Composite optical filter based on metasurface and antireflection film system and fluorescence analysis device

Abstract

The utility model relates to a composite optical filter based on a metasurface and an antireflection film system and a fluorescence analysis device, and belongs to the field of optical devices. The composite optical filter modulates incident wide-spectrum light into transmission peaks with two central wavelengths; the super-structure surface layer and the anti-reflection film layer are arranged on the upper surface and the lower surface of the substrate respectively, the super-structure surface layer is designed through a specific micro-nano structure, cut-off in a wide wavelength range is achieved, the anti-reflection film layer is a multi-layer dielectric film or a multi-layer super-structure surface layer, and high transmission in the wide wavelength range is achieved; the metasurface layer is composed of a plurality of metasurface units arranged periodically, any metasurface unit is composed of a metasurface unit substrate and a micro-nano structure arranged on the metasurface unit substrate, and accurate regulation and control of the amplitude, the phase and the polarization characteristic of incident light are achieved by designing the shape of the micro-nano structure. According to the composite optical filter provided by the invention, through the combined action of the super-structure surface and the antireflection film system, high-pass filtering of two wavelengths can be realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of optical devices, and particularly relates to a composite filter based on a super-structured surface and an antireflection film system and a fluorescence analysis device. BACKGROUND

[0002] As a common optical device, a filter is often used to select a specific radiation band. According to spectral characteristics, filters can be classified into band-pass filters and cut-off filters, etc. The application fields of filters are very wide. In the field of photography, filters are often used for color correction, contrast and saturation adjustment, etc.; in the field of industry, filters are often used in machine vision, laser cutting, environmental detection, etc.; in the field of medicine, filters are often used in some laser protection and various cosmetic or analysis instruments such as fluorescence analysis.

[0003] Some application fields of filters, such as fluorescence analysis, need to modulate the incident polychromatic light to form a narrow-band high-pass filter at two wavelengths, so that different fluorescent reagents can be excited. At this time, a filter with a dual-wavelength high-pass narrow-band filtering function is generally needed to realize the filtering modulation of polychromatic light.

[0004] However, the filter with the dual-wavelength high-pass narrow-band filtering function often needs to be coated with multiple layers, and the film layer structure is very complex, and the requirements for the coating process are high. CONTENT OF THE INVENTION

[0005] The present application provides a composite filter based on a super-structured surface and an antireflection film system and a fluorescence analysis device to at least solve the above technical problems in the prior art.

[0006] The present application provides a composite filter based on a super-structured surface and an antireflection film system, which modulates the incident wide-spectrum light into two center-wavelength transmission peaks. The composite filter is composed of a transparent substrate and a super-structured surface layer and an antireflection film layer arranged on the upper and lower surfaces of the substrate, respectively. The super-structured surface layer is designed with specific micro-nano structures to achieve cut-off in a wide wavelength range, and the antireflection film layer is selected from a multi-layer dielectric film or a multi-layer super-structured surface layer to achieve high transmission in a wide wavelength range. The super-structured surface layer is composed of a plurality of periodically arranged super-structured surface units, and any super-structured surface unit is composed of a super-structured surface unit substrate and micro-nano structures arranged on the super-structured surface unit substrate. The shape of the micro-nano structures is designed to precisely control the amplitude, phase and polarization characteristics of the incident light.

[0007] In an implementable manner, the lateral dimension of any super-structured surface unit is in the sub-wavelength range, i.e. P x and P y are in the sub-wavelength range.

[0008] In an implementation, the micro-nano structure occupies a duty cycle of the entire super-structured surface unit.

[0009] In an implementation, the micro-nano structure has a shape of one or more of a cylinder, an elliptic cylinder, a rectangular column, and a square column.

[0010] In an implementation, the peak transmittance of the transmission peak is greater than 80%.

[0011] In an implementation, the bandwidth of the transmission peak satisfies a full width at half maximum (FWHM) less than 30 nm.

[0012] In an implementation, a cutoff region other than the transmission peak has a transmittance less than 0.1%.

[0013] In an implementation, the antireflection film layer is an interference filter, and the antireflection is achieved by reflection, refraction, and interference.

[0014] Another aspect of the embodiments of the present application provides a fluorescence analysis device, including any of the composite filters described above.

[0015] In an implementation, the device further includes a laser light source configured to emit excitation light in a visible light, near-infrared, or mid-infrared waveband; a sample chamber having a light-transmitting window and disposed on an exit light path of the laser light source; a first filter assembly including the composite filter and disposed between the excitation light source and the sample chamber; a second filter assembly disposed on an exit light path of the sample chamber; a photodetector configured to receive a light signal; and a signal processing unit electrically connected to the photodetector.

