Material detection optical system based on photoluminescence spectrometer

Abstract

The invention relates to a material detection optical system based on a photoluminescence spectrograph, which comprises a convergence part, a dichroscope, a fluorescent convergent mirror, an entrance slit and a spectrograph, the spectrograph comprises a first concave reflector, a blazed grating and a second concave reflector, the convergence part comprises a first lens and a second lens which are sequentially arranged along a light path, and the first lens and the second lens are arranged along the light path. The first concave reflector and the second concave reflector are off-axis concave reflectors, light beams converged by the convergent lens pass through the material sample, the sample is excited by the light beams to generate fluorescent light, the fluorescent light is reflected by the dichroscope and then passes through the convergent lens, and the fluorescent light is reflected by the dichroscope. The converged light beam enters the first concave reflecting mirror through the entrance slit to be reflected, then is split through the blazed grating, passes through the second concave reflecting mirror after being split, and finally is detected through the detection part. The material detection optical system of the photoluminescence spectrometer can realize material optical analysis or test in a wide spectral range, and has the advantages of miniaturization and light weight.

Description

Technical Field

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

[0002] A photoluminescence spectrometer can obtain information on the luminescence characteristics of a material from the spectrum, such as the peak emission wavelength, emission intensity, full width at half maximum, etc., and then study the properties of the material such as the energy band structure, defect state, impurity content, etc. It has a wide range of applications in many fields such as materials science, semiconductor physics, chemistry, biomedicine, etc. Its main principle is that photoluminescence is a phenomenon in which a material absorbs photon energy and then re-emits photons through electron energy level transitions.

[0003] Traditional photoluminescence spectrometers usually achieve the separation of light and the precise measurement of wavelength through an optical system. However, in the prior art, most photoluminescence spectrometers have a limited spectral range and usually can only cover the ultraviolet spectral region or the visible spectral region. In applications that require simultaneous detection of ultraviolet, visible, and near-infrared spectra, multiple devices or complex optical systems are often required to complete the task. This method not only increases the volume and weight of the equipment but also reduces the flexibility of the system, making it difficult to meet the requirements of modern applications for miniaturization and portability. Summary of the Invention

[0004] To solve the deficiencies of the prior art, the present invention provides a material detection optical system based on a photoluminescence spectrometer, which can cover a wide spectral range from 200 nm to 900 m, that is, it can detect wavelengths in the ultraviolet spectral region of 200 nm - 380 nm, the visible spectral region of 380 nm - 780 nm, and the near-infrared spectral region of 780 nm - 900 m at the same time; and through optimized design, a miniaturized and lightweight structure is achieved, greatly improving the flexibility of the photoluminescence spectrometer system.

[0005] The present invention patent adopts an integrated optical path design, which can excite the sample with a low-power laser or a broadband light source, and can detect very weak luminescence signals in the sample. Even if there are only a small number of luminescence centers or luminescent substances in the sample, effective detection and analysis can be carried out through a photoluminescence spectrometer, which gives it unique advantages in the study of low-concentration impurities, defect luminescence, etc.

[0006] The present invention specifically relates to a material detection optical system based on a photoluminescence spectrometer, which includes: a first converging part (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 lens (3), an entrance slit (4), a first concave mirror (5), a blazed grating (6), a second concave mirror (7), and a detection part (8); the first lens (11), the second lens (12), and the fluorescence converging lens (3) are all spherical mirrors, and the first concave mirror (5) and the second concave mirror (7) are both off-axis concave mirrors; the light beam converged by the first converging part (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), it passes through the fluorescence converging lens (3). The converged light beam passes through the entrance slit (4) and is incident on the first concave mirror (5) and then reflected. After being spectroscopically analyzed by the blazed grating (6), it passes through the second concave mirror (7), and finally is detected by the detection part (8); the optical power of the second reflecting part is Φ 57， The optical power of the spectrophotometer optical system is Φ, and it 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, and it satisfies the following relationship: 3.3 ≤ L1 / L ≤ 4.5.

