A spectral measurement component with high resolution and a far-field spectral measurement method

Abstract

This invention discloses a high-resolution spectral measurement device and a far-field spectral measurement method. The measurement device includes a silicon dioxide substrate, alternating high and low refractive index photonic crystal layers, a high refractive index modulation layer, and a low refractive index defect layer. After the far-field light source under test excites Bloch surface waves on the surface of the device, a CCD imaging device records the reflected light signal. Then, the environment on the surface of the device is changed, and the reflected light signal is recorded again. Based on the difference results of the two signals, the relative intensity distribution at different spatial locations is obtained. Then, based on the specific geometric positional relationship between the CCD imaging device and the device, and the dispersion relationship of the device's own structure, the relative intensity distribution at different spatial locations is converted into a relative intensity relationship between wavelengths, i.e., the spectrum of the far-field light source under test. The device structure described in this invention is compact and easily expandable, and the method has high light source signal utilization and good noise resistance.

Description

Technical Field

[0001] This invention relates to the fields of optical chips and spectral detection, and in particular to a high-resolution spectral measurement device and a far-field spectral measurement method. Background Technology

[0002] In industrial production, materials science, biomedicine, and other related applications, spectral detection has become a widely used and mature technology, possessing characteristics such as high speed and non-destructive properties, thus broadening the application scenarios of many research areas. In environmental monitoring, during various spectral imaging processes, the spectrum can characterize probe signals under different environments, enabling the analysis of local physical and chemical properties. In the fields of microscopy and molecular biology, it can rapidly complete detection and qualitative and quantitative analysis, helping to identify and elucidate various biological processes. With the expansion of applications and the improvement of functions, spectral detection is no longer limited to laboratory processing and analysis. More outdoor applications, such as high-speed detection in complex environments and remote sensing measurements under interference conditions, are placing demands on the portability of spectral detection instruments. Therefore, the development of spectrometers is moving towards miniaturization, high spectral resolution, and high acquisition speed. Integrated miniature spectrometers thus have even broader application prospects.

[0003] Today, with the development of nanophotonics, there are various methods to achieve miniaturization of spectral detection. Researchers use ultra-small micro-nano structures and the solution of linear equations to complete the inversion calculation of spectra. By using techniques such as electrical signal modulation, optical signal modulation or mode modulation, the superposition results of different modulation signals are measured, and then the inversion matrix corresponding to the designed structure is combined with the optimized inversion algorithm to complete the inversion of the initial spectrum. The cascade of spectral measurement range is completed by designing intricate in-plane micro-nano structures and ultra-fine filtering elements to complete the spectral screening. Recently, the spectral detection device based on the Tamm structure is only micrometer in size, and can be conveniently applied to imaging microscopes while detecting near-field spectra; and then the spectral detection device based on nanowires further compressed the spectral detection element to the micrometer or even nanometer scale, breaking the record for the smallest size spectrometer. However, the main problems of the above-mentioned existing spectral detection devices are: (1) The equipment is large and the processing is complex. The high spectral resolution of traditional spectrometers depends on the dispersion ability of the dispersive element itself. In order to ensure a sufficiently high spectral resolution, the size and accuracy of the device are extremely high. While miniature spectrometers reduce the size of dispersive elements, they require complex and cumbersome processing methods and technologies. (2) Low utilization of light source signals: As a necessary component in dispersive spectrometers, the slit ensures the resolution of the spectrometer but limits the light transmission of the light source under test, thereby reducing the light transmission capacity and signal-to-noise ratio. (3) Slow speed: Fourier transform spectrometers improve spectral resolution by increasing the optical path difference, which requires a certain acquisition time and cannot meet the needs of rapidly changing dynamic spectral measurements. (4) Susceptible to interference: Existing computational spectral analysis methods based on spectral inversion are highly dependent on the initial conditions of the measurement, are easily affected by noise signals, have long computation time, and have large errors in the inversion results. (5) Insufficient resolution: Existing conventional portable spectrometers reduce the size of the device to meet the requirements of portability, but sacrifice spectral resolution, making it difficult to complete high-precision optical measurements outdoors and under harsh conditions. (6) Limited spectral measurement range: Existing dispersive spectral measurement technologies are mostly designed for light signals within the visible light range. For light signals in the ultraviolet and infrared ranges, additional specialized dispersive elements are required, resulting in limited product versatility. (7) High equipment cost and limited scalability: Large, specialized dispersive elements are expensive, leading to high maintenance costs. Furthermore, once the equipment is installed and debugged, it is difficult to add new optical elements. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a high-resolution spectral measurement device and a far-field spectral measurement method for identifying samples and characterizing materials.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A high-resolution spectral measurement device comprises, in the thickness direction, a silicon dioxide substrate layer, an alternating high and low refractive index photonic crystal layer, a high refractive index modulation layer, and a low refractive index defect layer.

