Spectral measurement method and apparatus

Abstract

The invention provides a spectral measurement method and device, and the method comprises the steps: carrying out the spatial superposition of at least two sub-beams in the radial direction of a light beam propagation direction, so as to form a combined light beam; irradiating the combined light beam to a to-be-detected sample to obtain an incident light beam attached with response information of the to-be-detected sample; radial space decoupling beam splitting is carried out based on the incident beam to obtain at least two sub-beams, the spectral information of each sub-beam is measured, the sum of the spectral ranges of the at least two sub-beams continuously covers the target spectral interval, and the spectral ranges of the at least two sub-beams are correspondingly consistent with the spectral ranges of the at least two sub-beams. The problem that there is no method for measuring the spectrum in the ultra-wideband spectrum range in the prior art is solved.

Description

Technical Field

[0001] The present disclosure relates to the field of spectral measurement technologies, and in particular, to a spectral measurement method and device. Background Art

[0002] Spectral measurement and analysis is an important method for studying the composition, structure, and properties of substances through phenomena such as absorption, emission, or scattering of light by substances. Among them, transient spectral measurement and analysis can measure and analyze the spectral changes of substances within an extremely short time, and can reveal the dynamic behavior and physical and chemical properties of substances during the transient process.

[0003] People's requirements for the performance of spectral analysis instruments, such as the measurement acquisition speed and spectral band range, are also getting higher and higher. Traditional spectral measurement methods have some shortcomings in terms of measurement acquisition speed or spectral band range. For example, the band measurement range of a Fourier transform infrared spectrometer can cover from the near-infrared band to the terahertz band, and can perform conventional spectral measurement and transient spectral measurement. However, due to its use of the interference principle, corresponding mechanical components need to move step by step, and the spectral accuracy and acquisition speed restrict each other. It takes more time to perform high-precision GHz-level measurements, and it takes more than a day to perform high-precision time-resolved transient spectral measurements. A Raman spectrometer can achieve fast measurements in seconds based on the principle of inelastic scattering of light, but the measurement band range is in the near-infrared and bands below its wavelength. A terahertz time-domain spectrometer obtains a time-domain signal through optical delay scanning and then obtains spectral information through Fourier transform. The spectral resolution can reach the GHz level, but the mechanical scanning delay method limits the acquisition speed. Spectrometers with gratings or prisms as the core spectral splitting components are limited by the band applicability of the grating or prism itself in terms of material and periodic structure, and it is difficult to achieve ultra-wideband spectral measurement.

[0004] The development of nanophotonics and artificial intelligence has brought about computational spectrometers. First, an incident light is spectrally encoded using a coding mechanism with spectral selection characteristics, and different spectral information is given to the incident light through multiple groups of different codes. Then, a series of encoded light intensity values are obtained through a detector, and the original spectrum is calculated and reconstructed through a machine learning algorithm, which can achieve high-resolution, fast, and real-time measurement of the spectrum. However, currently, it can only be realized within each small band range. For example, a real-time spectral sensing chip based on micro-nano structure metasurface coding and CMOS array detection has a response band that only extends from visible light to near-infrared. In the prior art, when measuring the spectral information of a sample to be measured, a beam with a specific spectral range needs to be input to the sample to be measured. For example, in the case of measuring the full-spectrum spectral information, beams with different band ranges need to be used to irradiate the object to be measured respectively to measure the spectral information of the beams with different band ranges, and finally achieve the purpose of the target spectral measurement range. This takes a long time, the measurement steps are cumbersome, and the measurement accuracy is relatively low.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of clearly and completely explaining the technical solution of the present invention and facilitating the understanding of those skilled in the art. It cannot be considered that the above technical solutions are well-known to those skilled in the art merely because these solutions are described in the background art part of the present invention. Summary of the Invention

[0006] In view of the above problems, the present disclosure provides a spectral measurement method and device, which solves the problem that there is no method for measuring spectra within the ultra-wideband spectral range in the prior art.

[0007] According to a first aspect of the present disclosure, there is provided a spectral measurement method, the method comprising:

[0008] Spatially superposing at least two sub-beams radially along the beam propagation direction to form a combined beam, wherein the sum of the spectral ranges of the at least two sub-beams continuously covers a target spectral interval;

[0009] Irradiating the combined beam onto a sample to be measured to obtain an incident beam with the response information of the sample to be measured;

[0010] Based on the incident beam, performing radial spatial decoupling beam splitting to obtain at least two split beams, wherein the spectral ranges of the at least two split beams respectively correspond to and are consistent with the spectral ranges of the at least two sub-beams;

[0011] Measuring the spectral information of each of the split beams respectively.

[0012] According to an embodiment of the present disclosure, the spatially superposing at least two sub-beams radially along the beam specifically includes:

[0013] Spatially superposing the at least two sub-beams in a coaxial nested structure such that in the combined beam, the at least two sub-beams are distributed radially outward from the beam center along the beam propagation direction.

[0014] According to an embodiment of the present disclosure, the spatially superposing the at least two sub-beams in a coaxial nested structure includes:

[0015] Performing beam reduction and collimation processing on one of the sub-beams to form a reference sub-beam located at the center of the combined beam;

[0016] Performing beam expansion and collimation processing on the remaining sub-beams to form peripheral sub-beams, and arranging the peripheral sub-beams to successively surround the outer periphery of the reference sub-beam.

[0017] According to an embodiment of the present disclosure, the method further includes:

[0018] Focus the combined beam so that the focused combined beam forms a spatial focus at the sample to be measured.

[0019] According to an embodiment of the present disclosure, the method further includes:

[0020] Expand and collimate the incident beam so that the expanded and collimated incident beam can radially spatially decouple and split into at least two sub-beams.

[0021] According to an embodiment of the present disclosure, the radial spatial decoupling and splitting specifically includes:

[0022] Perform a radial reverse separation process on the incident beam with a coaxial nested structure so that the spectral range of each separated sub-beam is consistent with the spectral range of the sub-beam at the corresponding nested position in the combined beam.

[0023] According to an embodiment of the present disclosure, the reference sub-beam is an infrared beam in the near-infrared to far-infrared band, and the method further includes:

[0024] Expand and collimate the sub-beam corresponding to the reference sub-beam to form a reference sub-beam;

[0025] Perform a transmission-reflection splitting process on the reference sub-beam to form a first sub-beam for measuring the near-infrared to mid-infrared band and a second sub-beam for measuring the far-infrared band.

[0026] According to an embodiment of the present disclosure, the peripheral sub-beam is a terahertz beam, and the method further includes:

[0027] Collimate the sub-beam corresponding to the peripheral sub-beam to form a peripheral sub-beam for measuring the terahertz band.

[0028] According to an embodiment of the present disclosure, the method for obtaining the spectral information of each sub-beam specifically includes:

[0029] Perform spectral encoding processing on each sub-beam to generate an encoded beam that matches the spectral range of the corresponding sub-beam and carries spatial phase characteristics;

[0030] Perform identification processing on each encoded beam to obtain the spectral information of each sub-beam.

[0031] According to an embodiment of the present disclosure, the method further includes:

[0032] Perform spectral range screening processing on each sub-beam so that the spectral range of each sub-beam entering the spectral encoding is consistent with its corresponding preset encoded spectral range.