[0007] Further, the first converging part (1) includes one or more optical converging elements, and the converging part (1) can converge the light beam emitted by the laser and incident on the surface of the sample; 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, and it satisfies the following relationship: 3.3 ≤ L1 / L ≤ 4.5, and the optical power Φ of the converging lens (1) 1， The optical power Φ of the converging first lens (11) 11 , and the optical power Φ of the converging first lens (12) 12， The optical power of the material detection optical system is Φ, and it satisfies the following relationship: Φ 11 = Φ 12 , 0.1 ≤ Φ1 / Φ ≤ 0.25.

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

[0009] Further, the optical power Φ3 of the fluorescence converging lens (3), and the optical power of the material detection optical system is Φ, and it satisfies the following relationship: 0.08 ≤ Φ3 / Φ ≤ 0.2.

[0010] Further, the width of the entrance slit (4) is w, and it satisfies the following relationship: w ≤ 0.02.

[0011] Further, for the first concave mirror (5), the curvature of the first concave mirror is R1, the tilt angle is θ2, and the eccentricity is Y1, which satisfy the following relationships: -0.025 ≤ R1 ≤ -0.01, 10° ≤ θ2 ≤ 15°, 13.5 ≤ Y1 ≤ 15.

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

[0013] Further, for the second concave mirror (7), the curvature of the second concave mirror is R2, the tilt angle is θ4, and the eccentricity is Y2, which satisfy the following relationships: -0.02 ≤ R2 ≤ -0.01, 75° ≤ θ2 ≤ 85°, -28 ≤ Y1 ≤ -20.

[0014] Further, for the first concave mirror (5) with the curvature of the first concave mirror being R1 and the second concave mirror (7) with the curvature of the second concave mirror being R2, they satisfy the following relationship: 0.8 ≤ 2 / R1 ≤ 1.

[0015] Further, for the first concave mirror (5), the reflection grating is a blazed grating (6), and the second concave mirror (7). Along the light propagation direction, the distance between the first concave mirror (5) and the blazed grating (6) is m1, and the distance between the blazed grating (6) and the second concave mirror (7) is m2, which satisfy the following relationship: 0.8 ≤ m1 / m2 ≤ 1.8 The material detection optical system based on a photoluminescence spectrometer provided by the present invention, after optimizing the component design, can clearly reveal the spectral distribution of different materials. Compared with a traditional ordinary optical microscope that can only observe features such as the morphology and surface structure of a sample, the material detection optical system based on a photoluminescence spectrometer can analyze the luminescence mechanism, energy band structure, or chemical composition of the material. Moreover, the material detection optical system based on a photoluminescence spectrometer adopts an excitation-detection integrated design, which is more conducive to the control of aberrations and further improves the overall reliability of the system.

[0016] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present invention and, together with the specification, are used to explain the principles of the present invention.

[0018] Figure 1 Shows the structural and optical path schematic diagram of a material detection optical system based on a photoluminescence spectrometer according to an embodiment of the present invention; Figure 2 Shows the display schematic diagram of the diffraction spot corresponding to the material detection optical system based on a photoluminescence spectrometer according to an embodiment of the present invention; Figure 3 Shows the curve schematic diagram of the modulation transfer function corresponding to the material detection optical system based on a photoluminescence spectrometer according to an embodiment of the present invention.

[0019] Reference numerals: 1 - first converging part, 11 - first lens, 12 - second lens, 2 - dichroic mirror, 3 - fluorescence converging lens, 4 - entrance slit, 5 - first concave mirror, 6 - blazed grating, 7 - second concave mirror, 8 - detection part. Detailed implementation manners

[0020] The following further details the present invention with reference to the accompanying drawings: The described embodiments are only a part of the embodiments of the present invention, rather than all of them. The following embodiments are only for more clearly explaining the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0021] It should be noted that in the present invention, the unit of optical power is mm, the unit of radius of curvature is mm, and the unit of decentration is mm.

[0022] In the embodiments disclosed in the present invention, in the order of the optical path, a material detection optical system based on a photoluminescence spectrometer includes: a first converging part 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 lens 3, an entrance slit 4, a second reflection part composed of a first concave mirror 5, a blazed grating 6 and a second concave mirror 7, and a detection part 8.