[0007] Furthermore, the spectral measurement device can be attached to any type of optical path to achieve the excitation of Bloch surface waves.

[0008] Furthermore, the thickness of the low-refractive-index defect layer is less than 0.5 micrometers.

[0009] Furthermore, the thickness of the alternating high and low refractive index photonic crystal layer does not exceed 2 micrometers.

[0010] Furthermore, the high-refractive-index material in the alternating high- and low-refractive-index photonic crystal layer is silicon nitride, the low-refractive-index material is silicon dioxide, the material of the high-refractive-index modulation layer is silicon nitride, and the material of the low-refractive-index defect layer is silicon dioxide.

[0011] Furthermore, after the Bloch surface wave on the spectral measurement device is excited by the far-field light source under test, the reflected light signal is recorded. Then, the environment on the surface of the device is changed, and the reflected light signal is recorded again. Based on the difference between the two signals, the relative intensity distribution at different locations in space is obtained. The relative intensity distribution at different locations in space is converted into the relative intensity relationship between wavelengths, which is the spectrum of the far-field light source under test.

[0012] According to the far-field spectral measurement method described above, the method specifically includes the following steps:

[0013] Step 1: The spectral measurement device is attached to the prism. The light emitted by the far-field light source is focused onto the oblique side of the prism by the beam expander, polarizer, and front cylindrical lens to excite the Bloch surface wave on the spectral measurement device. The far-field light source is incident from the lower surface of the device, i.e. the silicon dioxide substrate layer, and excites the Bloch surface wave of the low refractive index defect layer on the upper surface of the device. The reflected light is then collected by the CCD imaging device after passing through the rear cylindrical lens, and the relative intensity distribution of the reflected light in space is recorded.

[0014] Step 2: Change the environmental distribution on the surface of the spectral measurement component, repeat Step 1, collect the reflected light signal again using the CCD imaging device, and record the relative intensity distribution of the reflected light in space again;

[0015] Step 3: Perform differential analysis on the two collected reflected light signals, and convert the relative intensity distribution at different locations in space into relative intensity distribution at different angles based on the geometric positional relationship of the optical elements. Then, based on the dispersion relationship of the designed spectral measurement device, convert the relative intensity distribution at the angles into relative intensity distribution at different wavelengths, i.e., the spectrum of the far-field light source.

[0016] Furthermore, in step two, the environmental distribution on the surface of the spectral measurement component is changed so that the refractive index of the environment above the surface of the spectral measurement component changes by more than 0.2, and the recovery time is less than the order of milliseconds.

[0017] Furthermore, the thickness parameter of the alternating high and low refractive index photonic crystal layer can be used to adjust the range of the measured spectrum. When the relative refractive indices of the high and low refractive index layers are similar, the measurement range is the widest. The thicker the unit structure of the alternating high and low refractive index photonic crystal layer, the more the measured spectrum tends to be redshifted.