[0033] According to an embodiment of the present disclosure, the method further includes:

[0034] Based on the spectral range continuity of the at least two split light beams, data fusion of overlapping regions is performed on the at least two pieces of spectral information to generate continuous spectral information carrying the response information of the sample to be measured and covering the target spectral range.

[0035] According to an embodiment of the present disclosure, the method further includes:

[0036] When irradiating the combined light beam onto the sample to be measured, the pump light beam is irradiated onto the sample to be measured with a fixed pulse, so that the incident light beam is attached with the response information of the sample to be measured in the excited state;

[0037] Performing radial spatial decoupling beam splitting on the incident light beam to obtain at least two split light beams;

[0038] Respectively measuring the spectral information of each of the split light beams.

[0039] According to an embodiment of the present disclosure, the respectively measuring the spectral information of each of the split light beams includes:

[0040] Collecting first spectral information at the moment when the pump light beam first excites the sample to be measured;

[0041] In the subsequent N - 1 pump pulse periods, spectral information is collected with a preset time interval increased in sequence, where the total delay of the Nth collection is equal to the duration of a single pump pulse period, and N is a positive integer greater than 2.

[0042] According to an embodiment of the present disclosure, the method further includes:

[0043] Receiving a test light beam generated by a test light source, performing radial spatial decoupling beam splitting processing on the test light beam to obtain at least two split light beams, and respectively measuring the spectral information of each of the split light beams.

[0044] A second aspect of the present disclosure provides a spectral measurement device, including:

[0045] A light beam input component configured to radially spatially superpose at least two sub - light beams along the optical axis to form a combined light beam, where the total spectral range of the at least two sub - light beams continuously covers the target spectral range;

[0046] A sample reaction component provided with a first optical window and a second optical window opposed along the optical axis, the combined light beam is incident on the action area of the sample to be measured through the first optical window, and the second window is used for outputting the incident light beam formed after acting on the sample to be measured;

[0047] A light beam detection component, the light beam detection component includes:

[0048] A beam splitting element that splits an incident light beam into at least two split light beams according to a radial distribution, wherein the spectral ranges of the at least two split light beams respectively correspond to and are consistent with the spectral ranges of the at least two sub-light beams.

[0049] At least two detection units, each of which is respectively disposed in the optical path of the corresponding split light beam and is used to obtain spectral information within the spectral measurement range of each split light beam. Description of the Drawings

[0050] Through the following description of the embodiments of the present disclosure with reference to the drawings, the above content and other objects, features, and advantages of the present disclosure will become clearer. In the drawings:

[0051] Figure 1 Schematically shows a flowchart of a spectral measurement method according to an embodiment of the present disclosure;

[0052] Figure 2 Schematically shows a flowchart of operation S100 of the spectral measurement method according to an embodiment of the present disclosure;

[0053] Figure 3 Schematically shows a flowchart of operation S400 of the spectral measurement method according to an embodiment of the present disclosure;

[0054] Figure 4 Schematically shows a flowchart of the spectral measurement method according to an embodiment of the present disclosure in the second measurement mode;

[0055] Figure 5 Schematically shows a flowchart of operation S300A of the spectral measurement method according to an embodiment of the present disclosure;

[0056] Figure 6 Schematically shows a structural diagram of a first embodiment of a spectral measurement device according to an embodiment of the present disclosure;

[0057] Figure 7 Schematically shows a structural diagram of a second embodiment of a spectral measurement device according to an embodiment of the present disclosure;

[0058] Figure 8 Schematically shows a first structural block diagram of a second embodiment of a spectral measurement device according to an embodiment of the present disclosure;

[0059] Figure 9 Schematically shows a second structural block diagram of a second embodiment of a spectral measurement device according to an embodiment of the present disclosure;

[0060] Figure 10 Schematically shows a structural diagram of a beam combining element of a spectral measurement device according to an embodiment of the present disclosure;

[0061] Figure 11The structural diagram of the beam splitting part of the spectral measurement device according to the embodiments of the present disclosure is schematically shown. Detailed implementation manners

[0062] In order to enable those skilled in the art of the present technology to better understand the technical solutions in the present disclosure, the following will clearly and completely describe the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present disclosure.

[0063] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0064] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used here should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0065] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning commonly understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc. In the case of using expressions such as "at least one of A, B, or C, etc.", generally, it should be interpreted according to the meaning commonly understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.

[0066] In traditional spectral measurement technologies, light sources in different bands need to independently irradiate the sample to be measured and sequentially switch the spectral splitting elements for step-by-step measurement. Its defects are as follows: First, due to the sequential excitation of light sources in each band, it is difficult to ensure that the sample is synchronously detected in the same physical state, resulting in poor coordination of spectral data across bands; Second, the spectral splitting element is limited by the discrete switching mechanism and cannot achieve continuous coverage and efficient decoupling of the light beam in the ultra-wideband range. Especially in wide spectral band scenarios such as infrared to terahertz, multi-stage spectral splitting operations will introduce significant energy loss and time delay, making it difficult to meet the requirements of rapid measurement.

[0067] Figure 1 Schematically shows a flowchart of a spectral measurement method according to an embodiment of the present disclosure.

[0068] As an aspect of an embodiment of the present disclosure, as Figure 1 shown, the spectral measurement method includes operations S100 - S400.

[0069] In operation S100, at least two sub - beams are spatially superposed radially along the beam propagation direction to form a combined beam, wherein the total spectral range of the at least two sub - beams continuously covers the target spectral interval.

[0070] In operation S200, the combined beam is irradiated onto the sample to be measured to obtain an incident beam with the response information of the sample to be measured attached.

[0071] In operation S300, radial spatial decoupling beam splitting is performed based on the incident beam to obtain at least two split beams, wherein the spectral ranges of the at least two split beams respectively correspond to and are consistent with the spectral ranges of the at least two sub - beams.

[0072] In operation S400, the spectral information of each split beam is measured respectively.

[0073] Specifically, in some embodiments, two sub-beams covering different spectral ranges (for example, the first sub-beam covers the near-infrared to far-infrared band, and the second sub-beam covers the terahertz band) are spatially superposed in the radial space along the beam propagation direction. For example, the two sub-beams adjust their spatial distribution patterns through beam transformation, so that the first sub-beam occupies the radial central region of the combined beam, and the second sub-beam is distributed in the radial outer region of the combined beam. The two beams maintain a nested and radially separated state in space, and the spectral ranges of the two beams do not overlap or partially overlap, thereby forming a combined beam with a spatial-spectral mapping. For another example, the two sub-beams can adjust their spatial distribution patterns through beam transformation, so that the first sub-beam occupies the first radial region on one side of the combined beam, and the second sub-beam is distributed in the second radial region on the opposite side of the combined beam. The two beams maintain a parallel and radially separated state in space. In some embodiments, the combined beam is irradiated onto the sample to be measured in a common-path form, and the response information of absorption, reflection, or transmission generated by the sample for beams with different spectral ranges is synchronously loaded into the combined beam; after the combined beam acts on the sample, an incident beam is formed, and the incident beam carrying the sample response information is radially spatially decoupled and split. Radial spatial decoupling and splitting means using spatial separation means to split the incident beam into two sub-beams along the original radial distribution characteristics. For example, in an embodiment where the two sub-beams maintain a nested combined state in the space of the combined beam, the spectral range of the first split sub-beam can correspond to the spectral range of the beam in the central region of the combined beam, and the spectral range of the first split sub-beam corresponds to the spectral range of the first sub-beam. The spectral range of the second split sub-beam can correspond to the spectral range of the outer region of the combined beam, and the spectral range of the second split sub-beam corresponds to the spectral range of the second sub-beam; finally, the two split sub-beams are respectively introduced into independent spectral detection channels, and spectral detection channels capable of measuring the spectral range of the first sub-beam and spectral detection channels capable of measuring the spectral range of the second sub-beam are used for measurement respectively. In the embodiments of the present disclosure, spectral information in their respective spectral ranges is obtained through parallel acquisition and processing, and the data of the two channels can be integrated based on the continuity of spectral coverage to generate a complete spectrum covering the ultra-wideband target interval.

