Fourier transform spectrometer system of multiband light source structure

Abstract

The invention discloses a Fourier transform spectrometer system of a multiband light source structure, which comprises a multiband light source conveying unit used for transmitting light of multiple bands; the collimation unit is used for collimating the light transmitted by the multiband light source conveying unit; the light beam combining unit is used for forming a combined light beam; the light splitting unit is used for respectively transmitting and reflecting the plurality of beams of light; the reflector unit is used for receiving the multiple beams of light transmitted or reflected by the light splitting unit and retroreflecting the multiple beams of light in the incident direction of the multiple beams of light; and the detection unit is used for converging the multiple beams of light reflected by the reflector unit and receiving and detecting the converged multiple beams of light. According to the invention, input wavebands can be selected and multiple wavebands can be measured simultaneously, and near-infrared light and far-infrared light can be measured simultaneously, so that the detection efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of spectral analysis technology, specifically a Fourier transform spectrometer system with a multi-band light source structure. Background Technology

[0002] Fourier transform spectrometers are widely used in material composition analysis, and multi-band measurements can improve detection accuracy and efficiency. Traditional multi-band spectrometers typically use motor-driven switching of light sources in different bands, such as alternating between near-infrared and far-infrared light by mechanically moving mirrors or filters. This switching method has the following problems: motor switching introduces mechanical vibration and wear, leading to repeatability errors and affecting measurement stability; the switching process is time-consuming, making true simultaneous measurement impossible and limiting real-time applications; the structure is complex, and the bandwidth is limited, making it difficult to cover wide-band requirements.

[0003] Therefore, a light source structure that can couple multiple wavelengths of light simultaneously without the need for motor switching is needed to improve stability, eliminate errors, and expand the measurable wavelength. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, embodiments of the present invention provide a Fourier transform spectrometer system with a multi-band light source structure, which is used to solve one or more of the above-mentioned problems.

[0005] This application discloses a Fourier transform spectrometer system with a multi-band light source structure, comprising: a multi-band light source transmission unit for transmitting light of multiple bands; a collimation unit located at the rear end of the multi-band light source transmission unit for collimating the light transmitted by the multi-band light source transmission unit; a beam combining unit located at the rear end of the collimation unit for combining the multiple light segments collimated by the collimation unit into a single optical path to form a composite beam; and a beam splitting unit located at... At the rear end of the beam combining unit, the beam splitting unit is used to split the composite beam into multiple beams, and to transmit and reflect the multiple beams respectively; the reflector unit, located at the rear end of the beam combining unit, is used to receive the multiple beams transmitted or reflected by the beam splitting unit, and to reflect the multiple beams back along their incident direction; the detection unit, located at the rear end of the reflector unit, is used to combine the multiple beams reflected back by the reflector unit, and to receive and detect the combined multiple beams.

[0006] Furthermore, the beam combining unit includes a beam combiner, the two sides of which are used to transmit and reflect multiple light segments after collimation by the collimation unit, so as to combine the multiple light segments transmitted or reflected by the beam combiner into a single optical path.

[0007] Furthermore, the multi-band light source transmission unit includes a first single-core optical fiber and a second single-core optical fiber that are isolated from each other, and the first single-core optical fiber and the second single-core optical fiber are used to transmit light of different bands respectively.

[0008] Furthermore, the collimation unit includes a collimating lens disposed between the output end of the first single-core fiber and the combiner. The collimating lens is used to collimate the light rays of the first single-core fiber and transmit the collimated light rays to the transmission surface of the combiner.

[0009] Furthermore, the collimation unit also includes a first gold-plated off-axis parabolic mirror disposed between the second single-core optical fiber and the combiner. The first gold-plated off-axis parabolic mirror is used to collimate the light from the second single-core optical fiber and deliver the collimated light to the reflecting surface of the combiner.

[0010] Furthermore, the beam splitting unit includes a beam splitter disposed at the output end of the beam combining unit. The beam splitter is used to split the composite beam into a transmission beam and a reflection beam. The beam splitter can transmit the transmission beam, and the reflection beam can reflect the reflection beam.