[0018] Furthermore, the thickness of the high refractive index modulation layer and the low refractive index defect layer can be used to adjust the spectral resolution of the measured spectrum. When the wavelength range of the light source to be measured is determined, the corresponding Bloch surface wave excitation angle is brought close to the critical angle by adjusting the thickness of the high refractive index modulation layer and the low refractive index defect layer, thereby achieving the optimal spectral resolution.

[0019] This invention utilizes chip structural design to tailor and modulate its own dispersion curve, linearly corresponding the wavelength of the excited Bloch surface waves to the excitation angle. By altering the chip surface environment, it records the spatial intensity distribution at different times. Then, leveraging the geometric relationship between the dispersion curve and optical elements, it simply converts the spatial differential relative intensity distribution into relative intensity distributions in terms of angle and wavelength, thus completing the spectral detection of the far-field light source. Its compact size, low noise resistance, low cost, high spectral resolution, and lack of complex inversion algorithms make it easily integrateable into existing mature technologies, such as quality inspection platforms, high-resolution sensors, and biomedical analyzers. It can even be extended to applications in space telescopes or optical microscopes.

[0020] This invention utilizes spectral measurement components and simple unit conversions to complete the measurement of far-field spectra without inversion calculations.

[0021] Compared with the prior art, the advantages of the present invention include:

[0022] (1) Compact structure and simple processing: The thickness of the spectral measurement components is generally no more than 2 micrometers, and the in-plane size is only the size of the focused spot, which meets the portability requirements of the miniature spectrometer. At the same time, the layered structure is only distributed in the longitudinal direction, and the processing method is relatively simple.

[0023] (2) No slit required, high signal utilization: The spectral measurement components complete the clipping and modulation of their own dispersion curves based on their structure, and the spectral inversion process does not depend on the selection of the slit. Therefore, the signal of the light source under test can be fully utilized, resulting in high efficiency, high signal-to-noise ratio, and the ability to perform spectral detection of weak signals.

[0024] (3) Fast response speed: The spectral measurement components realize spectral detection and characterization only through unit conversion, which reduces the calculation time of various calculations in the optimization and inversion algorithm process, and the control signal recovery time is short, ensuring the rapid measurement of differential signals.

[0025] (4) High noise immunity and high signal-to-noise ratio: The spectral measurement components do not require inversion calculations during the spectral measurement process, have low requirements for the initial conditions during detection, are less affected by noise, and have excellent noise immunity. At the same time, differential signal extraction based on surface environment control can extract the reflection signal containing the spectral information of the light source under test from a complex and non-uniform background, which is not easy to observe, thereby improving the contrast and signal-to-noise ratio of the detection results.

[0026] (5) High spectral resolution: The size of the spectral measurement components has been reduced, but the spectral inversion approach is still based on the traditional spectrometer principle. Unlike the traditional spectrometer principle, the high spectral resolution measurement of far-field spectra can be achieved based on the low loss and high linearity of Bloch surface waves.

[0027] (6) Measurement wavelength range with controllable accuracy: The spectral measurement components utilize the thickness relationship between each layer to achieve spectral detection of different wavelength ranges, as well as high-resolution detection of the required wavelength range.

[0028] (7) Low cost and good scalability: The microfabrication process can be completed through vapor deposition without etching and processing of in-plane microstructures. It is inexpensive and easy to mass-produce. Moreover, the ultra-thin nature of the spectral measurement components can be easily attached to traditional optical paths to achieve both imaging analysis and spectral detection, which is convenient for observing biological and chemical processes. At the same time, the spectral measurement components do not contain metal materials, have good biocompatibility, and are easy to clean and reuse.

[0029] In addition to the features and advantages described above, the invention also possesses other principles, features, and advantages. The invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the high-resolution spectral measurement component of the present invention.

[0031] Figure 2 This diagram illustrates a far-field spectral measurement method utilizing spectral measurement components.