[0023] The first converging part 1 can converge the incident light beam to focus the excitation light beam on the material to be measured for better fluorescence excitation; the dichroic mirror 2 is arranged on the converging side of the first converging part 1 and is located on the extension line of the incident optical axis, and can split the laser beam and fluorescence to prevent the laser beam from entering the subsequent system as stray light; the fluorescence converging lens 3 is arranged on the reflection optical path of the dichroic mirror 2 to converge the fluorescence reflected by the dichroic mirror 2; the entrance slit 4 is arranged on the extension line of the optical axis of the fluorescence converging lens 3, and its function is to improve the spectral resolution, suppress stray light, and improve the signal-to-noise ratio; the first concave mirror 5 is used to collimate the incident light beam, the blazed grating 6 is used for spectral splitting, and the second concave mirror 7 converges the split light beams respectively to realize the detection of light beams in different wavelength bands.

[0024] The incident light beam enters the first converging part 1. After being sequentially converged by the first lens 11 and the second lens 12, it passes through the material sample. After the sample is excited by the light beam, fluorescence is generated. After being reflected by the dichroic mirror 2, it passes through the fluorescence converging lens 3. After being converged, the light beam enters the incident slit 4 and is reflected by the first concave mirror 5, and then is spectroscopically analyzed by the blazed grating 6. After spectroscopic analysis, it passes through the second concave mirror 7, and finally is detected by the detection part 8.

[0025] In one embodiment, the first lens 11, the second lens 12, and the fluorescence converging lens 3 are all spherical mirrors, and the first concave mirror 5 and the second concave mirror 7 are both off-axis concave mirrors.

[0026] In a preferred embodiment, as Figure 1 shown, 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, and they satisfy 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 part, so as to achieve 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 as L1 and the optical path from the laser to the detection part 8 as L to 3.3 ≤ L1 / L ≤ 4.5, which can ensure that the material detection optical system can achieve good imaging quality in a wide spectrum range under the condition of a small size.

[0027] In a preferred embodiment, as Figure 1 shown, the first converging part 1 can converge the light beam emitted by the laser and incident on the surface of the sample. The focal power Φ1 of the first converging part 1, the focal power Φ 11 of the first lens 11, the focal power Φ 12 of the second lens 12, and the focal power of the material detection optical system is Φ, and they satisfy the following relationship: Φ 11 = Φ 12 , 0.1 ≤ Φ1 / Φ ≤ 0.25.

[0028] In a preferred embodiment, as Figure 1 shown, the tilt angle of the dichroic mirror 2 is θ1, and it satisfies the following relationship: θ1 = 45°.

[0029] In a preferred embodiment, as Figure 1 shown, the focal power Φ3 of the fluorescence converging lens 3, and the focal power of the material detection optical system is Φ, and they satisfy the following relationship: 0.08 ≤ Φ3 / Φ ≤ 0.2.

[0030] In a preferred embodiment, as Figure 1 shown, the width of the incident slit 4 is w, and it satisfies the following relationship: 0.02 ≤ w.

[0031] In a preferred embodiment, as Figure 1 shown, the curvature R1 of the first concave mirror 5, the tilt angle is θ2, and the eccentricity is Y1, satisfying the following relationships: -0.025 ≤ R1 ≤ -0.01, 10° ≤ θ2 ≤ 15°, 13.5 ≤ Y1 ≤ 15.

[0032] In a preferred embodiment, as Figure 1 shown, the blaze wavelength λ of the blazed grating 6, the tilt angle is θ3, satisfying the following relationships: 450 nm ≤ λ ≤ 625 nm, 25° ≤ θ3 ≤ 35°.

[0033] In a preferred embodiment, as Figure 1 shown, the curvature R2 of the second concave mirror 7, the tilt angle is θ4, and the eccentricity is Y2, satisfying the following relationships: -0.02 ≤ R2 ≤ -0.01, 75° ≤ θ4 ≤ 85°, -28 ≤ Y2 ≤ -20.

