A method for amplifying the chiral molecular recognition signal by using an optical microstructure

Abstract

A method for amplifying the chiral molecule recognition signal by using an optical microstructure provided by the present invention includes: irradiating with a linearly polarized light beam from one side in the Z-axis direction of the chiral molecule to be recognized; sequentially arranging an optical microstructure and a fluorescent screen on the other side in the Z-axis direction of the chiral molecule to be recognized; both the optical microstructure and the fluorescent screen are arranged perpendicular to the Z-axis; and recognizing the configuration type of the chiral molecule through the bright and dark states of the fluorescent screen. The present invention adopts a method combining an optical microstructure and a fluorescent screen, amplifies the weak chiral molecule recognition signal by using the polarization selectivity of the optical microstructure for circularly polarized light, and then recognizes the chiral molecule signal by observing the bright and dark states of the fluorescent screen. This method has the characteristics of simple operation, fast response speed, high recognition accuracy and wide application range, and has extremely strong practicability.

Description

Technical Field

[0001] The present invention relates to the field of metasurface devices and chiral molecule recognition, and particularly to a method for amplifying chiral molecule recognition signals by using optical microstructures. Background Art

[0002] Chirality is a structural property and a common phenomenon existing in nature, that is, an object cannot be superimposed on its mirror image through translation or rotation operations. The chiral phenomenon widely exists in nature, and is more common in microscopic systems. For example, organic macromolecules such as DNA, amino acid molecules, and proteins all have chiral structures. Chiral objects and their mirror images are called enantiomers, one of which is the L-type enantiomer and the other is the D-type enantiomer. In pharmacy, more than half of the medical drugs are chiral compounds. More importantly, some drugs can only play the correct role under specific chiral enantiomers. If the wrong chiral enantiomer is selected, completely opposite characteristics may occur. For example, thalidomide, one of the chiral molecules can inhibit pregnancy reactions, while the other can cause fetal malformations. Therefore, the research on the recognition of chiral compounds has important significance and application prospects in medicinal chemistry, drug design, toxicology, etc.

[0003] Traditional methods for recognizing chiral molecules include chromatography, circular dichroism, etc. Optically active substances have circular dichroism. When linearly polarized light passes through a chiral substance, due to the different absorption coefficients of the left-handed circularly polarized light and the right-handed circularly polarized light that make up the linearly polarized light by the chiral substance, that is, chiral molecules usually have different absorption effects on circularly polarized light with a specific degree of rotation. Taking the light wavelength as the abscissa and the difference in absorption coefficients as the ordinate, the circular dichroism spectrum is obtained. Chromatography and spectroscopy have advantages such as good separation effect and high accuracy, but require high sample purity. At the same time, the circular dichroism spectrum test is relatively complex and requires passing through multiple optical instruments to obtain the circular dichroism spectrum. For the doping of trace amounts of different chiral molecules, the light loss is large in this process, and it is difficult to analyze the intensity difference between the left-handed circularly polarized light and the right-handed circularly polarized light on the spectrum, resulting in low recognition accuracy for trace chiral molecules.

[0004] For trace-doped chiral molecules, after a beam of linearly polarized light irradiates the chiral molecules, due to the optical effect of the chiral molecules on the linearly polarized light, the incident linearly polarized light will be transmitted as left-handed or right-handed circularly polarized light but with extremely weak intensity. Therefore, it is difficult to use traditional spectroscopic analysis methods to analyze the intensity of the left-handed or right-handed circularly polarized light to identify the chiral type of chiral molecules. Summary of the Invention

[0005] The object of the present invention is to provide a method for amplifying the chiral molecular recognition signal by using an optical microstructure, aiming at the problem of too low signal intensity of chiral molecular recognition in the prior art. The method has the advantages of simple and intuitive recognition process and fast response speed, and can significantly amplify the recognition signal to achieve accurate recognition of trace-doped chiral molecules.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for amplifying the chiral molecular recognition signal by using an optical microstructure, comprising:

[0008] Irradiate from one side in the Z-axis direction of the chiral molecule to be recognized with a linearly polarized light beam;

[0009] On the other side in the Z-axis direction of the chiral molecule to be recognized, an optical microstructure and a fluorescent screen are sequentially arranged; both the optical microstructure and the fluorescent screen are arranged perpendicular to the Z-axis;

[0010] Identify the configuration type of the chiral molecule through the bright and dark states of the fluorescent screen;

[0011] Among them, the optical microstructure is a all-dielectric chiral metasurface device with polarization selectivity, which is used for polarization selection of the circularly polarized light transmitted by the chiral molecule, so that only one of the left-handed circularly polarized light or the right-handed circularly polarized light selected by polarization can be transmitted to the fluorescent screen on the other side of the all-dielectric chiral metasurface device;

[0012] The fluorescent screen is a screen coated with phosphor powder, which lights up when irradiated by light and is used to detect whether there is light transmitted out on the other side of the all-dielectric chiral metasurface device.

[0013] Further, when the optical microstructure is an all-dielectric chiral metasurface device with right-handed circular polarization selectivity, if the fluorescent screen is bright, the chiral molecule to be recognized is a right-handed chiral molecule, and if the fluorescent screen is dark, the chiral molecule to be recognized is a left-handed chiral molecule;

[0014] When the optical microstructure is an all-dielectric chiral metasurface device with left-handed circular polarization selectivity, if the fluorescent screen is bright, the chiral molecule to be recognized is a left-handed chiral molecule, and if the fluorescent screen is dark, the chiral molecule to be recognized is a right-handed chiral molecule.

[0015] Further, the all-dielectric chiral metasurface device includes a plurality of unit structures arranged periodically in the XOY plane, and each unit structure includes a silicon dioxide-based bottom layer and a silicon resonant layer stacked from bottom to top along the Z-axis, wherein the silicon resonant layer is located on the side close to the chiral molecule, and the silicon dioxide-based bottom layer is located on the side far from the chiral molecule;

[0016] The silicon resonant layer includes a first rectangular strip, a second rectangular strip, and a third rectangular strip that are integrally formed. Among them, the second rectangular strip extends along the Y-axis direction, and the first rectangular strip and the third rectangular strip extend along the X-axis direction; the first rectangular strip, the second rectangular strip, and the third rectangular strip are sequentially and perpendicularly connected end to end, and the first rectangular strip and the third rectangular strip are respectively located on opposite sides of the second rectangular strip in the X-axis direction, so that the projected shape of the silicon resonant layer on the XOY plane is Z-shaped or mirror Z-shaped.

[0017] Further, the second rectangular strip is disposed at the center of the upper surface of the silicon dioxide-based bottom layer. The positive Y-axis end of the second rectangular strip is perpendicularly connected to the positive X-axis end of the first rectangular strip, and the negative Y-axis end of the second rectangular strip is perpendicularly connected to the negative X-axis end of the third rectangular strip;

[0018] When performing chiral molecule recognition, if the fluorescent screen is bright, the chiral molecule to be recognized is a right-handed chiral molecule, and if the fluorescent screen is dark, the chiral molecule to be recognized is a left-handed chiral molecule.

[0019] Further, the second rectangular strip is disposed at the center of the upper surface of the silicon dioxide-based bottom layer. The positive Y-axis end of the second rectangular strip is perpendicularly connected to the negative X-axis end of the first rectangular strip, and the negative Y-axis end of the second rectangular strip is perpendicularly connected to the positive X-axis end of the third rectangular strip;

[0020] When performing chiral molecule recognition, if the fluorescent screen is bright, the chiral molecule to be recognized is a left-handed chiral molecule, and if the fluorescent screen is dark, the chiral molecule to be recognized is a right-handed chiral molecule.

[0021] Further, the lengths of the first rectangular strip and the third rectangular strip are both 112 nm, and the widths are both 41 nm; the length and width of the second rectangular strip are both 41 nm.