[0032] Figure 3 The graph shows the dispersion curve of the spectral measurement device, as well as the spectral detection results of the low-pressure sodium lamp and rhodamine solution using this device.

[0033] Figure 4The graph shows the dispersion curve of the spectral measurement device, as well as the spectral detection results of Raman spectra of far-field white light sources and organic solvents using this device.

[0034] Figure 5 This is a schematic diagram showing the one-to-one correspondence between the excitation angle of Bloch surface waves and the position of the signal recorded on the CCD imaging device. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The implementation of this invention will be described in detail below with reference to specific embodiments.

[0036] Example 1:

[0037] like Figure 1 As shown, a high-resolution spectral measurement device includes a silicon dioxide substrate layer 1, alternating high and low refractive index photonic crystal layers 2, a high refractive index modulation layer 3, and a low refractive index defect layer 4. When a Bloch surface wave on the spectral measurement device is excited by a far-field light source under test, the reflected light signal is recorded. Then, the environment on the surface of the device is changed, and the reflected light signal is recorded again. Based on the difference between the two signals, the relative intensity distribution at different spatial locations is obtained. Then, based on the geometric positional relationship of the optical elements and the dispersion relationship of the device's own structure, the relative intensity distribution at different spatial locations is converted into the relative intensity relationship between wavelengths, i.e., the spectrum of the far-field light source under test.

[0038] Furthermore, the high-resolution spectral measurement device can be attached to any type of conventional optical path to achieve the excitation of Bloch surface waves.

[0039] Furthermore, the layers of the high-resolution spectral measurement device can be achieved through plasma-enhanced chemical vapor deposition.

[0040] Furthermore, the low-refractive-index defect layer 4 of the high-resolution spectral measurement device is made of silicon dioxide with a thickness of approximately 0.15 micrometers.

[0041] Furthermore, the thickness of the alternating high and low refractive index photonic crystal layer 2 of the high-resolution spectral measurement device is approximately 1.2 micrometers.

[0042] Furthermore, in the high-refractive-index alternating photonic crystal layer 2 of the high- and low-refractive-index spectral measurement device, the high-refractive-index material is silicon nitride with a thickness of approximately 0.08 micrometers, and the low-refractive-index material is silicon dioxide with a thickness of approximately 0.125 micrometers. The high-refractive-index modulation layer 3 is also made of silicon nitride with a thickness of approximately 0.08 micrometers. Therefore, the measurement range of this spectral measurement device is 550 nm–610 nm, and its spectral resolution is less than 0.6 nm.

[0043] The above-mentioned far-field spectral measurement method with high-resolution spectral measurement components includes the following steps:

[0044] Step 1: As Figure 2 The spectral measurement element is attached to the prism 9. The light emitted by the low-pressure sodium lamp (far-field light source 5) is focused onto the oblique side of the prism 9 by the beam expander lens 6, polarizer 7, and front cylindrical lens to complete the excitation of Bloch surface waves on the spectral measurement element. After the light enters from the lower surface of the element, i.e. the silicon dioxide substrate 1, and excites the Bloch surface waves of the low refractive index defect layer 4 on the upper surface of the element, the reflected light is collected by the CCD imaging device 11 after passing through the rear cylindrical lens 10, and the relative intensity distribution of the reflected light in space is recorded.

[0045] Step 2: Pass a humid airflow through the surface of the spectral measurement device, collect the reflected light signal again using a CCD imaging device, and record the relative intensity distribution of the reflected light in space again.

[0046] Step 3: Perform differential analysis on the two acquired reflected light signals. Convert the relative intensity distribution at different spatial locations into relative intensity distributions at different angles based on the geometric relationships of the optical elements. Then, based on the dispersion relationship of the designed spectral measurement components, such as... Figure 3 Figure (a) in the figure converts the relative intensity distribution at the angle into the relative intensity distribution at different wavelengths, i.e., the spectrum of the far-field light source.

