is Φ1, and the optical focal length of the first lens 11 is Φ 11 , the focal length of the second lens 12 is Φ 12 , the optical power of the material detection optical system is Φ, which satisfies the following relationship: Φ 11 =Φ 12 , 0.1≤Φ1 / Φ≤0.25.

[0031] In a preferred embodiment, Figure 1 As shown, the tilt angle of the dichroic mirror 2 is θ1, which satisfies the following relationship: θ1=45°.

[0032] In a preferred embodiment, Figure 1 As shown, the focal power of the fluorescence converging lens 3 is Φ3, and the focal power of the material detection optical system is Φ, which satisfies the following relationship: 0.08≤Φ3 / Φ≤0.2.

[0033] In a preferred embodiment, Figure 1 As shown, the width of the incident slit 4 is w, which satisfies the following relationship: 0.02≤w.

[0034] In a preferred embodiment, Figure 1 As shown, the curvature R1, the tilt angle θ2, and the eccentricity Y1 of the first concave reflecting mirror 5 satisfy the following relationship: -0.025≤R1≤-0.01, 10°≤θ2≤15°, and 13.5≤Y1≤15.

[0035] In a preferred embodiment, Figure 1 As shown, the blazing wavelength λ of the blazed grating 6 and the tilt angle θ3 satisfy the following relationship: 450nm≤λ≤625nm, 25°≤θ3≤35°.

[0036] In a preferred embodiment, Figure 1 As shown, the curvature R2, the tilt angle θ4, and the eccentricity Y2 of the second concave reflecting mirror 7 satisfy the following relationship: -0.02≤R2≤-0.01, 75°≤θ4≤85°, and -28≤Y2≤-20.

[0037] In a preferred embodiment, Figure 1 As shown, the curvature R1 of the first concave reflecting mirror 5 and the curvature R2 of the second concave reflecting mirror 7 satisfy the following relationship: 0.8≤R 2 / R1≤1.

[0038] In a preferred embodiment, Figure 1 As shown, the optical power of the second reflecting part is Φ 57 , the optical power of the material detection optical system is Φ, which satisfies the following relationship: 0.32<Φ 57 / Φ<0.7.

[0039] In a preferred embodiment, Figure 1As shown, the first concave reflector 5, the blazed grating 6, and the second concave reflector 7, along the propagation direction of light, the optical path from the first concave reflector 5 to the blazed grating 6 is m1, and the optical path from the blazed grating 6 to the second concave reflector 7 is m2, which satisfies the following relationship: 0.8≤m1 / m2≤1.8.

[0040] By optimizing the parameter design of each optical component of the optical system, the present invention can realize imaging in a wide spectral range of 200nm to 900m, and can achieve high-quality optical imaging effects while ensuring miniaturization and lightweight.

[0041] It is particularly important to note that the present invention can further ensure the miniaturization of the overall detection system and achieve high-quality optical imaging effects through the design of the optical path between the optical elements of the second reflecting part and the ratio design between the optical focal length of the second reflecting part and the optical focal length of the entire optical system.

[0042] A specific embodiment of the present invention and its performance effects are provided below to assist in illustrating:

[0043] See also Figure 1 In the material detection optical system based on the photoluminescence spectrometer, the optical power Φ of the entire material detection optical system is 0.5, the first converging part 1 is composed of the first lens 11 and the second lens 12 along the incident light axis, and its optical power Φ1 is 0.1, and the optical power Φ 11 is 0.05, and the focal length of the second lens 12 is Φ 12 The total length (along the incident optical axis) of the entire first converging portion 1 (including the first lens 11, the second lens 12, and the assembly for securely connecting the first lens 101 and the second lens 102) is 18 mm. This design reduces system aberrations and achieves a lighter overall weight than a single-piece converging lens.

[0044] The converging portion 1 and the dichroic mirror 2 are connected by a light-shielding component. The body of the dichroic mirror 2 intersects with the extension line of the incident light axis, and is used to split the laser beam and the fluorescence.