[0022] Further, in the all-dielectric chiral metasurface device, the thickness of the silicon dioxide-based bottom layer is 226 nm, and the thickness of the silicon resonant layer is 262 nm.

[0023] Further, the dielectric constant of the silicon resonant layer is 2.1025, and the dielectric constant of the silicon dioxide-based bottom layer is 11.9.

[0024] Further, the arrangement periods of the unit structure in the X-axis and Y-axis directions are both 430 nm.

[0025] The present invention adopts a method of combining an optical microstructure with a fluorescent screen. By utilizing the polarization selectivity of the optical microstructure for circularly polarized light, the weak chiral molecule recognition signal is amplified, and then the chiral molecule signal is recognized by observing the bright and dark states of the fluorescent screen. Compared with the traditional spectral analysis method, the method of the present invention converts the spectral signal into a visual signal image to recognize the chiral molecule configuration information, changes the discrimination basis of chiral molecules from the weak spectral signal difference to the presence or absence of transmitted light, and transforms from a quantitative recognition method to a qualitative recognition method. The chirality of biomolecules can be recognized through the bright and dark states of the fluorescent screen, which is particularly suitable for recognizing trace-doped chiral molecules. This method has the characteristics of simple operation, fast response speed, high recognition accuracy, and wide application range, and has extremely strong practicality. At the same time, according to actual needs, the polarization selectivity can be flexibly adjusted by changing the geometric structure parameters of the optical microstructure to adapt to various different application scenarios. Description of the Drawings

[0026] Figure 1 is a flowchart of a method for recognizing chiral molecules by spectral analysis in the prior art.

[0027] Figure 2 is a schematic flowchart of a method for amplifying a chiral molecule recognition signal by using an optical microstructure provided in Embodiment 1 of the present invention.

[0028] Figure 3 is an overall structural schematic diagram of the unit structure of a all-dielectric chiral metasurface device in Embodiment 1 of the present invention.

[0029] Figure 4 is a top view of the unit structure of a all-dielectric chiral metasurface device in Embodiment 1 of the present invention.

[0030] Figure 5 is a polarization transmission spectrum diagram of a all-dielectric chiral metasurface device in Embodiment 1 of the present invention.

[0031] Figure 6 is a schematic diagram of the electric field and magnetic field distributions of a all-dielectric chiral metasurface device in Embodiment 1 of the present invention when left-handed circularly polarized light and right-handed circularly polarized light are incident.

[0032] Figure 7 is a schematic flowchart of a method for amplifying a chiral molecule recognition signal by using an optical microstructure provided in Embodiment 2 of the present invention.

[0033] Figure 8 is a top view of the unit structure of a all-dielectric chiral metasurface device in Embodiment 2 of the present invention.

[0034] Figure 9 is a polarization transmission spectrum diagram of a all-dielectric chiral metasurface device in Embodiment 2 of the present invention.

[0035] Figure 10 It is a schematic diagram of the electric field and magnetic field distributions when the all-dielectric chiral metasurface device in the second embodiment of the present invention is irradiated by left-handed circularly polarized light and right-handed circularly polarized light.

[0036] Figure 11 It is a contrast diagram of the circular dichroism differences of the all-dielectric chiral metasurface devices in the first and second embodiments of the present invention. Detailed implementation manners

