High-resolution scanning spectrometer based on linear array detector and use method

Abstract

The invention discloses a high-resolution scanning spectrometer based on a linear array detector and a use method, and belongs to the technical field of spectrum instruments and spectral analysis. The first aspherical mirror is used for reducing the diameter of a light beam emitted by the light source, and the second aspherical mirror is used for collimating effective wave band light passing through the slit into parallel light beams; the plane scribed grating is used for diffracting the light beam; the reflection system is used for reflecting the light beam to enable the light beam to enter the plane scribed grating again for secondary diffraction; the first spherical mirror is used for collimating light beams passing through the first aspherical mirror, the second spherical mirror is used for converging the light beams diffracted for the first time at the slit, and the third spherical mirror is used for converging the light beams diffracted for the second time into the linear array photoelectric detector. The advantages of a light splitting type spectrograph and a scanning type spectrograph are combined, a reflection type light path structure is adopted, extra aberration introduced by a transmission type light path is avoided, the data acquisition efficiency is improved, and high-quality imaging is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of spectral instruments and spectral analysis, and in particular to a high-resolution scanning spectrometer based on a linear array detector and a method for using the same. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Spectrometers have been widely used in various fields, such as chemical composition analysis, material property analysis, molecular structure research, etc. With the continuous development of technology, people have higher and higher requirements for the resolution of spectral interrogators. As portable spectrometers gradually become mainstream, using fewer optical components to achieve higher spectral resolution has become an urgent need.

[0004] Currently, high-resolution spectrometers are usually required for component analysis or signal demodulation analysis of specific materials. Different types of spectrometers have their own advantages and disadvantages, but existing systems generally face some technical limitations. For example, although spectroscopic spectrometers have good portability, their wavelength range is usually inversely proportional to the resolution, making it difficult to meet the precise requirements for any wavelength in the near-infrared band; cascade spectrometers have complex optical path designs and a large number of components, resulting in a significant increase in cost, and greater difficulty in assembly and positioning; scanning spectrometers have higher resolutions, but they usually rely on photodiodes as detection devices, requiring repeated scanning, resulting in cumbersome operation procedures and low efficiency. Summary of the Invention

[0005] To address the above problems, the present invention proposes a high-resolution scanning spectrometer based on a linear array detector and a method for use. Combining the advantages of spectroscopic and scanning spectrometers, the efficiency of data acquisition is improved while ensuring a high resolution. The reflective optical path structure is adopted to effectively avoid the additional aberrations introduced by the transmissive optical path, thereby ensuring high-quality imaging of the optical system.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A first aspect of the present invention provides a high-resolution scanning spectrometer based on a linear array detector, comprising: a light source for emitting a light beam; An aspheric mirror, comprising a first aspheric mirror and a second aspheric mirror, wherein the first aspheric mirror is used to reduce the diameter of a light beam emitted by a light source and transmit the light beam to the first spherical mirror, and the second aspheric mirror is used to collimate the effective wavelength band light passing through the slit into a parallel light beam and transmit the parallel light beam to the reflection system; A planar ruled grating, used to diffract a light beam; A reflection system, used to reflect the light beam so that it re-enters the plane ruled grating for secondary diffraction; The spherical mirror includes a first spherical mirror, a second spherical mirror and a third spherical mirror. The first spherical mirror is used to collimate the light beam passing through the first aspherical mirror and transmit the light beam to the plane ruled grating. The second spherical mirror is used to converge the light beam after the first diffraction at the slit. The third spherical mirror is used to converge the light beam after the second diffraction into the linear array photodetector.

[0007] As a further implementation manner, the slit is located between the second spherical mirror and the second aspherical mirror, so as to block light beams of non-effective wavelengths.

[0008] As a further implementation, the planar ruled grating receives the parallel light beam passing through the first spherical mirror, undergoes a first diffraction, and receives the light beam reflected by the reflection system, undergoes a second diffraction.

[0009] As a further implementation method, the light beam after the second diffraction is converged by a third spherical mirror and enters the linear array photodetector.