[0045] The fluorescence converging mirror 3 is arranged on the reflected light path of the dichroic mirror 2 to converge the fluorescence reflected by the dichroic mirror 2. The optical power Φ3 of the fluorescence converging mirror 3 is 0.05, and the distance between its exit surface and the incident slit 4 is 9.7 mm.

[0046] The incident slit 4 is arranged between the fluorescent converging lens 3 and the second reflecting part, and is located at the exit focus of the fluorescent converging lens 3. The lateral distance from the center of curvature of the converging lens 3 is 9 mm. A slit is provided on it that intersects and is perpendicular to the extension line of the incident light axis. Only light refracted by the converging lens 3 is allowed to pass through. The slit is 4.5 mm long and 0.1 mm wide to accommodate light in the wavelength range of 200 nm to 900 nm.

[0047] The first concave reflecting mirror 5 is used to collimate the incident light beam. Its curvature radius is -0.01, the tilt angle is 10°, the eccentricity is 13.7, and the distance from its curvature center to the incident slit 2 (along the direction of the incident light axis) is 42 mm.

[0048] The blazed grating 6 has a grating constant of 3 μm, a tilt angle of 27°, a blazing wavelength of 500 nm, and a lateral distance (i.e., a direction parallel to the incident light axis) between the grating center and the curvature center of the first converging lens 3 of 22 mm.

[0049] The second concave reflecting mirror 7 has a curvature radius of -0.01, an inclination angle of 77°, an eccentricity of -27.5 mm, and a lateral distance from its curvature center to the beam splitting reflection grating 4 of 28 mm.

[0050] The second reflector consists of a first concave reflector 5, a blazed grating 6, and a second concave reflector 7. Along the light propagation direction, the optical path from the first concave reflector 5 to the blazed grating 6 is 33 mm, and the optical path from the blazed grating 6 to the second concave reflector 7 is 29.3 mm.

[0051] The imaging effect of this specific embodiment can be seen in Figure 2 , Figure 2 The figure shows the diffuse spots corresponding to the material detection optical system in this embodiment: at different lateral positions of the object plane (4.666mm, 3.789mm, and 2.908mm) and corresponding image plane positions, light spots with wavelengths of 200nm (ultraviolet), 300nm (ultraviolet only), 400nm (approximately violet light), 500nm (approximately blue light), 600nm (approximately green light), 700nm (approximately orange light), 800nm ​​(approximately red light), and 900nm (near-infrared) are gathered and imaged from bottom to top at the corresponding image plane according to wavelength. It can be seen that on the lateral scale, the distribution of each light spot is relatively concentrated, and the distribution of light spots of each wavelength on the image plane is concentrated in the middle part of the image; the position and size of the diffuse spots vary slightly at different angles, but there is no obvious diffusion; the diffuse spot distribution is highly concentrated from short wave to long wave range; this shows that the material detection optical system has high imaging accuracy for light of different wavelengths, good aberration control effect, high imaging stability, and can achieve good imaging quality over a wide spectrum range.

[0052] Figure 3 A schematic diagram of the modulation transfer function (MTF) curve of the photoluminescence spectrometer-based material detection optical system of the present invention is shown. The dotted dashed line at the top of the figure, which is close to a straight line, represents the diffraction limit, which is the theoretical maximum resolving power of the lens assembly. The other curves are schematic diagrams of the modulation transfer function (MTF) curves of the photoluminescence spectrometer-based material detection optical system of the present invention at multiple field angles. As can be seen from the figure, the MTF of the photoluminescence spectrometer-based material detection optical system proposed in the present invention at a spatial frequency of 100 lp / mm over the entire field of view is greater than 0.3, indicating excellent resolving power.

[0053] Therefore, the material detection optical system based on the photoluminescence spectrometer provided by the present invention can clearly reveal the spectral distribution of different materials after optimizing the component design. Compared with traditional ordinary optical microscopes that can only observe sample morphology, surface structure and other characteristics, the material detection optical system based on the photoluminescence spectrometer can analyze the luminescence mechanism, band structure or chemical composition of the material. In addition, the material detection optical system based on the photoluminescence spectrometer adopts an integrated excitation-detection design, which is more conducive to the control of aberrations and further improves the overall reliability of the system.