[0011] Furthermore, the reflector unit includes a first hollow retroreflector and a second hollow retroreflector respectively disposed corresponding to the reflected beam and the transmitted beam. The first hollow retroreflector is used to return the reflected beam along the original path, and the second hollow retroreflector is used to return the transmitted beam along the original path. The reflected light reflected by the first hollow retroreflector is transmitted by the beam splitter, and the transmitted beam transmitted by the second hollow retroreflector is reflected by the beam splitter, so that the two optical fibers merge to form a merged beam.

[0012] Furthermore, the first hollow retroreflector is mounted on a fixed base, and the second hollow retroreflector is mounted on an elastic pivot, the elastic pivot being pivotally connected to the fixed base.

[0013] Furthermore, the detection unit includes a second gold-plated off-axis parabolic mirror disposed on one side of the beam splitter's output end. The second gold-plated off-axis parabolic mirror is used to focus the converging beam to form an interference light signal.

[0014] Furthermore, the detection unit also includes a detector disposed at the exit end of the second gold-plated off-axis parabolic mirror, the detector being used to receive the interference light signal and convert the interference light signal into an interferogram electrical signal containing information of all wavebands.

[0015] The beneficial effects of this invention are as follows: 1. It can simultaneously select input bands and measure multiple bands at the same time. Near-infrared and far-infrared light can be measured simultaneously, thereby improving detection efficiency.

[0016] 2. By using a beam combiner, near-infrared and far-infrared light are coupled simultaneously, thereby avoiding the mechanical switching of motors in existing technologies, improving the stability of simultaneous multi-band measurements, and extending service life.

[0017] 3. The overall structure is compact, and the optical path formed by the reflector unit is permanently collimated by the hollow retroreflector, thereby eliminating repeatability errors.

[0018] 4. It has a wide measurable band, making it suitable for scenarios involving analysis of a broad spectral range.

[0019] 5. Two hollow retroreflectors are respectively mounted on a fixed base and an elastic pivot, allowing the angle between the two hollow retroreflectors to vary, thereby ensuring the stability and alignment accuracy of the optical path.

[0020] To make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a Fourier transform spectrometer system with a multi-band light source structure according to an embodiment of the present invention; Figure 2 This is a planar structural diagram of a Fourier transform spectrometer system with a multi-band light source structure according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the optical path of a Fourier transform spectrometer system with a multi-band light source structure according to an embodiment of the present invention; The reference numerals in the above figures are as follows: 1. Multi-band light source transmission unit; 11. First single-core optical fiber; 12. Second single-core optical fiber; 2. Collimation unit; 21. Collimating mirror; 22. First gold-plated off-axis parabolic mirror; 3. Beam combining unit; 31. Beam combiner; 4. Beam splitting unit; 41. Beam splitter; 5. Reflector unit; 51. First hollow retroreflector; 52. Second hollow retroreflector; 53. Fixing base; 54. Elastic pivot; 6. Detection unit; 61. Second gold-plated off-axis parabolic mirror; 62. Detector. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] like Figures 1 to 3 The Fourier transform spectrometer system shown has a multi-band light source structure, comprising: A multi-band light source transmission unit 1 is used to transmit light of multiple wavelengths. In this embodiment, the multi-band light source transmission unit 1 includes a first single-core optical fiber 11 and a second single-core optical fiber 12 that are isolated from each other. The first single-core optical fiber 11 and the second single-core optical fiber 12 are used to transmit light of different wavelengths, specifically near-infrared and far-infrared light. Of course, in other optional embodiments, the type of light can be adjusted according to actual needs. Preferably, the second single-core optical fiber 12 is located below the first single-core optical fiber 11, and the first single-core optical fiber 11 and the second single-core optical fiber 12 are used to introduce optical signals from the outside into the system.

[0025] Collimation unit 2 is located at the rear end of the multi-band light source transmission unit 1 and is used to collimate the light transmitted by the multi-band light source transmission unit 1, so that the collimation unit 2 can achieve the collimation effect on all the light emitted by the multi-band light source transmission unit 1.

[0026] The collimation unit 2 may include a collimating lens 21 disposed between the emitting end of the first single-core optical fiber 11 and the combiner 31. The collimating lens 21 is used to collimate the light from the first single-core optical fiber 11 and transmit the collimated light to the transmission surface of the combiner 31.

[0027] The collimation unit 2 may further include a first gold-plated off-axis parabolic mirror 22 disposed between the second single-core optical fiber 12 and the combiner 31. The first gold-plated off-axis parabolic mirror 22 is used to collimate the light from the second single-core optical fiber 12 and transmit the collimated light to the reflecting surface of the combiner 31.