[0010] As a further implementation method, the reflection system includes multiple mirrors, which are placed at different positions of the spectrometer system to reflect the light beam passing through the second aspherical mirror, causing it to re-enter the plane ruled grating and undergo secondary diffraction.

[0011] As a further implementation, the first aspherical mirror may be omitted from the spectrometer system.

[0012] As a further implementation, the reflection system includes a first reflection mirror, a second reflection mirror, and a third reflection mirror.

[0013] As a further implementation manner, the light beam passing through the first spherical mirror and the reflection system is incident on the plane ruled grating at a certain angle.

[0014] As a further implementation, a linear array photodetector is used to convert the optical signal into an electrical signal.

[0015] A second aspect of the present invention provides a method for using a high-resolution scanning spectrometer based on a linear array detector, the method comprising the following steps: The light beam emitted by the light source is incident on the first spherical mirror after the diameter of the light beam is reduced by the first aspherical mirror; After being collimated by the first spherical mirror, the light beam is transformed into parallel light and incident on the plane ruled grating at a certain angle, and the light beam undergoes the first diffraction; The light beam after the first diffraction is incident on the second spherical mirror, which makes the light beam after the first diffraction converge at the slit; The effective wavelength light passing through the slit is re-collimated into a parallel beam by the second aspheric mirror, reflected by the reflection system, and re-enters the plane ruled grating to undergo secondary diffraction; The light beam after the second diffraction is converged by the third spherical mirror and enters the linear array photoelectric detector, which converts the optical signal into an electrical signal.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The high-resolution scanning spectrometer based on a linear array detector and its use method of the present invention combine the advantages of both spectroscopic and scanning spectrometers and have significant advantages through the following innovative designs: 1. It makes up for the low resolution defect of the spectrometer while maintaining a small optical path volume.

[0017] By employing a single grating and subjecting it to double diffraction, the spectrometer's resolution is further improved. Furthermore, rational optical parameter calculation and device selection not only reduce costs but also compress the optical path volume. This invention inherits the advantages of scanning spectrometers and, through rational optical design, ensures a high resolution.

[0018] 2. The scanning spectrometer has been simplified to address the more tedious steps in the secondary small-area scanning.

[0019] In general, the first scan of a traditional scanning spectrometer has a larger spectral range, and the second scan will be more targeted to observe a certain peak for specific observation. The present invention takes advantage of the advantages of a spectroscopic spectrometer and uses a linear array detector to collect spectral data of the entire small band at one time, greatly improving the efficiency of data acquisition and avoiding the tedious steps of repeated scanning.

[0020] 3. Solved the aberration problem caused by transmissive optical elements.

[0021] By adopting a reflective optical path structure, the generation of aberrations is effectively reduced, the design of the optical path is optimized, and the imaging quality and portability of the spectrometer are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0023] Figure 1 This is a diagram of the cross CT optical path structure of the spectrometer; Figure 2This is the optical path structure diagram of the cascade spectrometer; Figure 3 This is the optical path structure diagram of the scanning spectrometer; Figure 4 This is a light path simulation diagram of the high-resolution scanning spectrum based on the linear array detector of the present invention; Figure 5 Schematic diagram of the optical path replacement structure of the high-resolution scanning spectroscopy based on the linear array detector of the present invention.