[0047] Using the aforementioned spectral measurement components and simple unit conversions, the far-field spectrum was measured without inversion calculations, and the results are as follows. Figure 3 The solid line in Figure (b) and the dashed line in the figure correspond to the measurement results of the portable commercial spectrometer on the same light source. It can be seen that its resolution is not as good as the spectral measurement device described in this invention.

[0048] The low-pressure sodium lamp was replaced with a rhodamine solution and excited with a 532 nm laser. Steps one through three were then repeated to obtain the emission spectrum of the rhodamine solution, as shown below. Figure 3 The implementation of Figure (c) is shown in the figure. The dashed lines in the figure correspond to the measurement results of the portable commercial spectrometer on the same light source, and it can be seen that the two are basically consistent within their respective measured spectral ranges.

[0049] Example 2:

[0050] like Figure 1 As shown, a high-resolution spectral measurement device includes a silicon dioxide substrate layer 1, alternating high and low refractive index photonic crystal layers 2, a high refractive index modulation layer 3, and a low refractive index defect layer 4. When a Bloch surface wave on the spectral measurement device is excited by a far-field light source, the reflected light signal is recorded. Then, the environment on the device surface is changed, and the reflected light signal is recorded again. Based on the difference between the two signals, the relative intensity distribution at different spatial locations is obtained. Then, based on the geometric positional relationship of the optical elements and the dispersion relationship of the device's own structure, the relative intensity distribution at different spatial locations is converted into a relative intensity relationship between wavelengths, i.e., the spectrum of the far-field light source.

[0051] Furthermore, the high-resolution spectral measurement device can be attached to any type of conventional optical path to achieve the excitation of Bloch surface waves.

[0052] Furthermore, the high-resolution spectral measurement device can be implemented layer by plasma-enhanced chemical vapor deposition.

[0053] Furthermore, in the high-resolution spectral measurement device, the low-refractive-index defect layer 4 is made of silicon dioxide with a thickness of approximately 0.185 micrometers.

[0054] Furthermore, in the high-resolution spectral measurement device, the thickness of the alternating high and low refractive index photonic crystal layer 2 is approximately 1.35 micrometers.

[0055] Furthermore, in the high-resolution spectral measurement device, the high-refractive-index material in the alternating high- and low-refractive-index photonic crystal layer 2 is silicon nitride with a thickness of approximately 0.092 micrometers, and the low-refractive-index material is silicon dioxide with a thickness of approximately 0.135 micrometers. The high-refractive-index modulation layer is also made of silicon nitride with a thickness of approximately 0.09 micrometers. Therefore, the measurement range of this spectral measurement device is 590 nm–710 nm, and its spectral resolution is less than 2 nm.

[0056] The above-mentioned far-field spectral measurement method with high-resolution spectral measurement components includes the following steps:

[0057] Step 1: As Figure 2The spectral measurement element is attached to the prism 9. The far-field white light emitted by the halogen lamp (far-field light source 5) is focused onto the oblique side of the prism 9 by the beam expander lens 6, polarizer 7, and front cylindrical lens 8 to excite the Bloch surface wave on the spectral measurement element. After the light enters from the lower surface of the element, i.e. the silicon dioxide substrate 1, and excites the Bloch surface wave of the low refractive index defect layer 4 on the upper surface of the element, the reflected light is collected by the CCD imaging device 11 after passing through the rear cylindrical lens 10, and the relative intensity distribution of the reflected light in space is recorded.

[0058] Step 2: Pass a humid airflow through the surface of the spectral measurement device, collect the reflected light signal again using a CCD imaging device, and record the relative intensity distribution of the reflected light in space again.

[0059] Step 3: Differentiate the reflected light signals acquired in the two trials, and convert the relative intensity distribution at different spatial locations into relative intensity distributions at different angles based on the geometric positions of the optical elements. Then, based on the dispersion relation of the designed spectral measurement components, such as... Figure 4 Figure (a) in the figure converts the relative intensity distribution at the angle into the relative intensity distribution at different wavelengths, i.e., the spectrum of the far-field light source.