[0074] In the spectral measurement method provided by the embodiments of the present disclosure, through the collaborative design of radial spatial superposition and radial spatial decoupling and splitting, not only the systematic error introduced by the timing error of multiple light sources is avoided, but also the limitation of traditional spectral splitting methods on the continuous coverage of wide spectral bands is eliminated, significantly improving the efficiency and data consistency of ultra-wideband spectral measurement.

[0075] According to some exemplary preferred embodiments of the present disclosure, at least two sub-beams are spatially superposed along the radial space of the beam, specifically including: spatially superposing at least two sub-beams in a coaxial nested structure, so that in the combined beam, at least two sub-beams are distributed sequentially from the center of the beam outward in the radial direction along the beam propagation direction.

[0076] According to the spectral measurement method of the embodiments of the present disclosure, the uniformity problem of the irradiation response information of the sample to be measured can be improved, so that sub-beams in different spectral ranges can uniformly irradiate the core area of the object to be measured in the combined beam, avoiding the problem that some core areas are not irradiated by the sub-beams in a certain spectral range. By introducing a coaxial nested spatial superposition structure, first, multiple sub-beams with different spectral ranges, for example, the first sub-beam covers the near-infrared to mid-infrared band, and the second sub-beam covers the far-infrared to terahertz band, are subjected to coaxial spatial registration. Among them, the first sub-beam is adjusted by the beam transformation component to form a central beam current, and the second sub-beam is adjusted by the beam transformation component to form an annular beam current. The two are superimposed in a strictly coaxial manner, so that the central beam current is completely embedded inside the annular beam current, forming a combined beam with seamless central-peripheral connection. When the combined beam is focused and irradiated on the sample to be measured, the central beam current preferentially covers the core area of the sample to be measured and excites a local response, and the peripheral annular beam current forms a uniformly distributed irradiation ring around the central beam current, which can also achieve irradiation response to parts in all directions of the core area, eliminating the problem of uneven and incomplete response information caused by different beams with different spectral ranges irradiating different areas of the sample to be measured.

[0077] In some embodiments, the incident beam formed after interacting with the sample is coaxially reversely decoupled, and the central beam current and the annular beam current are separated into multiple independent sub-beams along the original radial distribution path. Each sub-beam carries the response information of the sample to be measured in different spectral ranges. During this process, the beam arrangement characteristics of the coaxial nested structure ensure that the two sub-beams are completely synchronously excited in the time and space dimensions, so that the response information of the sample to be measured can be loaded into the corresponding sub-beams without phase difference. Finally, through the fusion and reconstruction of the spectral data of the sub-beams, an ultra-wideband measurement result with significantly improved spatial resolution and spectral integrity is obtained. At the same time, this method combines coaxial nested superposition and spatial complementary excitation mechanisms, breaking through the spatial uniformity bottleneck of traditional discrete beam superposition schemes, providing a technical basis for high-precision spectral analysis of the entire region of complex-shaped samples.

[0078] Figure 2 Schematically shows a flowchart of operation S100 of the spectral measurement method according to the embodiments of the present disclosure.

[0079] As Figure 2 shown, in some exemplary embodiments of the present disclosure, the spatial superposition of at least two sub-beams in the spectral measurement method according to the coaxial nested structure includes: operation S110 to operation S120.

[0080] In operation S110, one of the sub-beams is subjected to beam shrinking and collimation processing to form a reference sub-beam located at the center of the combined beam;

[0081] In operation S120, beam expansion and collimation processing is performed on the remaining sub-beams to form peripheral sub-beams, and the peripheral sub-beams are arranged in sequence around the outer periphery of the reference sub-beam.

[0082] According to the spectral measurement method of the present disclosure, the problem of easily introducing energy loss or wavefront distortion due to complex adjustment of the original cross-sectional size of the sub-beams often required to achieve spatial matching and merging of the beams is avoided. In some embodiments, through the collaborative control of directional beam contraction and collimation and beam expansion and collimation, efficient spatial superposition is achieved while maintaining the original energy density of the sub-beams.

[0083] Specifically in operation S110, beam contraction and collimation processing is applied to the first sub-beam, causing the first sub-beam to converge into a thin beam with a diameter smaller than the original size, while maintaining collimation to form a reference sub-beam with a high energy density.

[0084] Specifically in operation S120, beam expansion and collimation processing is performed on the second sub-beam to expand its beam cross-section to a preset annular size, causing the second sub-beam to form a peripheral sub-beam with an inner diameter matching the boundary of the reference sub-beam; finally, the contracted reference sub-beam and the expanded peripheral sub-beam are superimposed in a strictly coaxial manner, causing the reference sub-beam to be completely embedded in the annular region of the peripheral sub-beam, with the cross-sections of the two beams nested seamlessly and the propagation directions being the same. This method, through the symmetric beam transformation of beam contraction / beam expansion, not only retains the original spectral characteristics and energy distribution of each sub-beam, but also avoids the problem of beam overlap easily generated in conventional beam merging methods, providing a standardized operation paradigm for the rapid construction of a coaxial nested structure.

[0085] According to some exemplary embodiments of the present disclosure, a radial reverse separation process is performed on an incident beam having a coaxial nested structure, such that the spectral ranges of the separated sub-beams are the same as the spectral ranges of the sub-beams at the corresponding nested positions in the combined beam.

[0086] According to the spectral measurement method of the present disclosure, by analyzing the spatial characteristics of the coaxial nested incident beam carrying the sample response information, the central beam current corresponding to the reference sub-beam in its radial distribution and the boundary positions of the annular beam currents corresponding to the peripheral sub-beams are identified. Specifically, in some embodiments, based on the recognition results, the optical parameters of the beam splitting component are configured, and a beam splitting method of central transmission - peripheral reflection can be adopted. Among them, the set diameter of the central transmission area strictly matches the cross-sectional size of the reference sub-beam in the incident beam. At the same time, the set inner diameter of the peripheral reflection area coincides with the outer diameter of the corresponding reference sub-beam, and the set outer diameter of the peripheral reflection area is consistent with the outer diameter of the corresponding peripheral sub-beam. When the incident beam undergoes beam splitting processing, the beam of the corresponding reference sub-beam is completely transmitted and separated into a split beam, and its spectral range is exactly the same as that of the reference sub-beam before merging. While the beam of the corresponding peripheral sub-beam is stripped into another split beam, and its spectral range strictly corresponds to that of the peripheral sub-beam before merging. In the method provided in this embodiment, the spatial parameters of the beam splitting processing adopted can form an inverse mapping relationship with the nested structure of the original merged beam, ensuring that the split beams after decoupling have no excessive overlap in the spectral dimension and no crosstalk in the spatial dimension, providing a high-fidelity input for subsequent independent spectral detection.