[0024] Among them, 1-1, light source; 1-2, collimator; 1-3, plane blazed grating; 1-4, converging lens; 1-5, linear array CCD chip; 2-1, light source; 2-2, concave reflector; 2-3, plane reflection grating; 2-4, plane reflector; 2-5, slit; 2-6, linear array CCD chip; 3-1, light source; 3-2, collimator; 3-3, plane reflection grating; 3-4, converging lens; 3-5, slit; 3-6, photodiode; 4-1, light source; 4-2, first aspheric mirror; 4-3, first spherical mirror; 4-4, plane ruled grating; 4-5, second spherical mirror; 4-6, slit; 4-7, second aspheric mirror; 4-8, first reflector; 4-9, second reflector; 4-10, third reflector; 4-11, third spherical mirror; 4-12, linear array photodetector; 5-1. Light source; 5-2. First spherical mirror; 5-3. Plane ruled grating; 5-4. Second spherical mirror; 5-5. Slit; 5-6. Aspherical mirror; 5-7. First reflecting mirror; 5-8. Second reflecting mirror; 5-9. Third reflecting mirror; 5-10. Third spherical mirror; 5-11. Linear array photodetector. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0027] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0028] Example 1 Spectrometers in the prior art include spectroscopic spectrometers, cascade spectrometers, and photodiode-based scanning spectrometers. The following is a detailed description of these spectrometers: Spectrometer: At present, the technology of spectrometer is relatively mature, usually using a cross-type optical path structure. Through high-dispersion optical elements, the optical path volume is greatly reduced and multiple bands can be analyzed at one time, with a faster processing speed. However, when a larger wavelength range needs to be covered, its resolution is low. It is difficult to meet the needs of more accurate measurements. Figure 1 The figure shows the basic principle of the optical path of a spectrometer.

[0029] Spectrometers have the advantages of small size, simple structure, and high flexibility. However, when covering a large wavelength band, the resolution is poor and cannot meet existing needs. The details are as follows: 1) In the near-infrared band, although its size is small, its resolution is lower than that of a scanning spectrometer, making it difficult to meet existing application requirements.

[0030] 2) The wavelength range of the spectrometer at high resolution is limited, and as the wavelength range increases, the resolution of the spectrometer tends to decrease.

[0031] Cascade spectrometer: like Figure 2 As shown in Figure 1, cascaded spectrometers improve the system's signal-to-noise ratio and sensitivity by connecting multiple spectrometers in cascade. They can also cover a wider wavelength range, making them suitable for analyzing complex samples. Cascaded systems can precisely adjust and optimize signals through the combination of multiple spectrometers, making them suitable for applications requiring high sensitivity and wide-band analysis.

[0032] Although cascade spectrometers offer high performance, they have some inherent drawbacks due to their complex optical design. These include: 1) Cascade spectrometers typically contain multiple optical components, increasing system complexity and weight, significantly increasing spectrometer cost. Furthermore, the large number of components complicates assembly and positioning, impacting production efficiency.

[0033] 2) The use of multiple optical elements easily introduces multiple reflections and refractions, which increases aberrations. This affects the imaging quality and measurement accuracy of the system, and increases the difficulty of optical system design and debugging.

[0034] Scanning spectrometers based on photodiodes: like Figure 3 As shown in the figure, a scanning spectrometer employs a simple optical structure and uses a photodiode as a detector, providing high resolution and suitable for measurement needs across a wide range of wavelengths. Its operating principle typically relies on a scanning process, where the detector gradually collects spectral data at different wavelengths. However, when multiple measurements of spectra within a small wavelength range are required, the operation becomes cumbersome and inefficient.

[0035] Although scanning spectrometers have significant advantages in terms of resolution, they also have operational shortcomings. The specific problems are as follows: 1) Due to the use of a single-point detector, rescanning is required after each scan when measuring a small wavelength range spectrum. This makes the measurement steps cumbersome, wastes time, and significantly reduces the overall detection efficiency.

[0036] 2) Repeated scanning may cause a certain time delay, affecting the working efficiency of the equipment, especially in experiments that require rapid data acquisition.

[0037] 3) In order to reduce the volume, a transmissive optical path is generally used, but this will introduce additional aberrations, resulting in a significant reduction in resolution.

[0038] To address these issues, the present invention's high-resolution scanning spectrometer, based on a linear array detector, combines the advantages of both spectroscopic and scanning spectrometers, achieving "one-time acquisition" of high-resolution data within a small wavelength range. This solution effectively addresses many of the existing issues, specifically in the following aspects: (1) Taking advantage of the spectrometer, a linear array detector is used, which enables it to obtain all relevant data at one time within a small waveband range, thereby improving the efficiency of data acquisition.

[0039] (2) The reflective optical path structure is adopted to effectively avoid the additional aberration introduced by the transmissive optical path, ensuring high-quality imaging of the optical system.

[0040] (3) It inherits the advantages of scanning spectrometers and ensures high resolution through reasonable optical design.