[0060] Using the aforementioned spectral measurement components and simple unit conversions, the far-field spectral measurements were completed without inversion calculations, as shown below. Figure 4 The light-colored line in Figure (b) shows the results. The dark-colored line in the figure corresponds to the measurement results of the portable commercial spectrometer for the same light source, and it can be seen that the two are basically consistent within their respective measured spectral ranges.

[0061] The halogen lamp was replaced with a commonly used organic solution of anhydrous ethanol and dimethyl sulfoxide, and excited with a 532 nm laser. Steps one through three were then repeated to obtain the Raman spectrum of the organic solution, as shown below. Figure 4 Figure (c) in section 4 and Figure (d) in section 4 are shown. The dotted lines represent the fitting results of the signal curves, clearly distinguishing the two Raman peaks in anhydrous ethanol and the three Raman peaks in dimethyl sulfoxide. This also means that the spectroscopic measurement device described in this invention can perform the detection of weak signals and the identification of unknown organic solutions.

[0062] The relevant principles of the technical solution of this invention are as follows:

[0063] By rationally setting and depositing multilayer dielectric films of varying thicknesses, the dispersion curve of the structure itself can be tailored and controlled. Based on the low-loss characteristics of the dielectric film, specific multilayer dielectric films can be fabricated, thereby enabling the excitation of Bloch surface waves and ensuring a one-to-one linear correspondence between wavelength and Bloch surface wave excitation angle, as can be seen from its dispersion curve. The structure exhibiting this dispersion relationship is the spectral measurement device described in this invention, used in the development of miniature spectrometers. Further adjustment of the material and thickness parameters of the defect layer allows light of the same wavelength incident on the dielectric film to have completely different reflection characteristics in air and water environments. By subtracting the signals from the two measurements, the non-uniform background in the reflected signal can be removed, resulting in a background-free signal containing spectral information. Based on these characteristics, after light of different wavelengths is excited by the spectral measurement device to produce Bloch surface waves, its reflected signals will exit at different angles. The distribution of the relative intensity of the reflected signals of different wavelengths is recorded at different spatial locations by a CCD imaging device. Specifically, as shown... Figure 5 As shown, different coupling emission angles α1, α2, α3, ... correspond to different positions x1, x2, x3, ... recorded on the CCD imaging device. Therefore, based on the geometric relationship of the placement of optical components such as the CCD imaging device and spectral measurement devices, the conversion between spatial position and emission angle can be easily completed. That is, there is a one-to-one correspondence between the Bloch surface wave excitation angle and the position recorded on the CCD imaging device. The dispersion curve is an inherent property of the spectral measurement device; once the structure of the spectral measurement device is determined, the dispersion curve is the only one that can be calculated or measured. It shows a one-to-one linear correspondence between wavelength and Bloch surface wave excitation angle, that is, the emission angle corresponds one-to-one with each wavelength of the light source under test, so the conversion between emission angle and wavelength can be further completed. Therefore, the spectrum of the light source under test can be inferred from the differential signal recorded by the CCD imaging device.

[0064] This invention also mentions extracting differential signals by altering the surface environment of spectral measurement components. Due to the rationally designed and fabricated multilayer dielectric film structure, almost only the angle corresponding to the excited Bloch surface wave changes during this process, thus effectively removing complex and non-uniform background signals. This allows for the recording of imperceptible changes in the reflected signal, enabling the direct calculation of the spectrum of the light source under test without inversion operations.

[0065] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A far-field spectral measurement method with a high-resolution spectral measurement device, wherein the spectral measurement device comprises, in the thickness direction, a silicon dioxide substrate layer (1), an alternating high and low refractive index photonic crystal layer (2), a high refractive index modulation layer (3), and a low refractive index defect layer (4). characterized in that The measurement method is as follows: after the Bloch surface wave on the spectral measurement component is excited by the far-field light source under test, the reflected light signal is recorded; then the environment on the surface of the component is changed, and the reflected light signal is recorded again. Based on the difference between the two signals, the relative intensity distribution at different locations in space is obtained, and the relative intensity distribution at different locations in space is converted into the relative intensity relationship between wavelengths, that is, the spectrum of the far-field light source under test.