[0037] The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] According to the prior art, to distinguish whether a chiral molecule is a right-handed chiral molecule (D enantiomer) or a left-handed chiral molecule (L enantiomer), the traditional method is to analyze their transmission spectra; for example, when a linearly polarized light beam irradiates a chiral molecule, the chiral molecule will produce an optical effect on the linearly polarized light. The linearly polarized light passing through a left-handed chiral molecule will be converted into left-handed circularly polarized light, and similarly, the linearly polarized light passing through a right-handed chiral molecule will be converted into right-handed circularly polarized light. As Figure 1 shown, it is a method for identifying chiral molecules by spectral analysis in the prior art: after a linearly polarized light beam passes through a left-handed chiral molecule and a right-handed chiral molecule, due to different absorption coefficients, assuming that the left-handed chiral molecule and the right-handed chiral molecule respectively absorb 0.1 and 0.05 of the linearly polarized light, and after conversion, 0.9 and 0.95 of left-handed circularly polarized light and right-handed circularly polarized light are respectively transmitted. In this case, the difference in the transmitted light intensities of the left-handed chiral molecule and the right-handed chiral molecule is very small, only 0.05. For trace doping of chiral molecules, the intensity difference between the two is even weaker. Therefore, it is very difficult to capture this subtle difference through spectral analysis and then obtain whether the transmitted light is left-handed circularly polarized light or right-handed circularly polarized light; that is, it is very difficult to judge the configurational information of chiral molecules through spectral analysis. Therefore, for trace-doped chiral molecules, it is very important to amplify their recognition signals.

[0039] To solve the above problems, a method for amplifying the recognition signal of chiral molecules using an optical microstructure provided by the present invention includes:

[0040] Irradiate from one side in the Z-axis direction of the chiral molecule to be recognized with a linearly polarized light beam;

[0041] On the other side in the Z-axis direction of the chiral molecule to be recognized, an optical microstructure and a fluorescent screen are sequentially arranged; both the optical microstructure and the fluorescent screen are arranged perpendicular to the Z-axis;

[0042] Identify the configurational type of the chiral molecule through the bright and dark states of the fluorescent screen;

[0043] Among them, the optical microstructure is an all-dielectric chiral metasurface device with polarization selectivity, which is used to perform polarization selection on the circularly polarized light transmitted by chiral molecules, so that only one of the left-handed circularly polarized light or the right-handed circularly polarized light selected by polarization can be transmitted to the fluorescent screen on the other side of the all-dielectric chiral metasurface device;

[0044] The fluorescent screen is a screen coated with phosphor. When light irradiates the fluorescent screen, the fluorescent screen lights up, which is used to detect whether there is light transmitted out on the other side of the all-dielectric chiral metasurface device.

[0045] Specifically, when the optical microstructure is an all-dielectric chiral metasurface device with right-handed circular polarization selectivity, if the fluorescent screen is lit, the chiral molecule to be identified is a right-handed chiral molecule; if the fluorescent screen is dark, the chiral molecule to be identified is a left-handed chiral molecule;

[0046] When the optical microstructure is an all-dielectric chiral metasurface device with left-handed circular polarization selectivity, if the fluorescent screen is lit, the chiral molecule to be identified is a left-handed chiral molecule; if the fluorescent screen is dark, the chiral molecule to be identified is a right-handed chiral molecule.

[0047] Next, two embodiments will be combined to provide two all-dielectric chiral metasurface devices with different polarization selectivities to illustrate the working principle and working process of the present invention in detail. Embodiment 1

[0048] In this embodiment, the optical microstructure adopted is an all-dielectric chiral metasurface device with right-handed circular polarization selectivity.

[0049] Such as Figure 2As shown in the figure, it is a schematic flowchart of a method for amplifying chiral molecule recognition signals using an optical micro-structure provided in the first embodiment of the present invention. Its working principle and process are as follows: First, a linearly polarized light beam is used to irradiate from one side in the Z-axis direction of the chiral molecule to be recognized; the left-handed circularly polarized light or right-handed circularly polarized light transmitted through the chiral molecule is further irradiated onto the all-dielectric chiral metasurface device. The all-dielectric chiral metasurface device has different transmission characteristics for left-handed circularly polarized light and right-handed circularly polarized light; in this embodiment, the all-dielectric chiral metasurface device used has a transmittance of only 0.008 for left-handed circularly polarized light, so it mainly reflects left-handed circularly polarized light, while the transmittance for right-handed circularly polarized light is as high as 0.952, so it mainly transmits right-handed circularly polarized light; the transmission difference between left-handed circularly polarized light and right-handed circularly polarized light is 0.944, that is, most of the right-handed circularly polarized light can be transmitted through the metasurface. Based on the above principle, after the circularly polarized light transmitted from the chiral molecule passes through the all-dielectric chiral metasurface device, the right-handed circularly polarized light can be transmitted to the other side of the metasurface, while the left-handed circularly polarized light cannot reach the other side. Finally, the presence or absence of transmitted light on the other side of the all-dielectric chiral metasurface device can be judged by the bright and dark states of the fluorescent screen. If the fluorescent screen is in a bright state, it means that right-handed circularly polarized light is transmitted, and the chiral molecule to be recognized is a right-handed chiral molecule; if the fluorescent screen is in a dark state, it means that no right-handed circularly polarized light is transmitted, and the chiral molecule to be recognized is a left-handed chiral molecule.