[0087] According to some exemplary preferred embodiments of the present disclosure, the reference sub-beam is an infrared beam in the near-infrared to far-infrared band, and the peripheral sub-beam is a terahertz beam. The spectral measurement method further includes: expanding and collimating the split beam corresponding to the reference sub-beam to form a reference split beam; performing transmission and reflection beam splitting processing on the reference split beam to form a first split beam for measuring the near-infrared to mid-infrared band and a second split beam for measuring the far-infrared band.

[0088] Collimate the split beam corresponding to the peripheral sub-beam to form a peripheral split beam for measuring the terahertz band.

[0089] In the ultra-wide spectrum beam splitting scenario, traditional solutions have difficulty balancing the detection sensitivity and spectral resolution of sub-beams due to the spectral range limitations and energy loss of the splitting elements. In the embodiments of the present disclosure, high-fidelity beam splitting is achieved through a hierarchical decoupling strategy. For example, the sub-beam corresponding to the reference sub-beam covering the near-infrared to far-infrared band is subjected to secondary beam splitting to avoid more than two sub-beams in a single beam splitting. In a specific implementation, for the sub-beam corresponding to the reference sub-beam obtained by coaxial nested reverse beam splitting (covering the near-infrared to far-infrared band), its spatial distribution morphology can be adjusted through collimation processing to eliminate the wavefront distortion introduced by the transmission path, forming a reference sub-beam with uniform energy density; further hierarchical decoupling processing is implemented, and in some embodiments, wavelength selection can be used for Beam splitting, such as wavelength-selective transmission and reflection mode, the transmission channel is optimized for the near-infrared to mid-infrared band, and the reflection channel is optimized for the far-infrared band, so that the components of different spectral ranges in the split beam are separated according to preset characteristics, the transmission channel outputs an independent spectrum from the near-infrared to mid-infrared band, and the reflection channel outputs a complete signal beam in the far-infrared band, thereby achieving spectrum isolation with zero crosstalk; in other embodiments, a non-wavelength-selective light intensity splitting method can also be used to split the reference split beam into two paths according to a fixed energy ratio, and each path is subsequently used to achieve spectrum screening corresponding to its preset spectral range segment, providing highly flexible bandwidth customization capabilities.

[0090] In some embodiments, for the split beams (covering the terahertz band) corresponding to the peripheral sub-beams obtained by coaxial nested reverse beam splitting, their transmission characteristics can be adjusted through collimation processing, beam divergence and mode distortion can be suppressed, and collimated split beams covering the terahertz spectrum range with regular cross-sectional morphology and stable energy distribution can be formed, and spectral information measurement can be performed on the collimated split beams in the terahertz spectrum range of the terahertz beam.

[0091] In the hierarchical decoupling method provided in the embodiments of the present disclosure, through the spectrum / energy diversion of the sub-beam (covering the near-infrared to far-infrared bands) corresponding to the reference sub-beam, and the transmission optimization synergy with the sub-beam (covering the terahertz band) corresponding to the peripheral sub-beam, the detection bandwidth of each sub-channel is targetedly reduced while maintaining the ultra-wideband detection capability, thereby significantly improving the weak signal analysis capability and anti-environmental interference performance, and providing technical support for the extraction of complex spectral features.

[0092] In some exemplary embodiments of the present disclosure, the spectral measurement method further includes: focusing the combined light beam so that the combined light beam after focusing forms a spatial focus at the sample to be measured.

[0093] According to another specific embodiment of the present disclosure, the spectrum measurement method further includes: performing beam expansion and collimation processing on the incident light beam, so that the incident light beam after beam expansion and collimation can be radially spatially decoupled and split into at least two sub-beams.

[0094] According to the spectral measurement methods of the above two disclosed embodiments, in the collaborative optimization of wide-spectrum beam excitation and beam splitting, the problem that it is difficult to balance the excitation efficiency and beam splitting accuracy due to neglecting the beam shape is solved. In this embodiment, through the cascaded processing of focused excitation and beam expansion and collimation, the above two problems can be solved simultaneously.

[0095] Specifically, in one embodiment, the combined beam formed by coaxial nested superposition is focused, and by adjusting the curvature parameter of the combined beam, the spatial focus where the beam converges is accurately positioned at the action area of the sample to be measured. The focused combined beam forms a high-intensity micro-region excitation point on the sample surface, and its energy density is significantly increased compared with the collimated beam, which can effectively excite the weak absorption characteristics and deep structure response of the sample, and at the same time suppress the interference of stray signals in the edge region.

[0096] Specifically, in another embodiment, during the focusing process, although the focusing effect enhances the excitation efficiency, it causes significant divergence of the beam after penetrating the sample due to scattering and diffraction effects, forming an incident beam with a blurred spatial distribution. Even without the focusing process, the beam will also experience significant divergence after penetrating the sample due to scattering and diffraction effects. To eliminate the influence of divergence on the beam splitting accuracy, the incident beam is collimated and expanded, so that the divergent beam is restored to a size and collimation equivalent to the original combined beam, and a clear radial spatial distribution characteristic is reconstructed. Among them, the nested spatial structure of the incident beam after the collimation and expansion process forms an inverse mapping relationship with the original combined beam, providing a well-defined input condition for subsequent radial decoupling beam splitting. This method ensures both high-efficiency energy coupling during the sample interaction stage and the spatial-spectral mapping accuracy during the beam splitting stage through cascaded control of focused excitation and beam expansion and collimation.

[0097] Figure 3 A flowchart of operation S400 of the spectral measurement method according to an embodiment of the present disclosure is schematically shown.

[0098] As Figure 3 shown, in some exemplary embodiments of the present disclosure, the method for obtaining the spectral information of each split beam specifically includes: operation S410 to operation S420.

[0099] In operation S410, spectral encoding processing is performed on each split beam to generate an encoded beam having a spectrum range matching the corresponding sub-beam and carrying spatial phase characteristics.

[0100] In operation S420, identification processing is performed on each encoded beam to obtain the spectral information of each split beam.

[0101] Specifically, in operation S410, for each independent sub-beam obtained by radial decoupling beam splitting, such as the reference sub-beam and the peripheral sub-beam, spectral encoding processing is performed on the phase modulation characteristics corresponding to specific spectral ranges respectively. In the spectral encoding processing, the sub-beams generate spatial phase modulation associated with spectral components, forming encoded beams carrying unique encoding features.

[0102] Specifically, in operation S420, each encoded beam is collected and detected in parallel to obtain its spectral information. The collected data can be reversely analyzed through a preset phase decoding algorithm to strip off environmental noise interference and reconstruct the original spectral information of each sub-beam.

[0103] According to some exemplary embodiments of the present disclosure, the spectral measurement method further includes: performing spectral range screening processing on each sub-beam so that the spectral range of each sub-beam entering spectral encoding is consistent with its corresponding preset encoded spectral range.