[0028] A beam combining unit 3 is located at the rear end of the collimating unit 2. The beam combining unit 3 combines multiple light rays collimated by the collimating unit 2 into a single optical path to form a composite beam. Different collimated light rays are incident on the beam combining unit 3 at specific angles. The beam combining unit 3 can have specific transmittance and reflectivity for different light rays, thereby combining light from different light sources and different wavelengths into a common optical path.

[0029] The beam combining unit 3 includes a beam combiner 31. The beam combiner 31, based on its coating characteristics, has specific transmittance and reflectivity for near-infrared and far-infrared light bands, respectively. The two sides of the beam combiner 31 are used to transmit and reflect multiple light segments collimated by the collimating unit 2, respectively, so as to combine the multiple light segments transmitted or reflected by the beam combiner 31 into a single optical path. Preferably, the beam combiner 31 is a semi-transparent, semi-reflective beam splitter.

[0030] Beam splitting unit 4 is located at the rear end of beam combining unit 3. Beam splitting unit 4 is used to split the composite beam into multiple beams and to transmit and reflect the multiple beams respectively. Beam splitting unit 4 can achieve the effect of transmitting and reflecting the multiple beams respectively based on the different transmission and reflection effects of different beams.

[0031] The beam splitting unit 4 includes a beam splitter 41 disposed at the output end of the beam combining unit 3. The beam splitter 41 is used to split the composite beam into a transmission beam and a reflection beam. The beam splitter 41 can transmit the transmission beam, and the reflector can reflect the reflection beam.

[0032] The reflector unit 5 is located at the rear end of the beam combining unit 3. The reflector unit 5 is used to receive the multiple beams of light transmitted or reflected by the beam splitting unit 4 and reflect the multiple beams of light back along their incident direction.

[0033] Specifically, the reflector unit 5 includes a first hollow retroreflector 51 and a second hollow retroreflector 52, respectively disposed corresponding to the reflected beam and the transmitted beam. Due to the optical characteristics of the hollow retroreflector, regardless of the angle from which the light is incident, the outgoing light will return strictly in a direction parallel to the incident light. This characteristic makes the system insensitive to small angular deviations, greatly enhancing stability. Thus, the first hollow retroreflector 51 can be used to return the reflected beam along its original path, and the second hollow retroreflector 52 can be used to return the transmitted beam along its original path, so that both the reflected beam via the first hollow retroreflector 51 and the transmitted beam via the second hollow retroreflector 52 can be reflected and returned to the beam splitter 41.

[0034] The reflected light beam, after being reflected by the first hollow retroreflector 51, is transmitted through the beam splitter 41, and the transmitted light beam, after being transmitted through the second hollow retroreflector 52, is reflected by the beam splitter 41, so that the two optical fibers merge to form a merged beam, thereby making the formed merged beam completely parallel.

[0035] Specifically, the first hollow retroreflector 51 is mounted on the fixed base 53, and the second hollow retroreflector 52 is mounted on the elastic pivot 54, which is pivotally connected to the fixed base 53. This allows the second hollow retroreflector 52 to be connected to the fixed base 53 via the elastic pivot 54. Since the elastic pivot 54 is a frictionless, flexible support structure, the first hollow retroreflector 51 and the second hollow retroreflector 52 can be connected as a whole via the fixed base 53, performing high-precision circular reciprocating motion along the elastic pivot 54 under the drive of a voice coil motor, thereby accurately and stably introducing a continuously changing optical path difference.

[0036] The detection unit 6 is located at the rear end of the reflector unit 5. The detection unit 6 is used to combine multiple beams of light reflected back by the reflector unit 5 and to receive and detect the combined beams of light.

[0037] Specifically, the detection unit 6 includes a second gold-plated off-axis parabolic mirror 61 disposed on one side of the output end of the beam splitter 41. The second gold-plated off-axis parabolic mirror 61 is used to focus the converging beam to form an interference light signal. It is worth noting that the gold-plated off-axis parabolic mirror has two key characteristics: "off-axis" avoids central obstruction, ensuring light throughput; "gold plating" ensures extremely high reflectivity in a wide wavelength range, especially in the far-infrared band. The function of the second gold-plated off-axis parabolic mirror 61 is to accurately focus parallel light. The function of the first gold-plated off-axis parabolic mirror 22 is to convert the light transmitted by the second single-core optical fiber 12 into parallel light.