[0016] Compared with the prior art, the present application has the following advantages:

[0017] The present application breaks through the performance limitation of a single structure by synergistic regulation of the super-structured surface layer and the antireflection film layer, and realizes high-pass filtering of two wavelengths. Meanwhile, the antireflection film layer can also be replaced by a plurality of super-structured surface layers. Compared with a filter made by a conventional multi-layer coating process, the composite filter of the present application has a simple film layer structure, can reduce the requirement for the coating process, and can reduce the cost. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 FIG. 1 is a structural schematic diagram of a composite filter in embodiments of the present application;

[0019] Figure 2 FIG. 2 is a structural schematic diagram of a super-structured surface unit in embodiments of the present application;

[0020] Figure 3 FIG. 3 is a structural schematic diagram of another super-structured surface unit in embodiments of the present application;

[0021] Figure 4A spectral response curve diagram of the super-structured surface layer in the embodiment of the application;

[0022] Figure 5 A spectral response curve diagram of the anti-reflection film layer in the embodiment of the application;

[0023] Figure 6 A spectral response curve diagram of the composite optical filter in the embodiment of the application;

[0024] 1. A composite optical filter; 10, a substrate; 11, a super-structured surface layer; 12, an anti-reflection film layer; 110, a super-structured surface unit; 111, a substrate of the super-structured surface unit; 112, a micro-nano structure. DETAILED DESCRIPTION

[0025] The application will be further described in detail below with reference to the accompanying drawings.

[0026] In the description of the application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0027] Reference Figure 1 The application discloses a composite optical filter based on a super-structured surface and an anti-reflection film system, which can modulate the incident wide-spectrum light into two center-wavelength transmission peaks, the peak transmittance of the transmission peaks is greater than 80%, and the bandwidth of the transmission peaks satisfies FWHM (Full Width Half Maximum) less than 30nm. The transmittance of the cutoff region other than the transmission peaks is less than 0.1%, i.e. the OD (Optical Density) is less than 3.

[0028] The composite optical filter proposed in the application has a working wavelength band including but not limited to the visible light band (380nm-780nm), the near-infrared band (780nm-2500nm) and the mid-far infrared band (2.5um-300um).

[0029] The composite optical filter 1 is composed of a transparent substrate 10, a super-structured surface layer 11 arranged on the upper surface of the substrate 10 and an anti-reflection film layer 12 arranged on the lower surface of the substrate 10. The thickness of the substrate 10 is generally in the nanometer level, while the thickness of the super-structured surface layer 11 and the anti-reflection film layer 12 is generally in the hundred-nanometer to micrometer level.

[0030] The metasurface layer 11, through a specific micro / nano structure design, can achieve cutoff over a certain wide wavelength range. The antireflective coating layer 12, achieved through conventional coating methods, can achieve high transmittance over a certain wide wavelength range. Furthermore, the antireflective coating layer 12 can also be implemented using a multilayer metasurface layer approach to achieve high transmittance over a wide wavelength range.

[0031] refer to Figure 2 The metasurface layer 11 is composed of several periodically arranged metasurface units 110. Each metasurface unit 110 consists of a metasurface unit substrate 111 and a micro / nano structure 112 disposed on the metasurface unit substrate. Precise control of the amplitude, phase, and polarization characteristics of the incident light is achieved by designing the shape of the micro / nano structure 112. The lateral dimension of each metasurface unit 110 is in the subwavelength range, i.e., P... x and P y In the subwavelength range, there is a duty cycle between the area occupied by the micro / nano structure 112 and the area of ​​the entire metasurface unit 110. The shape of the micro / nano structure 112 includes, but is not limited to, cylinders, elliptical cylinders, rectangular cylinders, and square cylinders.

[0032] The ratio of the area occupied by the micro / nano structure 112 to the area occupied by the entire metasurface unit 110 is the duty cycle F. Figure 3 In the metasurface unit 110 shown, the following is observed:

[0033]

[0034] Where S is the area of ​​the cross-section of the micro / nano structure 112. For example, when the cross-section of the micro / nano structure 112 is a rectangular prism or a square prism, then...

[0035] S = D x *D y

[0036] By specifically designing the micro / nano structure 112, precise control of the amplitude, phase, and polarization characteristics of incident light can be achieved.

[0037] Taking the visible light band as an example, the working principle of the composite filter of this application is explained. In this embodiment, the working range of the composite filter is the visible light band (380nm-780nm), so the range of its lateral dimensions is approximately 190nm-390nm.