[0104] In the pre-processing of spectral encoding, direct encoding of unoptimized sub-beams is likely to cause encoding feature distortion due to blurred spectral boundaries or residual clutter. This embodiment realizes optimization through a spectral range screening mechanism. In some embodiments, for sub-beams with clear spectral boundaries obtained by spatial radial decoupling beam splitting, the spectral range screening processing is used to suppress the stray components at the spectral edges, so that the spectral range of the sub-beams entering spectral encoding is strictly limited to the preset spectral range corresponding to the sub-beams and detection channels, significantly suppressing the interference of spectral range crosstalk on spatial phase encoding.

[0105] In another embodiment, for sub-beams obtained by energy ratio beam splitting, the spectral range screening processing is used to dynamically intercept the spectral ranges of each sub-beam, and sub-beams with spectral ranges that exactly match the preset spectral range of the corresponding detection channel are screened out, eliminating the problems of spectral range offset or bandwidth overflow that may be introduced during the beam splitting process.

[0106] In some embodiments, the screening mechanism of the spectral range screening processing is adaptively enabled according to the difference in beam splitting modes, which not only ensures the encoding purity of high-fidelity sub-beams but also enhances the system compatibility in the composite beam splitting scenario.

[0107] According to some exemplary embodiments of the present disclosure, the spectral measurement method further includes: fusing the data in the overlapping regions of at least two spectral information according to the spectral range continuity of at least two sub-beams to generate continuous spectral information carrying the response information of the sample to be measured and covering the target spectral interval.

[0108] In some embodiments, for the spectral information of multiple split light beams obtained through spatial decoupling beam splitting, the spectral ranges thereof respectively correspond to the near-infrared to mid-infrared, far-infrared, and terahertz bands. First, based on a preset spectral mapping relationship, the overlapping regions between the split light beams are located, and the response signals of all split light beams within these regions are extracted for cross-correlation analysis to correct the spectral information. Then, the spectral information of the corrected split light beams is spliced and extended according to the principle of spectral continuity to generate a continuous spectral curve covering the target interval.

[0109] In some exemplary embodiments of the present disclosure, the spectral measurement method includes three measurement modes. In the first measurement mode of the spectral measurement method, the method is to irradiate the combined light beam onto the sample to be measured for spectral measurement and analysis of the sample to be measured. In the second measurement mode of the spectral measurement method, the method is to irradiate the pump beam and the combined light beam onto the sample to be measured together for spectral measurement and analysis of the sample to be measured. In the third measurement mode of the spectral measurement method, the method is to only receive the test light beam generated by the test light source and perform spectral measurement and analysis on the test light beam.

[0110] As Figure 4 shown, in the second measurement mode, the spectral measurement method further includes: operations S100A to S300A.

[0111] In operation S100A, when irradiating the combined light beam onto the sample to be measured, the pump beam is irradiated onto the sample to be measured with a fixed pulse so that the incident light beam carries the response information of the sample to be measured in the excited state.

[0112] In operation S200A, radial spatial decoupling beam splitting is performed based on the incident light beam to obtain at least two split light beams.

[0113] In operation S300A, the spectral information of each split light beam is measured respectively.

[0114] In some embodiments, dynamic information analysis is achieved through the temporal and spatial coordination of pulse excitation and broadband detection. In a specific embodiment, in operation S100A, while continuously irradiating the combined light beam formed by coaxial nesting and superposition onto the sample to be measured to obtain its steady-state response information, the pump beam is modulated into a pulse sequence with a fixed frequency and a fixed pulse width through an independent optical path. After the pump beam and the combined light beam are precisely synchronized in the space-time dimension, they act on the sample surface together. The pulse energy of the pump beam excites the sample into a transient excitation state, and the physical or chemical properties of the sample to be measured change dynamically during the pulse action. When the combined light beam penetrates the sample, it synchronously loads the dynamic response information of the sample to be measured in the excited state, forming an incident light beam carrying transient excitation characteristics. In operations S200A and S300A, the radial spatial decoupling beam splitting method is adopted to split the incident light beam into split light beams with spectral ranges strictly corresponding to the sub-beams, and the ultra-wideband spectral information of the sample to be measured is respectively collected.

[0115] As Figure 5 shown, in some exemplary embodiments of the present disclosure, specifically measuring the spectral information of each sub-beam includes: operations S310A to S320A.

[0116] In operation S310A, the first spectral information is collected at the moment when the pump beam first excites the sample to be measured;

[0117] In operation S320A, in the subsequent N - 1 pump pulse periods, the spectral information is collected by delaying in sequence with a preset time interval increased each time, where the total delay of the Nth collection is equal to the duration of a single pump pulse period, and N is a positive integer greater than 2.

[0118] In some embodiments, when the pump beam irradiates the sample to be measured with a fixed pulse period, at the trigger moment of the rising edge of the first pulse in operation S310A, the spectral acquisition is synchronously started to obtain the first spectral information in the initial excitation state; in operation S320A, in subsequent pulse periods, by successively accumulating and delaying the trigger signal, the spectral acquisition times of the 2nd to the Nth times are fixed to be delayed by a preset time interval (such as in the order of 1 ps to 1 ns) compared with the previous time. During this process, the total delay of the Nth collection is strictly equal to the duration of a single pulse period, ensuring the integrity of the timing coverage. After the spectral data of each sub-beam collected each time are arranged in the order of delay, an ultra-wideband transient response curve of the sample under the excitation action can be constructed to accurately depict the dynamic trajectory of the evolution of its physical or chemical properties over time. This spectral measurement method provides high-precision time-resolved measurement capabilities for the study of ultrafast processes such as excited-state relaxation and energy transfer path analysis through the collaborative control of timing extension and fixed-period constraint.

[0119] In a specific embodiment of the present disclosure, in the third measurement mode, the spectral measurement method includes: operation S100B.

[0120] In operation S100B, in the state of stopping receiving the combined beam and the pump beam, or blocking the incident beam, the test beam generated by the test light source is received, and the test beam is subjected to radial spatial decoupling beam splitting processing to obtain at least two sub-beams, and the spectral information of each sub-beam is respectively measured.

[0121] In some embodiments, the test beam is directly radially spatially decoupled and split. Based on a preset spatial separation logic, such as the beam splitting scheme of transmitting in the central region and reflecting in the peripheral region in the above embodiments, the test beam is split into several sub-beams. Since the spectral range of the test light source is unknown, each sub-beam needs to be further processed for spectral range screening. In a specific embodiment, for the sub-beam formed by transmission in the central region, sub-beams in the spectral range from near-infrared to far-infrared can be screened out, and for the peripheral sub-beams, sub-beams in the terahertz spectral range can be extracted. Each filtered sub-beam is synchronously collected based on the detection channel corresponding to the spectral range, and finally, a full-spectrum continuous spectrum of the test beam is generated by splicing the spectral ranges of each filtered sub-beam.

[0122] Based on the above spectral measurement method, an embodiment of the present disclosure also provides a spectral measurement device. The following will be combined with Figures 6 to 9 to describe this device in detail.

[0123] Figure 6 Schematically shows the structural diagram of the first embodiment of the spectral measurement device according to an embodiment of the present disclosure; Figure 7 Schematically shows the structural diagram of the second embodiment of the spectral measurement device according to an embodiment of the present disclosure; Figure 8 Schematically shows the first structural block diagram of the second embodiment of the spectral measurement device according to an embodiment of the present disclosure; Figure 9 Schematically shows the second structural block diagram of the second embodiment of the spectral measurement device according to an embodiment of the present disclosure.