[0038] Specifically, the detection unit 6 further includes a detector 62 disposed at the exit end of the second gold-plated off-axis parabolic mirror 61. The detector 62 is used to receive the interference light signal and convert it into an interferogram electrical signal containing information of all wavebands, so that the two beams of light returned by the first hollow retroreflector 51 and the second hollow retroreflector 52 can be re-entered by the beam splitter 41 and interfere to form an interference light signal. This signal is received by the detector 62 and converted into an interferogram electrical signal containing information of all wavebands, which is then used by the subsequent data processing system to perform a Fourier transform and finally reconstruct the spectrum of the sample.

[0039] In this embodiment, near-infrared and far-infrared light carrying sample information are emitted from the first single-core optical fiber 11 and the second single-core optical fiber 12, respectively. The light emitted from the first single-core optical fiber 11 is collimated into parallel light by the collimating lens 21. The light emitted from the second single-core optical fiber 12 is collimated into parallel light by the first gold-plated off-axis parabolic mirror 22. This structure serves as the foundation of the entire system, ensuring that the light waves enter the combiner 31 in plane wave form, thus reducing errors.

[0040] Next, the two parallel beams are incident on the combiner 31. The light emitted from the first single-core fiber 11 is collimated and transmitted to the transmission surface of the combiner 31, while the light emitted from the second single-core fiber 12 is collimated and transmitted to the reflection surface of the combiner 31. The combiner 31 can be a semi-transparent, semi-reflective beam splitter, characterized by specific transmittance / reflectance for near-infrared light (e.g., 50 / 50) and also specific transmittance / reflectance for far-infrared light. The combiner 31 can "fold" the optical paths of the near-infrared and far-infrared bands together, combining them into a single beam containing multi-band information, thus forming a composite beam. This is crucial for achieving simultaneous measurement without switching.

[0041] Next, the composite beam is incident on beam splitter 41. This is the core component of the Fourier interferometer. Beam splitter 41 splits the incident composite beam into two beams of approximately equal intensity. One beam is transmitted, forming the transmission beam; the other beam is reflected, forming the reflection beam.

[0042] Next, the reflected beam and the transmitted beam are received by the first hollow retroreflector 51 and the second hollow retroreflector 52, respectively, and returned along their original paths. The hollow retroreflector typically consists of three mutually perpendicular reflecting surfaces, such as a corner cube prism. A characteristic of the hollow retroreflector is that regardless of the angle from which the light enters, the outgoing light will return strictly parallel to the incident light. This characteristic makes its tolerance for installation angles far superior to that of a plane mirror, greatly improving the system's stability and anti-interference capability. The first hollow retroreflector 51 is mounted on the fixed base 53, serving as a fixed mirror; the second hollow retroreflector 52 is mounted on an elastic pivot 54, connecting the second hollow retroreflector 52 to the fixed base 53 via the elastic pivot 54. It can act as a moving mirror, undergoing minute linear reciprocating motion, thereby introducing a continuously varying optical path difference.

[0043] Next, the two beams of light returning from the first hollow retroreflector 51 and the second hollow retroreflector 52 are combined into interference light after passing through the second gold-plated off-axis parabolic mirror 61, and enter the detector 62, thus allowing the interference light to be received by the detector 62. During this process, due to the movement of the elastic pivot 54, the optical path difference changes continuously, and the detector 62 records the signal of the interference light intensity changing with the optical path difference, i.e., the interferogram. The detector 62 receives the interference light signal and converts it into an interferogram electrical signal containing information of all wavebands.

[0044] With the above structure, this solution has the following advantages: 1. It can simultaneously select input bands and measure multiple bands at the same time. Near-infrared and far-infrared light can be measured simultaneously, thereby improving detection efficiency.

[0045] 2. Using a beam combiner 31, near-infrared and far-infrared light are coupled simultaneously, thereby avoiding the mechanical switching of the motor in the prior art, improving the stability of simultaneous multi-band measurement, and extending the service life.

[0046] 3. The overall structure is compact, and the optical path formed by the reflector unit 5 is permanently collimated by the hollow retroreflector, thereby eliminating repeatability errors.

[0047] 4. It has a wide measurable band, making it suitable for scenarios involving analysis of a broad spectral range.