[0034] In a preferred embodiment, as Figure 1 shown, the curvature R1 of the first concave mirror 5 and the curvature R2 of the second concave mirror 7 satisfy the following relationship: 0.8 ≤ R 2 / R1 ≤ 1.

[0035] In a preferred embodiment, as Figure 1 shown, the optical power of the second reflecting portion is Φ 57 , and the optical power of the material detection optical system is Φ, satisfying the following relationship: 0.32 < Φ 57 / Φ < 0.7. Through the entrance slit 4 and the second reflecting portion composed of the first concave mirror 5, the blazed grating 6 and the second concave mirror 7, the present invention can In a preferred embodiment, as Figure 1 shown, for the first concave mirror 5, the blazed grating 6, and the second concave mirror 7, along the light propagation direction, the optical path from the first concave mirror 5 to the blazed grating 6 is m1, and the optical path from the blazed grating 6 to the second concave mirror 7 is m2, satisfying the following relationship: 0.8 ≤ m1 / m2 ≤ 1.8.

[0036] By optimizing the parameter design of each optical component of the optical system, the present invention can achieve imaging within a wide spectral range from 200 nm to 900 m, and can achieve a high-quality optical imaging effect on the basis of ensuring miniaturization and light weight.

[0037] It should be particularly noted that through the design of the optical path between the optical elements of the second reflection part and the ratio design between the optical power of the second reflection part and the optical power of the entire optical system, the present invention can further ensure the miniaturization of the overall detection system and achieve a high-quality optical imaging effect.

[0038] The following provides a specific embodiment of the present invention and its performance effects for auxiliary explanation: Refer to Figure 1 , in the optical system for material detection based on a photoluminescence spectrometer, the optical power Φ of the entire optical system for material detection is 0.5. The first converging part 1 is composed of a first lens 11 and a second lens 12 along the incident optical axis, and its optical power Φ1 is 0.1. The optical power Φ 11 of the first lens 11 is 0.05, and the optical power Φ 12 of the second lens 12 is 0.05; the length (in the direction of the incident optical axis) of the entire first converging part 1 (including the first lens 11, the second lens 12, and the component for fixedly connecting the first lens 101 and the second lens 102) is 18 mm. This design reduces the aberration of the system and obtains a lighter total weight than using a single-piece converging lens.

[0039] The converging part 1 is connected to the dichroic mirror 2 by a light-shielding component. The body of the dichroic mirror 2 intersects with the extension line of the incident optical axis, and it is used for splitting the laser beam and fluorescence.

[0040] The fluorescence converging lens 3 is arranged on the reflection optical path of the dichroic mirror 2 to converge the fluorescence reflected by the dichroic mirror 2. The optical power Φ3 of the fluorescence converging lens 3 is 0.05, and the distance between its exit surface and the incident slit 4 is 9.7 mm.

[0041] The incident slit 4 is arranged between the fluorescence converging lens 3 and the second reflection part and is located at the exit focus of the fluorescence converging lens 3. The lateral distance from the curvature center of the converging lens 3 is 9 mm. A slit intersecting and perpendicular to the extension line of the incident optical axis is opened on it, allowing only the light refracted by the converging lens 3 to pass through. The length of the slit is 4.5 mm and the width is 0.1 mm to allow the light in the wavelength range of 200 nm - 900 nm to pass through.

[0042] The first concave mirror 5 is used to collimate the incident light beam. Its radius of curvature is -0.01, the tilt angle is 10°, the eccentricity is 13.7, and the distance (in the direction of the incident optical axis) from its curvature center to the incident slit 2 is 42 mm.

[0043] The blazed grating 6 has a grating constant of 3 μm, a tilt angle of 27°, a blazed wavelength of 500 nm, and the lateral distance (i.e., in the direction parallel to the incident optical axis) from the grating center to the curvature center of the first converging lens 3 is 22 mm.

[0044] The second concave mirror 7 has a radius of curvature of -0.01, an inclination angle of 77°, an eccentricity of -27.5 mm, and the lateral distance from its center of curvature to the spectroscopic reflection grating 4 is 28 mm.