[0124] As Figures 6 to 9 shown, the spectral measurement device includes a beam input component 4A, a sample reaction component 5A, and a beam detection component 100A.

[0125] The beam input component 4A is configured to superpose at least two sub-beams radially along the optical axis to form a combined beam, wherein the sum of the spectral ranges of the at least two sub-beams continuously covers the target spectral interval.

[0126] The sample reaction component 5A is provided with a first window 51A and a second window 52A opposed to each other along the optical axis. The combined beam is incident on the area of the sample to be measured through the first window 51A, and the second window 52A is used for the output of the incident beam formed after acting on the sample to be measured.

[0127] The beam detection component 100A includes:

[0128] A beam splitting element 1A, which separates the incident beam into at least two sub-beams according to a radial distribution, wherein the spectral ranges of the at least two sub-beams respectively correspond to and are consistent with the spectral ranges of the at least two sub-beams.

[0129] At least two detection units 2A, each detection unit 2A is respectively arranged in the optical path of the corresponding split beam, and is used to obtain the spectral information within the spectral measurement range of each split beam.

[0130] In some embodiments, the beam input component 4A is configured to spatially superpose at least two sub-beams along the radial direction of the optical axis to form a combined beam, where each sub-beam covers a different spectral range within the target ultra-wideband spectral range. In one embodiment, one sub-beam covers the low-frequency spectral range, and the other sub-beam covers the high-frequency spectral range, and the spectral ranges of the sub-beams do not overlap or partially overlap. After the spectral ranges of all sub-beams are superposed, they form a continuous spectral coverage of the target spectral range.

[0131] In some embodiments, the combined beam is incident on the sample interaction area to be measured through the first window 51A of the sample reaction component 5A. After interacting with the sample, the outgoing beam carrying the sample response characteristics is output as the incident beam through the second window 52A. The beam splitting element 1A of the beam detection component 100A includes at least one radial beam splitting member 13. According to the radial spectral range distribution characteristics of the incident beam, the beam splitting element 1A radially separates the incident beam into split beams corresponding to the number of sub-beams through at least one radial beam splitting member 13. That is, if two sub-beams are used to form a combined beam, through the radial beam splitting member 13, the combined beam can be split into two split beams, where the radial distribution area corresponding to each split beam in the incident beam is the same as the radial distribution area corresponding to each sub-beam in the combined beam before combination. Each detection unit 2A is arranged in the optical path of the corresponding split beam, and the spectral measurement range of each detection unit 2A is strictly the same as the original spectral range of the sub-beam corresponding to the split beam before combination. Based on this structure, the broadband spectral information of the combined beam is decoupled and split into independent measurement tasks of sub-spectral ranges corresponding one-to-one with the original sub-beams, which not only retains the energy and measurement range advantages of the superposition of multiple sub-beams, but also avoids data analysis errors caused by spectral mixing through the detection logic of spectral range matching. Finally, the complete ultra-wideband spectral information is generated through the fusion of the data of each detection unit 2A.

[0132] As Figures 6 to 9 shown, in some exemplary embodiments, the spectral measurement device further includes: a test light input component 7, configured to receive a test beam from the outside; a reflection component 8, the reflection component 8 is movably arranged outside the second window 52A along a first direction, where the first direction is set at an angle with the optical path direction of the incident beam; wherein, when the reflection component 8 is located on the optical path of the incident beam, the test beam received by the test light input component 7 can irradiate the reflection component 8 and be reflected by the reflection component 8 to the beam splitting element 1A for splitting and measuring the test beam.

[0133] As Figures 6 to 10As shown, according to some exemplary embodiments of the present disclosure, the beam input assembly 4A includes: at least two light sources; and at least one beam combining element 41. The beam combining element 41 has a first reflecting portion 411 and a first transmitting portion 412. The first transmitting portion 412 exposes the central cross-section of a light source to form a transmitted sub-beam, and the first reflecting portion 411 covers the peripheral cross-section of the light source to form a reflected sub-beam. The first reflecting portion 411 and the first transmitting portion 412 are configured to radially nest the reflected sub-beam and the transmitted sub-beam along the optical axis to form a combined beam.

[0134] Specifically, in some embodiments, as Figure 10 shown, the beam combining element 41 adopts a spatial modulation structure with a central transmission region and a peripheral reflection region. The first reflecting portion 411 corresponds to the peripheral reflection region, and the first transmitting portion 412 corresponds to the central transmission region. In other embodiments, the first reflecting portion 411 and the first transmitting portion 412 can also be provided as two optical elements, and a combined beam that is radially nested is combined through optical path matching. In some embodiments, the beam generated by the first light source is directly transmitted through the central transmission region to form a reference sub-beam; the beam generated by the second light source is incident on the peripheral reflection region and forms a peripheral sub-beam surrounding the reference sub-beam after reflection. The reference sub-beam and the peripheral sub-beam are radially nested and combined along the optical axis into a coaxial propagating combined beam, and the cross-section of the combined beam presents a superimposed distribution of different spectral ranges.

[0135] As Figures 6 to 9 、 Figure 11 shown, according to some exemplary embodiments of the present disclosure, the beam splitting element 1A includes a radial beam splitting member 13: The radial beam splitting member 13 includes a second reflecting portion 131 and a second transmitting portion 132. The second transmitting portion 132 exposes the central cross-section of the incident beam to form a transmitted split beam, and the second reflecting portion 131 covers the remaining peripheral cross-section of the incident beam to form a reflected split beam.

[0136] Specifically, in some embodiments, as Figure 11 shown, the radial beam splitting member 13 of the beam splitting element 1A has a central transmission region and a peripheral reflection region. Among them, the second reflecting portion 131 corresponds to the peripheral reflection region, and the second transmitting portion 132 corresponds to the central transmission region. In other embodiments, the second reflecting portion 131 and the second transmitting portion 132 can also be provided as two optical elements, and the combined beam that is radially nested is reversely decomposed through optical path matching. In some embodiments, the design of the beam splitting element 1A and the beam combining element 41 are inverse operations of each other. Specifically, as Figure 11As shown, the second transmission part 132 of the radial beam splitter 13 exposes the central cross-section of the incident beam, where the central cross-section of the incident beam corresponds to the radial distribution area of the reference sub-beam in the combined beam, allowing this part of the beam to directly transmit to form the first sub-beam, and the spectral range of the first sub-beam is consistent with the spectral range of the original reference sub-beam; at the same time, the second reflection part 131 of the radial beam splitter 13 covers the remaining peripheral cross-section of the incident beam, where the remaining peripheral cross-section corresponds to the radial distribution area of the peripheral sub-beam in the combined beam, reflecting this part of the beam to form the second sub-beam, and the spectral range of the second sub-beam is consistent with the spectral range of the original peripheral sub-beam. In some embodiments, the first sub-beam enters the detection part 2A corresponding to the spectral range, and the second sub-beam enters the detection part 2A corresponding to the spectral range. The spectral ranges of the two sub-beams are strictly corresponding to the spectral range characteristics of the original sub-beams. Through this structure, the spectral-radial spatial mapping relationship of the combined beam is accurately decoupled, and each sub-beam independently enters the corresponding matching detection part 2A for spectral measurement, and finally the complete spectrum covering the ultra-wideband range is reconstructed through data fusion.