[0038] In this embodiment, the design method of the micro / nano structure 112 is specifically as follows: A model of the micro / nano structure 112 is established using electromagnetic simulation software such as FDTD; the structural parameters of the micro / nano structure 112, such as P... x P y D x D y F and h are set as optimization variables and boundaries are set, for example, Px and P y Generally, the sub-wavelength scale, the duty cycle F is usually less than 0.8; using PSO (Particle Swarm Optimization) algorithm, optimization. The final optimization goal as shown in Figure 4 The entire broadband 300nm to 900nm wavelength of incident light, as shown in the wavelength 500nm to 700nm, showing a high transmission.

[0039] The antireflection film layer 12 can be a commonly used optical film, such as an interference filter, which reduces reflection and increases transmission by reflection, refraction and interference. As shown in Figure 5 The entire broadband 300nm to 900nm wavelength of incident light, as shown in the wavelength 440nm to 760nm, showing a high transmission.

[0040] The entire composite filter 1 to the entire broadband 300nm to 900nm wavelength of incident light as shown in Figure 6 The effect of the entire composite filter 1 to the entire broadband 300nm to 900nm wavelength of incident light as shown in

[0041] The application also discloses a fluorescence analysis device, which comprises a laser light source, a sample chamber, a first filter assembly, a second filter assembly, a photodetector and a signal processing unit. The laser light source is used for emitting excitation light in a visible light, near-infrared or mid-infrared wave band. The sample chamber is provided with a light-transmitting window and is arranged on an outgoing light path of the laser light source. The photodetector is used for receiving a light signal. The signal processing unit is electrically connected with the photodetector. The first filter is selected from any one of the composite filters, and is arranged between the excitation light source and the sample chamber. The second filter assembly can be selected from any one of the composite filters or a traditional filter assembly.

[0042] Taking the visible light wave band as an example, the fluorescence analysis device in the embodiment realizes efficient fluorescence detection through the composite filter:

[0043] The excitation light source is selected from 475nm wavelength excitation light. After the first filter assembly (i.e. the composite filter) filters out stray light with a wavelength of 350-460nm and 490-650nm, the pure excitation light is incident on the sample chamber. The sample chamber is provided with a fluorescent marker. The excitation light induces fluorescent light with a wavelength of 600nm. The second filter assembly blocks stray light and only allows fluorescent light with a wavelength of 600nm to pass through the photodetector. The signal processing unit converts the photoelectric signal into fluorescence intensity data, thereby realizing quantitative analysis of substances.

[0044] The above merely describes specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present disclosure, which should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A composite filter based on a metasurface and an antireflection film system, characterized in that: The composite filter modulates the incident broadband light into two center wavelength transmission peaks; It is composed of a transparent substrate, a super-structured surface layer and an antireflection film layer arranged on the upper and lower surfaces of the substrate respectively. The super-structured surface layer is designed with specific micro-nano structures to achieve cut-off in a wide wavelength range, and the antireflection film layer is selected from a multi-layer dielectric film or a multi-layer super-structured surface layer to achieve high transmission in a wide wavelength range. The super-structured surface layer is composed of a plurality of periodically arranged super-structured surface units, and any super-structured surface unit is composed of a super-structured surface unit substrate and micro-nano structures arranged on the super-structured surface unit substrate. The shape of the micro-nano structure is designed to precisely control the amplitude, phase and polarization characteristics of the incident light.

2. The compound filter according to claim 1, characterized in that: The lateral dimension of any hyper-surface unit is in the sub-wavelength range, i.e. P x and P y in the sub-wavelength range.

3. The compound filter of claim 1, wherein: The area occupied by the micro-nano structure and the area of the entire super-structured surface unit have a duty cycle.

4. The compound filter of claim 1, wherein: The shape of the micro-nano structure is one or more of a cylindrical, elliptical cylindrical, rectangular cylindrical and square cylindrical shape.

5. The compound filter of claim 1, wherein: The peak transmittance of the transmission peak is greater than 80%.

6. The compound filter of claim 1, wherein: The bandwidth of the transmission peak satisfies FWHM less than 30nm.

7. The compound filter of claim 1, wherein: The cut-off region outside the transmission peak has a transmittance less than 0.1%.

8. The compound filter of claim 1, wherein: The antireflection film layer selects an interference filter to achieve antireflection by reflection, refraction and interference.

9. A fluorescence analysis device, characterized by: It comprises the composite filter of any one of claims 1-8.

10. The fluorescence analysis apparatus according to claim 9, characterized by It further comprises: A laser light source for emitting excitation light in the visible, near-infrared or mid-infrared wavelength band; A sample chamber provided with a light-transmitting window and arranged on the exit light path of the laser light source; A first filter assembly using the composite filter and arranged between the excitation light source and the sample chamber; A second filter assembly arranged on the exit light path of the sample chamber; A photodetector for receiving optical signals; A signal processing unit electrically connected to the photodetector.

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