[0054] In addition, as mentioned above, the present invention can achieve imaging in a wide spectral range of 200nm to 900m by optimizing the parameter design of each optical component of the optical system, and can achieve high-quality optical imaging effects while ensuring miniaturization and lightweight.

[0055] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention is not limited to the embodiments described in the specific implementation methods. Any other implementation methods derived by those skilled in the art based on the technical solutions of the present invention also fall within the scope of protection of the present invention.

Claims

1. A material detection optical system based on a photoluminescence spectrometer, characterized in that: The material detection optical system based on the photoluminescence spectrometer comprises: A laser, a first converging portion (1) consisting of a first lens (11) and a second lens (12) arranged in sequence along an optical path, a dichroic mirror (2), a fluorescence converging mirror (3), an incident slit (4), a second reflecting portion consisting of a first concave reflecting mirror (5), a blazed grating (6) and a second concave reflecting mirror (7), and a detecting portion (8); The first lens (11), the second lens (12), and the fluorescent converging mirror (3) are all spherical mirrors, and the first concave reflecting mirror (5) and the second concave reflecting mirror (7) are both off-axis concave reflecting mirrors; The light beam converged by the first converging portion (1) passes through a material sample, and the sample generates fluorescence after being excited by the light beam. The light beam is reflected by the dichroic mirror (2) and then passes through the fluorescence converging mirror (3). The converged light beam passes through the incident slit (4) and is incident on the first concave reflector (5). After reflection, the light beam is split by the blazed grating (6), and then passes through the second concave reflector (7) and finally detected by the detection portion (8). The optical power of the second reflecting part is Φ 57， The optical power of the material detection optical system is Φ, which satisfies the following relationship: 0.32<Φ 57 / Φ<0.7; the optical path from the laser to the sample is L1, and the optical path from the laser to the detection part (8) is L, which satisfies the following relationship: 3.3≤L1 / L≤4.5; The first converging portion (1) is capable of converging the light beam emitted by the laser and incident on the sample surface. The optical focal length of the first converging portion (1) is Φ1, and the optical focal length of the first lens (11) is Φ 11 , the optical power Φ of the second lens (12) 12， The optical power of the material detection optical system is Φ, which satisfies the following relationship: Φ 11 =Φ 12 , 0.1≤Φ1 / Φ≤0.25; The focal length of the fluorescence converging mirror (3) is Φ3, and the focal length of the material detection optical system is Φ, which satisfies the following relationship: 0.08≤Φ3 / Φ≤0.2; The first concave reflecting mirror (5) has a curvature R1, an inclination angle θ2, and an eccentricity Y1, which satisfies the following relationship: -0.025≤R1≤-0.01, 10°≤θ2≤15°, and 13.5≤Y1≤15; The second concave reflecting mirror (7) has a curvature R2, an inclination angle θ4, and an eccentricity Y2, which satisfy the following relationship: -0.02≤R2≤-0.01, 75°≤θ4≤85°, -28≤Y2≤-20; The first concave reflecting mirror (5) has a curvature R1, and the second concave reflecting mirror (7) has a curvature R2, which satisfy the following relationship: 0.8≤R 2 / R1≤1.

2. The material detection optical system according to claim 1, wherein: The dichroic mirror (2) has an inclination angle of θ1, which satisfies the following relationship: θ1=45°.

3. The material detection optical system according to claim 1, wherein: The width of the incident slit (4) is w, which satisfies the following relationship: w≤0.

02.

4. The material detection optical system according to claim 1, wherein: The blazing wavelength λ of the blazing grating (6) and the tilt angle θ3 satisfy the following relationship: 450 nm≤λ≤625 nm, 25°≤θ3≤35°.

5. The material detection optical system according to any one of claims 1 to 4, characterized in that: The first concave reflector (5), the blazed grating (6), and the second concave reflector (7), along the propagation direction of light, the optical path from the first concave reflector (5) to the blazed grating (6) is m1, and the optical path from the blazed grating (6) to the second concave reflector (7) is m2, which satisfy the following relationship: 0.8≤m1 / m2≤1.8.

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