[0050] Specifically, as Figure 3 and Figure 4 shown, the all-dielectric chiral metasurface device in this embodiment includes a plurality of unit structures arranged periodically in the XOY plane. Each unit structure includes a silica-based bottom layer 2 and a silicon resonant layer 1 stacked layer by layer from bottom to top along the Z axis. Among them, the silicon resonant layer 1 is located on the side close to the chiral molecule, and the silica-based bottom layer 2 is located on the side far from the chiral molecule (i.e., the side close to the fluorescent screen);

[0051] The silicon resonant layer 1 includes a first rectangular strip 31, a second rectangular strip 32, and a third rectangular strip 33 integrally formed. Among them, the second rectangular strip 32 extends along the Y axis direction, and the first rectangular strip 31 and the third rectangular strip 33 extend along the X axis direction; the first rectangular strip 31, the second rectangular strip 32, and the third rectangular strip 33 are sequentially connected end to end vertically, and the first rectangular strip 31 and the third rectangular strip 33 are respectively located on the opposite sides of the second rectangular strip 32 in the X axis direction, so that the projection shape of the silicon resonant layer 1 on the XOY plane is Z-shaped.

[0052] In this embodiment, the second rectangular strip 32 is disposed at the center of the upper surface of the silica-based substrate 2. The positive end of the Y-axis of the second rectangular strip 32 is perpendicularly connected to the positive end of the X-axis of the first rectangular strip 31, and the negative end of the Y-axis of the second rectangular strip 32 is perpendicularly connected to the negative end of the X-axis of the third rectangular strip 33.

[0053] The dimensional parameters of the unit structure are as follows: The lengths of the first rectangular strip 31 and the third rectangular strip 33 are both L1 = 112 nm, and the widths are both L2 = 41 nm; the length and width of the second rectangular strip 32 are both W = 41 nm. The arrangement periods of the unit structure in the X-axis and Y-axis directions are both P x = P y = 430 nm.

[0054] Furthermore, the thickness of the silica-based substrate 2 is 226 nm, and the thickness of the silicon resonant layer 1 is 262 nm. The dielectric constant of the silicon resonant layer 1 is 2.1025, and the dielectric constant of the silica-based substrate 2 is 11.9.

[0055] Based on the above structure, the all-dielectric chiral metasurface device in this embodiment realizes right-handed circular polarization selectivity. As Figure 5 and Figure 6 shown, it is the simulation result diagram of the all-dielectric chiral metasurface device in the first embodiment of the present invention. By using the frequency-domain finite element method simulated by the electromagnetic simulation software CST Studio Suite, the polarization transmission and transmission spectrum of the all-dielectric chiral metasurface device can be numerically calculated. When performing the simulation calculation, the unit cell periodic boundary condition is selected in the X-axis and Y-axis directions, and the open boundary condition is selected in the Z-axis direction. Among them, Figure 5 is the polarization transmission spectrum diagram, and TL and TR are the transmission spectra of left-handed circularly polarized light incident and right-handed circularly polarized light incident respectively. It can be seen from Figure 5 that in the visible light band, when the wavelength is 466.84 nm, the transmittance TL of the left-handed circularly polarized light is 0.008, and the transmittance TR of the right-handed circularly polarized light is 0.952, that is, the left-handed circularly polarized light is nearly completely reflected after incident on the all-dielectric chiral metasurface device, while the right-handed circularly polarized light is nearly completely transmitted.