[0041] The solution of the present invention is explained in detail below.

[0042] like Figure 4 As shown, this embodiment provides a high-resolution scanning spectrometer based on a linear array detector, including a light source 4-1, a first aspheric mirror 4-2, a first spherical mirror 4-3, a plane ruled grating 4-4, a second spherical mirror 4-5, a slit 4-6, a second aspheric mirror 4-7, a first reflector 4-8, a second reflector 4-9, a third reflector 4-10, a third spherical mirror 4-11 and a linear array photodetector 4-12, which are arranged in sequence along the propagation direction of the light path.

[0043] Among them, the light source 4-1 is used to emit a light beam.

[0044] The first aspheric mirror 4-2 is located between the light source 4-1 and the first spherical mirror 4-3, and is used to reduce the diameter of the light beam emitted by the light source 4-1 and transmit the light beam to the first spherical mirror 4-3. The beam diameter is reduced by the first aspheric mirror 4-2 so that the small-sized grating can still receive the entire beam, avoiding light loss.

[0045] The first spherical mirror 4-3 is used to collimate the light beam passing through the first aspherical mirror 4-2 and transmit the light beam to the planar ruled grating 4-4. The divergent light beam is collimated by the first spherical mirror 4-3 and converted into parallel light, which is incident on the planar ruled grating 4-4 ​​at a certain angle. At this time, the light beam undergoes the first diffraction.

[0046] The ruled grating 4-4 ​​is used to diffract the light beam. In the present invention, the light beam is diffracted twice by the ruled grating 4-4: the first diffraction occurs when the ruled grating 4-4 ​​receives the parallel light beam that has passed through the first spherical mirror 4-3; and the second diffraction occurs when the ruled grating 4-4 ​​receives the light beam reflected by the reflection system. The light beam that has passed through the first spherical mirror 4-3 and the reflection system is incident on the ruled grating 4-4 ​​at a certain angle.

[0047] The second spherical mirror 4-5 is used to make the light beam after the first diffraction by the plane ruled grating 4-4 ​​converge at the slit 4-6. The slit 4-6 is located between the second spherical mirror 4-5 and the second aspherical mirror 4-7 and is used to block light beams of non-effective wavelengths.

[0048] The second aspheric mirror 4-7 is used to collimate the effective wavelength band light passing through the slit 4-6 into a parallel light beam and transmit it to the reflection system.

[0049] The reflection system is used to reflect the light beam so that it re-enters the planar ruled grating 4-4 ​​for secondary diffraction. The reflection system includes multiple reflectors, which are placed at different positions in the spectrometer system. The reflectors reflect the light beam that passes through the second aspheric mirror 4-7 so that it re-enters the planar ruled grating 4-4 ​​for secondary diffraction. The reflection system includes a first reflector 4-8, a second reflector 4-9, and a third reflector 4-10.

[0050] The third spherical mirror 4-11 is used to converge the light beam after the second diffraction into the linear array photodetector 4-12, and the linear array photodetector 4-12 is used to convert the optical signal into an electrical signal.

[0051] The spectrometer of the present invention adopts a reflective structure as a whole, which avoids large aberrations and only requires a single grating to perform two diffractions, which can effectively improve the optical resolution and ultimately transmit a wavelength beam in a small band range to the linear array detector.

[0052] like Figure 5As shown, in the optical components of the high-resolution scanning spectrometer based on the linear array detector of the present invention, the following can be substituted: The first aspheric lens 4-2 behind the light source can be removed. In this application, the first aspheric lens 4-2 is mainly used to adjust the beam diameter and reduce light loss. If a large-scale grating and other optical components are used in the system, the aspheric lens can be removed to optimize cost and structural design.