[0048] 5. Two hollow retroreflectors are respectively mounted on the fixed base 53 and the elastic pivot 54, so that the angle between the two hollow retroreflectors can be changed, thereby ensuring the stability and alignment accuracy of the optical path.

[0049] Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A Fourier transform spectrometer system with a multi-band light source structure, characterized in that, include: A multi-band light source transmission unit, wherein the multi-band light source transmission unit is used to transmit light of multiple bands; A collimation unit is located at the rear end of the multi-band light source delivery unit and is used to collimate the light transmitted by the multi-band light source delivery unit. A beam combining unit is located at the rear end of the collimating unit. The beam combining unit is used to combine multiple light rays collimated by the collimating unit into the same optical path to form a composite beam. A beam splitting unit is located at the rear end of the beam combining unit. The beam splitting unit is used to split the composite beam into multiple beams and to transmit and reflect the multiple beams respectively. A reflector unit is located at the rear end of the beam combining unit. The reflector unit is used to receive the multiple beams of light transmitted or reflected by the beam splitting unit and to reflect the multiple beams of light back along their incident direction. A detection unit is located at the rear end of the reflector unit. The detection unit is used to combine multiple beams of light reflected back by the reflector unit and to receive and detect the combined beams of light.

2. The Fourier transform spectrometer system with a multi-band light source structure according to claim 1, characterized in that, The beam combining unit includes a beam combiner, with its two sides used to transmit and reflect multiple light segments after they have been collimated by the collimating unit, so as to combine the multiple light segments transmitted or reflected by the beam combiner into a single optical path.

3. The Fourier transform spectrometer system with a multi-band light source structure according to claim 2, characterized in that, The multi-band light source transmission unit includes a first single-core optical fiber and a second single-core optical fiber that are isolated from each other. The first single-core optical fiber and the second single-core optical fiber are used to transmit light in different bands.

4. The Fourier transform spectrometer system with a multi-band light source structure according to claim 3, characterized in that, The collimation unit includes a collimating lens disposed between the output end of the first single-core fiber and the combiner. The collimating lens is used to collimate the light from the first single-core fiber and transmit the collimated light to the transmission surface of the combiner.

5. The Fourier transform spectrometer system with a multi-band light source structure according to claim 4, characterized in that, The collimation unit further includes a first gold-plated off-axis parabolic mirror disposed between the second single-core optical fiber and the combiner. The first gold-plated off-axis parabolic mirror is used to collimate the light from the second single-core optical fiber and to deliver the collimated light to the reflecting surface of the combiner.

6. The Fourier transform spectrometer system with a multi-band light source structure according to claim 1, characterized in that, The beam splitting unit includes a beam splitter disposed at the output end of the beam combining unit. The beam splitter is used to split the composite beam into a transmission beam and a reflection beam. The beam splitter can transmit the transmission beam, and the reflection beam can reflect the reflection beam.

7. The Fourier transform spectrometer system with a multi-band light source structure according to claim 6, characterized in that, The reflector unit includes a first hollow retroreflector and a second hollow retroreflector respectively disposed corresponding to the reflected beam and the transmitted beam. The first hollow retroreflector is used to return the reflected beam along the original path, and the second hollow retroreflector is used to return the transmitted beam along the original path. The reflected light beam, after being reflected by the first hollow retroreflector, is transmitted through the beam splitter, and the transmitted light beam, after being transmitted through the second hollow retroreflector, is reflected by the beam splitter, so that the two optical fibers merge to form a merged beam.

8. The Fourier transform spectrometer system with a multi-band light source structure according to claim 7, characterized in that, The first hollow retroreflector is mounted on a fixed base, and the second hollow retroreflector is mounted on an elastic pivot, which is pivotally connected to the fixed base.

9. A Fourier transform spectrometer system with a multi-band light source structure according to claim 7, characterized in that, The detection unit includes a second gold-plated off-axis parabolic mirror disposed on one side of the beam splitter's output end. The second gold-plated off-axis parabolic mirror is used to focus the converging beam to form an interference light signal.

10. A Fourier transform spectrometer system with a multi-band light source structure according to claim 1, characterized in that, The detection unit further includes a detector disposed at the exit end of the second gold-plated off-axis parabolic mirror. The detector is used to receive the interference light signal and convert the interference light signal into an interferogram electrical signal containing information of all wavebands.

Images