[0056] Figure 6 in (a) and Figure 6 in (b) are respectively the electric field distribution diagrams of the all-dielectric chiral metasurface device in this embodiment under the incidence of left-handed and right-handed circularly polarized light. By comparison, it can be seen that the electric field distributions of the metasurface under the incidence of left-handed and right-handed circularly polarized light are similar, the electric field modes are the same, and the electric field intensity under the incidence of right-handed circularly polarized light is stronger than that under the incidence of left-handed circularly polarized light. Figure 6 in (c) and Figure 6(d) in this embodiment are the magnetic field distribution diagrams of the all-dielectric chiral metasurface device under the incidence of left-handed and right-handed circularly polarized light, respectively. It can be seen that the magnetic field intensity under the incidence of left-handed circularly polarized light is stronger than that under the incidence of right-handed circularly polarized light. The difference in the electric and magnetic field intensities also causes the difference in their transmissions, resulting in strong circular dichroism. Embodiment 2

[0057] In this embodiment, the optical microstructure adopted is an all-dielectric chiral metasurface device with left-handed circular polarization selectivity.

[0058] As Figure 7 shown, it is a schematic flowchart of a method for amplifying chiral molecule recognition signals using an optical microstructure provided in Embodiment 2 of the present invention. Its working principle and working process are generally similar to those in Embodiment 1, except that the all-dielectric chiral metasurface device adopted in this embodiment is the structure after mirroring of Embodiment 1, which in turn leads to different polarization selectivities for circularly polarized light.

[0059] Specifically, the all-dielectric chiral metasurface device in this embodiment has a transmission effect on left-handed circularly polarized light and a reflection effect on right-handed circularly polarized light, that is, the left-handed circularly polarized light is almost completely transmitted and can reach the other side of the metasurface; while the right-handed circularly polarized light is almost completely reflected and cannot reach the other side of the metasurface, and the transmission difference between the left-handed circularly polarized light and the right-handed circularly polarized light is relatively large. Based on the above characteristics, when performing chiral molecule recognition, if the fluorescent screen is in a bright state, it indicates that there is left-handed circularly polarized light transmitted, and the chiral molecule to be recognized is a left-handed chiral molecule; if the fluorescent screen is in a dark state, it indicates that there is no left-handed circularly polarized light transmitted, and the chiral molecule to be recognized is a right-handed chiral molecule.

[0060] As Figure 8 shown, the all-dielectric chiral metasurface device in this embodiment is basically the same as the all-dielectric chiral metasurface device in Embodiment 1, except that the shape of the silicon resonance layer 1 is mirror-symmetric with that in Embodiment 1. Specifically, in this embodiment, the second rectangular strip 32 is disposed at the center of the upper surface of the silicon dioxide base layer 2, the positive Y-axis end of the second rectangular strip 32 is vertically connected to the negative X-axis end of the first rectangular strip 31, and the negative Y-axis end of the second rectangular strip 32 is vertically connected to the positive X-axis end of the third rectangular strip 33, so that the projection shape of the silicon resonance layer 1 on the XOY plane is a mirror Z shape.

[0061] The size parameters of the all-dielectric chiral metasurface device in this embodiment are also the same as those provided in Embodiment 1: the lengths of the first rectangular strip 31 and the third rectangular strip 33 are both L1 = 112 nm, and the widths are both L2 = 41 nm; the length and width of the second rectangular strip 32 are both W = 41 nm. The arrangement periods of the unit structure in the X-axis and Y-axis directions are both P x=P y = 430 nm.