[0053] Example 2 This embodiment provides a method for using a high-resolution scanning spectrometer based on a linear array detector, which is based on the high-resolution scanning spectrometer based on a linear array detector in Embodiment 1 and includes the following steps: The light beam emitted by the light source is incident on the first spherical mirror after the diameter of the light beam is reduced by the first aspherical mirror; After being collimated by the first spherical mirror, the light beam is transformed into parallel light and incident on the plane ruled grating at a certain angle, and the light beam undergoes the first diffraction; The light beam after the first diffraction is incident on the second spherical mirror, which makes the light beam after the first diffraction converge at the slit; The effective wavelength light passing through the slit is re-collimated into a parallel beam by the second aspheric mirror, reflected by the reflection system, and re-enters the plane ruled grating to undergo secondary diffraction; The light beam after the second diffraction is converged by the third spherical mirror and enters the linear array photoelectric detector, which converts the optical signal into an electrical signal.

[0054] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

[0055] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A high-resolution scanning spectrometer based on a linear array detector, characterized in that: include: a light source for emitting a light beam; An aspheric mirror, comprising a first aspheric mirror and a second aspheric mirror, wherein the first aspheric mirror is used to reduce the diameter of a light beam emitted by a light source and transmit the light beam to the first spherical mirror, and the second aspheric mirror is used to collimate the effective wavelength band light passing through the slit into a parallel light beam and transmit the parallel light beam to the reflection system; A planar ruled grating, used to diffract a light beam; A reflection system, used to reflect the light beam so that it re-enters the plane ruled grating for secondary diffraction; The spherical mirror includes a first spherical mirror, a second spherical mirror and a third spherical mirror. The first spherical mirror is used to collimate the light beam passing through the first aspherical mirror and transmit the light beam to the plane ruled grating. The second spherical mirror is used to converge the light beam after the first diffraction at the slit. The third spherical mirror is used to converge the light beam after the second diffraction into the linear array photodetector.

2. The high-resolution scanning spectrometer based on a linear array detector according to claim 1, characterized in that: The slit is located between the second spherical mirror and the second aspherical mirror, and is used to block light beams with non-effective wavelengths.

3. The high-resolution scanning spectrometer based on a linear array detector according to claim 1, wherein: The plane ruled grating receives the parallel light beam passing through the first spherical mirror and undergoes a first diffraction, and receives the light beam reflected by the reflection system and undergoes a second diffraction.

4. The high-resolution scanning spectrometer based on a linear array detector according to claim 3, wherein: The light beam after the second diffraction is converged by the third spherical mirror and enters the linear array photodetector.

5. The high-resolution scanning spectrometer based on a linear array detector according to claim 1, wherein: The reflection system includes multiple reflecting mirrors, which are placed at different positions of the spectrometer system to reflect the light beam passing through the second aspherical mirror, so that the light beam re-enters the plane ruled grating and undergoes secondary diffraction.

6. The high-resolution scanning spectrometer based on a linear array detector according to claim 1, wherein: The first aspherical mirror can be omitted in the spectrometer system.

7. The high-resolution scanning spectrometer based on a linear array detector according to claim 5, characterized in that: The reflection system includes a first reflection mirror, a second reflection mirror and a third reflection mirror.

8. The high-resolution scanning spectrometer based on a linear array detector according to claim 1, wherein: The light beam passing through the first spherical mirror and the reflection system is incident on the plane ruled grating at a certain angle.

9. The high-resolution scanning spectrometer based on a linear array detector according to claim 1, wherein: The linear array photoelectric detector is used to convert optical signals into electrical signals.

10. A method for using a high-resolution scanning spectrometer based on a linear array detector, characterized in that: The high-resolution scanning spectrometer based on a linear array detector according to any one of claims 1 to 9 comprises the following steps: The light beam emitted by the light source is incident on the first spherical mirror after the diameter of the light beam is reduced by the first aspherical mirror; After being collimated by the first spherical mirror, the light beam is transformed into parallel light and incident on the plane ruled grating at a certain angle, and the light beam undergoes the first diffraction; The light beam after the first diffraction is incident on the second spherical mirror, which makes the light beam after the first diffraction converge at the slit; The effective wavelength light passing through the slit is re-collimated into a parallel beam by the second aspheric mirror, reflected by the reflection system, and re-enters the plane ruled grating to undergo secondary diffraction; The light beam after the second diffraction is converged by the third spherical mirror and enters the linear array photoelectric detector, which converts the optical signal into an electrical signal.

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