[0137] As Figures 6 to 9 shown, in some exemplary embodiments, the beam splitting element 1A further includes at least one beam splitting part 11, the beam splitting part 11 covers the cross-section of the sub-beam, and the beam splitting part 11 is configured to split the sub-beam into a first sub-beam reflected by the beam splitting part 11 and a second sub-beam transmitted by the beam splitting part 11 for further beam splitting.

[0138] In some specific embodiments, the beam splitting part 11 is a planar beam splitter or a beam splitting sheet, and its reflection surface and transmission surface cover the entire cross-section of the sub-beam. The sub-beam is split into two sub-beams by the beam splitting part 11 according to a preset energy ratio, for example, 50% reflection and 50% transmission: the first sub-beam changes the propagation direction after reflection, and the second sub-beam transmits and maintains the original direction. The spectral ranges of the two sub-beams are the same as that of the incident light, but the energy is split proportionally.

[0139] In some other specific embodiments, the beam splitting part 11 is a wavelength-selective beam splitting component. In one embodiment, the beam splitting part 11 can be a dichroic beam splitter. In another embodiment, the beam splitting part 11 can be a metasurface beam splitter. The reflection and transmission characteristics of the beam splitting part 11 change with the wavelength. That is, in one embodiment, the beam splitting part 11 has a high reflectivity for terahertz-band light and a high transmittance for infrared-band light. The beam splitting part 11 will reflect the beam to form a sub-beam corresponding to the terahertz band and transmit to form another sub-beam corresponding to the infrared band. The spectral ranges of the two sub-beams do not overlap and the boundaries are clear. The beam splitting part 11 directly realizes frequency-domain screening through physical characteristics, reducing the subsequent filtering requirements.

[0140] As Figures 6 to 9As shown, in some exemplary embodiments, the detection unit 2A includes: an encoding element 21 disposed on the optical path of the split beam, and the encoding element 21 is configured to perform spectral encoding on the split beam so that the split beam is formed into an encoded beam having a spatial phase distribution; a detection element 22 disposed on the optical path of the encoded beam, and the detection element 22 is configured to receive the encoded beam and generate spectral information of the encoded beam.

[0141] In some embodiments, an encoding element 21 is disposed on the optical path of each split beam. The encoding element 21 encodes the split beam into an encoded beam having specific distribution characteristics by applying spatial phase modulation to the split beam. In a specific embodiment, the encoding element 21 may be an arrayed metasurface including electromagnetic microstructures or an arrayed metamaterial including electromagnetic microstructures, and is configured to perform transmissive high-random spectral encoding or reflective high-random spectral encoding on the split beam; in the embodiment where the encoding element 21 is an arrayed metasurface, randomly distributed nanostructures are introduced into the cross-section of the split beam, so that light of different wavelengths generates different phase delays, thereby forming a spatial interference pattern related to the spectrum during propagation, and the encoded beam after encoding is received by the detection element 22; in a specific embodiment, the detection element 22 may be an arrayed optoelectronic sensor, such as a CCD, CMOS or MCT detector array. The detection element 22 can convert the spatial intensity distribution of the encoded beam into an electrical signal and inversely calculate the original spectral information through a machine learning algorithm; in some embodiments, through the combined action of the wavelength selection of the beam splitting element 1A and the spatial modulation of the encoding element 21, the problems of light energy loss or spectral range limitation introduced by the filtering element in the traditional spectrometer are solved, and high-precision spectral measurement in the frequency division domain can be realized without additional filtering. Combining with the parallel acquisition ability of the array detector, the spectral reconstruction speed and resolution are significantly improved.

[0142] As Figures 6 to 9 shown, in some exemplary embodiments, the detection unit 2A further includes: a filtering element 23 disposed between the beam splitting element 1A and the encoding element 21, and the filtering element 23 is located on the optical path of the split beam. The filtering element 23 is configured to filter out the split beam corresponding to the spectral measurement range of the detection unit 2A from the split beam.

[0143] As Figures 6 to 9 shown, in some exemplary embodiments, the detection unit 2A further includes: an achromatic lens element 92 disposed between the encoding element 21 and the detection element 22, and the achromatic lens element 92 is located on the optical path of the encoded beam.

[0144] Specifically, in some embodiments, the encoded light beam modulated by the encoding element 21 may have a propagation path offset due to the difference in the spatial phase distribution of light of different wavelengths, resulting in wavelength-dependent dispersion of the focusing position of the encoded light beam on the detection element 22. An achromatic lens element 92 is provided in the optical path between the encoding element 21 and the detection element 22 for chromatic aberration correction of the encoded light beam. Specifically, through its specially designed refractive index distribution and curved surface structure, the achromatic lens can apply differential phase compensation to light of different wavelengths, so that all wavelength components converge to the same focal spot area on the receiving plane of the detection element 22, enabling the detection element 22 to completely capture the spatial intensity distribution information of the encoded light beam, avoiding signal blurring or intensity attenuation caused by dispersion, and thus improving the accuracy of spectral reconstruction and the signal-to-noise ratio.

[0145] As Figures 6 to 9 shown, in some exemplary embodiments, the detection unit 2A further includes: a collimating element 91, disposed between the encoding element 21 and the detection element 22, and the collimating element 91 is located on the optical path of the split light beam for correcting the propagation characteristics of the encoded split light beam.

[0146] In a specific embodiment, the collimating element 91 can be a parabolic mirror or a lens group. When the encoded light beam diverges due to the phase modulation of the encoding element 21 or the propagation path, the collimating element 91 converts the divergent light beam into a parallel light beam through reflection or refraction, eliminating the problem of the expansion of the light beam cross-section with the propagation distance, ensuring the integrity of the spatial intensity distribution information of the encoded light beam when it reaches the detection element 22. At the same time, in the embodiment where the collimating element 91 is a parabolic mirror, the divergent encoded light beam can also be reflected into parallel light through its curved surface design, avoiding the loss of signals at the edge of the detection element 22 due to beam diffusion.

[0147] In another specific embodiment, the collimating element 91 can be a cascaded structure of at least two parabolic mirrors. The first mirror collimates the divergent light beam into a parallel light beam, and the second mirror scales down the parallel light beam proportionally, so that the cross-sectional size of the encoded light beam when it reaches the detection element 22 is smaller than the receiving aperture of the detection element 22. By compressing the spatial distribution density of the light field, it is ensured that the energy of the encoded light beam is concentrated into the receiving aperture of the detection element 22, avoiding problems such as signal attenuation or noise interference caused by beam overflow. Through the propagation correction design of the collimating element 91 in this embodiment, the problem of loss of spatial information of the encoded light beam due to divergence or size mismatch is solved, and the measurement accuracy of weak signals or high-dynamic-range spectra is significantly improved.

[0148] As Figure 6 、 Figure 7 、 Figure 9As shown, in some exemplary embodiments, the spectral measurement device further includes: a pump light input component 6 for receiving an external pump pulse beam; the sample reaction component 5A further has a third window 53, and the third window 53 is for the pump pulse beam to pass through and be incident on the sample to be measured in the reaction chamber to excite the sample to be measured.