[0062] Furthermore, the thickness of the silica-based bottom layer 2 is 226 nm, and the thickness of the silicon resonant layer 1 is 262 nm. The dielectric constant of the silicon resonant layer 1 is 2.1025, and the dielectric constant of the silica-based bottom layer 2 is 11.9.

[0063] Based on the above structure, the all-dielectric chiral metasurface device in this embodiment realizes left-handed circular polarization selectivity. As Figure 9 and Figure 10 shown, it is the simulation result diagram of the all-dielectric chiral metasurface device in the second embodiment of the present invention. The simulation method and simulation conditions are both the same as those provided in the first embodiment. Among them, Figure 9 is the polarization transmission spectrum diagram. TL and TR are the transmission spectra of left-handed circularly polarized light incident and right-handed circularly polarized light incident respectively. Through Figure 9 it can be seen that in the visible light band, when the wavelength is 466.84 nm, the transmittance TL of the left-handed circularly polarized light is 0.956, and the transmittance TR of the right-handed circularly polarized light is 0.003, that is, the left-handed circularly polarized light is almost completely transmitted after entering the all-dielectric chiral metasurface device, while the right-handed circularly polarized light is almost completely reflected.

[0064] Figure 10 In (a) of Figure 10 and (b) of Figure 10 are the electric field distribution diagrams of the all-dielectric chiral metasurface device in this embodiment under the incidence of left-handed and right-handed circularly polarized light respectively. By comparison, it can be seen that the electric field distributions of the metasurface under the incidence of left-handed and right-handed circularly polarized light are similar, the electric field patterns are the same, and the electric field intensity under the incidence of left-handed circularly polarized light is stronger than that under the incidence of right-handed circularly polarized light. Figure 10 In (c) of

[0065] Figure 11 and (d) of Z are the magnetic field distribution diagrams of the all-dielectric chiral metasurface device in this embodiment under the incidence of left-handed and right-handed circularly polarized light respectively. It can be seen that the magnetic field intensity under the incidence of right-handed circularly polarized light is stronger than that under the incidence of left-handed circularly polarized light. Combining the differences in electric and magnetic field intensities, it causes the differences in their transmissions and generates strong circular dichroism. Z is the circular dichroism of the Z-shaped all-dielectric chiral metasurface device described in the first embodiment of the present invention. CDmirror-z is the circular dichroism of the mirror Z-shaped all-dielectric chiral metasurface device described in the second embodiment, CD mirror-z = +0.953, achieving polarization selection for left-handed circularly polarized light. It can be seen from the circular dichroism difference comparison diagram that strong circular dichroism can be achieved in both the first and second embodiments in the visible light band.

[0066] Compared with the prior art, the present invention has the following advantages:

[0067] 1. Traditional spectral analysis methods are difficult to identify chiral molecules with trace doping because their left-handed and right-handed signals are weak and have a small difference. By using an all-dielectric chiral metasurface device, the present invention can greatly change the difference between the left-handed and right-handed signals from 0 to 1 in the visible light band, realizing the amplification of the identification signal of chiral molecules with trace doping.

[0068] 2. Utilizing the polarization selectivity of the all-dielectric chiral metasurface device to amplify the optical effect, converting spectral signals with small differences into visual signal images, and directly identifying the chiral type of chiral molecules through the bright and dark states of the fluorescent screen, without the need to analyze the intensities of left-handed circularly polarized light and right-handed circularly polarized light as in traditional spectral analysis methods to identify the chiral type of chiral molecules. This method can intuitively and quickly determine the configuration information of chiral molecules.

[0069] 3. The optical microstructure adopted in the present invention, namely the all-dielectric chiral metasurface device, has different local field enhancement effects on left-handed circularly polarized light and right-handed circularly polarized light in the visible light band, resulting in different transmittances for left-handed circularly polarized light and right-handed circularly polarized light, achieving strong circular dichroism.