2. The far field spectroscopic measurement method of a spectral measurement component with high resolution according to claim 1, characterized in that, The spectral measurement device can be attached to any type of optical path to achieve the excitation of Bloch surface waves.

3. The far-field spectral measurement method with high-resolution spectral measurement components according to claim 1, characterized in that, The thickness of the low refractive index defect layer (4) is less than 0.5 micrometers.

4. The far-field spectral measurement method with high-resolution spectral measurement components according to claim 1, characterized in that, The thickness of the alternating high and low refractive index photonic crystal layer (2) is no more than 2 micrometers.

5. The far field spectral measurement method of a spectral measurement component with high resolution according to claim 1, characterized in that, The high refractive index material in the alternating high and low refractive index photonic crystal layer (2) is silicon nitride, the low refractive index material is silicon dioxide, the high refractive index modulation layer (3) is made of silicon nitride, and the low refractive index defect layer (4) is made of silicon dioxide.

6. The method of remote spectroscopic measurement of a spectral measuring cell with high resolution according to any of claims 1 to 5, characterized in that The method specifically includes the following steps: Step 1: The spectral measurement device is attached to the prism (9). The light emitted by the far-field light source (5) is focused onto the oblique side of the prism (9) by the beam expander (6), polarizer (7), and front cylindrical lens (8) to complete the excitation of Bloch surface waves on the spectral measurement device. The far-field light source (5) is incident from the lower surface of the device, i.e. the silicon dioxide substrate layer (1), and excites the Bloch surface waves of the low refractive index defect layer (4) on the upper surface of the device. The reflected light is collected by the CCD imaging device (11) after passing through the rear cylindrical lens (10) to record the relative intensity distribution of the reflected light in space. Step 2: Change the environmental distribution on the surface of the spectral measurement component, repeat step 1, collect the reflected light signal again using the CCD imaging device (11), and record the relative intensity distribution of the reflected light in space again; Step 3: Perform differential analysis on the two collected reflected light signals, and convert the relative intensity distribution at different locations in space into relative intensity distribution at different angles based on the geometric positional relationship of the optical elements. Then, based on the dispersion relationship of the designed spectral measurement device, convert the relative intensity distribution at the angles into relative intensity distribution at different wavelengths, i.e., the spectrum of the far-field light source.

7. The far field spectroscopic measurement method of a spectral measurement component with high resolution according to claim 6, characterized in that, In step two, the environmental distribution on the surface of the spectral measurement component is changed so that the refractive index of the environment above the surface of the spectral measurement component changes by more than 0.2 and the recovery time is less than the order of milliseconds.

8. The far field spectroscopic measurement method of a spectral measurement component with high resolution according to claim 6, characterized in that, The thickness parameter of the alternating high and low refractive index photonic crystal layer (2) can be used to adjust the range of the measured spectrum. When the relative refractive indices of the high and low refractive index layers are similar, the measurement range is the widest. The thicker the unit structure of the alternating high and low refractive index photonic crystal layer (2), the more the measured spectrum tends to be redshifted.

9. The far field spectroscopic measurement method of a spectral measurement component with high resolution according to claim 6, characterized in that, The thickness of the high refractive index modulation layer (3) and the low refractive index defect layer (4) can be used to adjust the spectral resolution of the measured spectrum. When the wavelength range of the light source to be measured is determined, the corresponding Bloch surface wave excitation angle is brought close to the critical angle by adjusting the thickness of the high refractive index modulation layer (3) and the low refractive index defect layer (4), thereby achieving the optimal spectral resolution.

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