[0149] Specifically, in some embodiments, the pump pulse beam can be femtosecond laser or terahertz pulse. The pump light input component 6 is used to receive an external pump pulse beam and guide the pump pulse beam to the third window 53 of the sample reaction component 5A. The third window 53 is an optical transmission window, allowing the pump pulse beam to penetrate and be incident on the surface of the sample to be measured in the reaction chamber, so as to excite the sample to a specific excited state through photothermal, photoelectric or photochemical effects. In this embodiment, the pump pulse beam and the probe beam act on the sample synchronously or asynchronously in time or space. In one embodiment, the pump pulse can also be delayed and controlled by an electrical delay module to first excite the sample, and then the probe beam captures the dynamic response characteristics of the sample under transient excitation. In this embodiment, the outgoing beam carrying the excitation response information is output to the beam splitting element 1A through the second window 52A. After beam splitting and spectral measurement, the ultra-wideband transient spectrum of the sample in the excited state can be reconstructed. This design expands the functional boundary of the device through the synergistic effect of the pump light and the probe light, making it compatible with the requirements of steady-state and transient spectral analysis.

[0150] Those skilled in the art can understand that the features described in the various embodiments of the present disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features described in the various embodiments of the present disclosure can be combined and / or combined in various ways. All such combinations and / or combinations fall within the scope of the present disclosure.

[0151] The above describes the embodiments of the present disclosure. However, these embodiments are only for illustrative purposes and not for limiting the scope of the present disclosure. Although the above embodiments are described separately, this does not mean that the measures in each embodiment cannot be used advantageously in combination. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and all these substitutions and modifications should fall within the scope of the present disclosure.

Claims

1. A spectral measurement method, characterized in that, The method includes: Spatially superposing at least two sub-beams radially along the beam propagation direction to form a combined beam, wherein the total spectral range of the at least two sub-beams continuously covers the target spectral interval; Irradiating the combined beam onto a sample to be measured to obtain an incident beam with the response information of the sample to be measured; Performing radial spatial decoupling beam splitting on the incident beam to obtain at least two split beams, wherein the spectral ranges of the at least two split beams respectively correspond to and are consistent with the spectral ranges of the at least two sub-beams; Measuring the spectral information of each of the split beams respectively.

2. The spectral measurement method according to claim 1, wherein The spatially superposing at least two sub-beams radially along the beam specifically includes: Spatially superposing the at least two sub-beams in a coaxial nested structure so that in the combined beam, the at least two sub-beams are distributed radially outward from the beam center along the beam propagation direction.

3. The spectral measurement method according to claim 2, characterized in that The spatially superposing the at least two sub-beams in a coaxial nested structure includes: Performing beam shrinking and collimation processing on one of the sub-beams to form a reference sub-beam located at the center of the combined beam; Performing beam expanding and collimation processing on the remaining sub-beams to form peripheral sub-beams, and arranging the peripheral sub-beams to successively surround the outer periphery of the reference sub-beam.

4. The spectral measurement method according to claim 2 or 3, characterized in that, The method further includes: Performing focusing processing on the combined beam so that the focused combined beam forms a spatial focus at the sample to be measured.

5. The spectral measurement method according to claim 4, wherein The method further includes: Performing beam expanding and collimation processing on the incident beam so that the beam-expanded and collimated incident beam can be radially spatially decoupled and split into at least two split beams.

6. The spectroscopic measurement method according to claim 3, characterized in that The radial spatial decoupling beam splitting specifically includes: Performing radial reverse separation processing on the incident beam with a coaxial nested structure so that the spectral ranges of the separated split beams are consistent with the spectral ranges of the sub-beams at the corresponding nested positions in the combined beam.

7. The spectroscopic measurement method according to claim 6, wherein The reference sub-beam is an infrared beam in the near-infrared to far-infrared band, and the method further includes: Performing beam expanding and collimation processing on the split beam corresponding to the reference sub-beam to form a reference split beam; Performing transmission-reflection beam splitting processing on the reference split beam to form a first split beam for measuring the near-infrared to mid-infrared band and a second split beam for measuring the far-infrared band.

8. The spectral measurement method according to claim 6 or 7, characterized in that, The peripheral sub-beams are terahertz beams, and the method further includes: Performing collimation processing on the split beams corresponding to the peripheral sub-beams to form peripheral split beams for measuring the terahertz band.

9. The spectral measurement method according to claim 6, characterized in that, The method for obtaining the spectral information of each of the split beams includes: Performing spectral encoding processing on each of the split beams to generate encoded beams having a match with the spectral range of the corresponding sub-beam and carrying spatial phase characteristics; Performing identification processing on each of the encoded beams to obtain the spectral information of each of the split beams.

10. The spectral measurement method according to claim 9, characterized in that, The method further includes: Performing spectral range screening processing on each of the split beams so that the spectral ranges of the split beams entering the spectral encoding are consistent with their corresponding preset encoded spectral ranges.

11. The spectral measurement method according to claim 6, characterized in that The method further includes: Based on the spectral range continuity of the at least two split light beams, data fusion of the overlapping region is performed on the at least two pieces of spectral information to generate continuous spectral information carrying the response information of the sample to be measured and covering the target spectral range.

12. The spectral measurement method according to any one of claims 1-3, 5-7, 9-11, characterized in that, The method further includes: When the combined light beam is irradiated onto the sample to be measured, the pump light beam is irradiated onto the sample to be measured with a fixed pulse, so that the incident light beam is attached with the response information of the sample to be measured in the excited state; Based on the incident light beam, radial spatial decoupling beam splitting is performed to obtain at least two split light beams; The spectral information of each of the split light beams is measured respectively.

13. The spectral measurement method according to claim 12, wherein The step of measuring the spectral information of each of the split light beams respectively includes: Collecting first spectral information at the moment when the pump light beam first excites the sample to be measured; In the subsequent N - 1 pump pulse periods, spectral information is collected with a preset time interval increased in sequence for delay, where the total delay of the Nth collection is equal to the duration of a single pump pulse period, and N is a positive integer greater than 2.

14. The spectral measurement method according to claim 12, characterized in that, The method further includes: Receiving a test light beam generated by an external test light source, performing radial spatial decoupling beam splitting processing on the test light beam to obtain at least two split light beams, and measuring the spectral information of each of the split light beams respectively.

15. A spectral measurement device, characterized in that, It includes: A light beam input component, configured to radially spatially superpose at least two sub - light beams along the optical axis to form a combined light beam, where the total spectral range of the at least two sub - light beams continuously covers the target spectral range; A sample reaction component, provided with a first optical window and a second optical window opposed to each other along the optical axis. The combined light beam is incident on the action area of the sample to be measured through the first optical window, and the second window is used for outputting the incident light beam formed after acting on the sample to be measured; A light beam detection component, the light beam detection component includes: A beam splitting element, which separates the incident light beam into at least two split light beams according to the radial distribution, where the spectral ranges of the at least two split light beams respectively correspond to and are consistent with the spectral ranges of the at least two sub - light beams; At least two detection parts, each of the detection parts is respectively arranged in the optical path of the corresponding split light beam, and is used to obtain the spectral information within the spectral measurement range of each of the split light beams.

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