[0045] The second reflection part is composed of the first concave mirror 5, the blazed grating 6 and the second concave mirror 7. Among them, for the first concave mirror 5, the blazed grating 6, and the second concave mirror 7, along the light propagation direction, the optical path from the first concave mirror 5 to the blazed grating 6 is 33 mm, and the optical path from the blazed grating 6 to the second concave mirror 7 is 29.3 mm. For the imaging effect of this specific embodiment, see Figure 2 , Figure 2 which shows the spot diagram corresponding to the material detection optical system in this embodiment: at different lateral positions of the object plane (4.666 mm, 3.789 mm, 2.908 mm) and corresponding image plane positions, for wavelengths of 200 nm (ultraviolet), 300 nm (only ultraviolet), 400 nm (approximately purple light), 500 nm (approximately blue light), 600 nm (approximately green light), 700 nm (approximately orange light), 800 nm (approximately red light), 900 nm (near infrared), the spots are imaged by wavelength from bottom to top at the corresponding image plane. It can be seen that in the lateral scale, the distribution of each spot is relatively concentrated, and the spots of each wavelength are distributed in the middle part of the image; at different angles, the position and size of the spot diagram change slightly, but there is no obvious diffusion; in the range from short wavelength to long wavelength, the distribution of the spot diagram is highly concentrated; indicating 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 in a broad spectrum range.

[0046] Figure 3 which shows the schematic curve diagram of the modulation transfer function of the material detection optical system of the present invention based on the photoluminescence spectrometer. The dotted line at the top and close to the straight line in the figure represents the diffraction limit, which is the theoretically maximum resolution ability of the lens assembly. The other curves are the schematic curve diagrams of the modulation transfer function of the material detection optical system of the present invention based on the photoluminescence spectrometer at multiple field angles. It can be seen from the figure that the MTF of the material detection optical system of the present invention based on the photoluminescence spectrometer at a spatial frequency of 100 lp / mm in the full field is greater than 0.3, having excellent resolution ability.

[0047] Therefore, the material detection optical system based on a photoluminescence spectrometer provided by the present invention, after optimizing the component design, can clearly reveal the spectral distribution of different materials. Compared with a traditional ordinary optical microscope that can only observe features such as the morphology and surface structure of a sample, the material detection optical system based on a photoluminescence spectrometer can analyze the luminescence mechanism, energy band structure, or chemical composition of the material. Moreover, the material detection optical system based on a photoluminescence spectrometer adopts an excitation-detection integrated design, which is more conducive to the control of aberration and further improves the overall reliability of the system.

[0048] In addition, as described above, by optimizing the parameter design of each optical component of the optical system, the present invention can achieve imaging within a wide spectral range of 200 nm to 900 m, and can achieve high-quality optical imaging effects on the basis of ensuring miniaturization and light weight.

[0049] 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 manners. Any other implementation manners obtained 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) 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 entrance 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 detecting portion (8); 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 all off-axis concave reflecting mirrors; The light beam converged by the first convergent portion (1) passes through a material sample, and the material 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 convergent 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). After the light beam is split, the light beam passes through the second concave reflector (7) and is finally detected by the detection portion (8). The optical power of the second reflecting part is Φ 57， The focal length 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 unit (8) is L, which satisfies the following relationship: 3.3≤L1 / L≤4.

5.

2. The material detection optical system according to claim 1, characterized in that: The first converging portion (1) is capable of converging a light beam emitted by a laser and incident on a 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 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.

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

4. The material detection optical system according to claim 1, characterized in that: 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.

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

02.

6. The material detection optical system according to claim 1, characterized in that: 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.

7. The material detection optical system according to claim 1, characterized in that: 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°.

8. The material detection optical system according to any one of claims 1 to 7, characterized in that: 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°≤θ4≤85°, and -28≤Y2≤-20.

9. The material detection optical system according to any one of claims 1 to 7, characterized in that: 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.

10. The material detection optical system according to any one of claims 1 to 7, characterized in that: The first concave reflector (5), the blazed grating (6), and the second concave reflector (7), along the light propagation direction, 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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