[0070] In summary, the present invention adopts a method combining an optical microstructure and a fluorescent screen. By using the polarization selectivity of the optical microstructure to amplify the weak chiral molecule identification signal, and then identifying the chiral molecule signal by observing the bright and dark states of the fluorescent screen. Compared with traditional spectral analysis methods, the method of the present invention converts spectral signals into visual signal images to identify the configuration information of chiral molecules, which is particularly suitable for identifying chiral molecules with trace doping. This method has the characteristics of simple operation, fast response speed, high identification accuracy, and wide application range, and has extremely strong practicability. At the same time, according to actual needs, the polarization selectivity can be flexibly adjusted by changing the geometric structure parameters of the optical microstructure to adapt to various different application scenarios.

[0071] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several variations and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention shall be subject to the appended claims.

Claims

1. A method for amplifying the chiral molecular recognition signal by using an optical microstructure, characterized in that, Comprising: Irradiate from one side in the Z-axis direction of the chiral molecule to be identified with a beam of linearly polarized light; On the other side in the Z-axis direction of the chiral molecule to be identified, an optical microstructure and a fluorescent screen are sequentially arranged; both the optical microstructure and the fluorescent screen are arranged perpendicular to the Z-axis; Identify the configuration type of the chiral molecule through the bright and dark states of the fluorescent screen; Wherein, the optical microstructure is a all-dielectric chiral metasurface device with polarization selectivity, which is used to perform polarization selection on the circularly polarized light transmitted by the chiral molecule, so that only one of the left-handed circularly polarized light or the right-handed circularly polarized light selected by polarization can be transmitted to the fluorescent screen on the other side of the all-dielectric chiral metasurface device; The fluorescent screen is a screen coated with phosphor, and when light irradiates on the fluorescent screen, the fluorescent screen lights up, which is used to detect whether there is light transmitted out on the other side of the all-dielectric chiral metasurface device; The all-dielectric chiral metasurface device includes a plurality of unit structures arranged periodically in the XOY plane, and each unit structure respectively includes a silica-based bottom layer and a silicon resonant layer stacked from bottom to top along the Z-axis, wherein the silicon resonant layer is located on the side close to the chiral molecule, and the silica-based bottom layer is located on the side far from the chiral molecule; The silicon resonant layer includes a first rectangular strip, a second rectangular strip and a third rectangular strip integrally formed, wherein the second rectangular strip extends along the Y-axis direction, and the first rectangular strip and the third rectangular strip extend along the X-axis direction; the first rectangular strip, the second rectangular strip and the third rectangular strip are sequentially connected end to end vertically, and the first rectangular strip and the third rectangular strip are respectively located on the opposite sides of the second rectangular strip in the X-axis direction, so that the projected shape of the silicon resonant layer in the XOY plane is Z-shaped or mirror Z-shaped; When the optical microstructure is an all-dielectric chiral metasurface device with right-handed circular polarization selectivity, the second rectangular strip is arranged at the center of the upper surface of the silica-based bottom layer, the positive end of the Y-axis of the second rectangular strip is vertically connected to the positive end of the X-axis of the first rectangular strip, and the negative end of the Y-axis of the second rectangular strip is vertically connected to the negative end of the X-axis of the third rectangular strip; when identifying the chiral molecule, if the fluorescent screen is bright, the chiral molecule to be identified is a right-handed chiral molecule, and if the fluorescent screen is dark, the chiral molecule to be identified is a left-handed chiral molecule; When the optical microstructure is an all-dielectric chiral metasurface device with left-handed circular polarization selectivity, the second rectangular strip is arranged at the center of the upper surface of the silica-based bottom layer, the positive end of the Y-axis of the second rectangular strip is vertically connected to the negative end of the X-axis of the first rectangular strip, and the negative end of the Y-axis of the second rectangular strip is vertically connected to the positive end of the X-axis of the third rectangular strip; when identifying the chiral molecule, if the fluorescent screen is bright, the chiral molecule to be identified is a left-handed chiral molecule, and if the fluorescent screen is dark, the chiral molecule to be identified is a right-handed chiral molecule; The lengths of the first rectangular strip and the third rectangular strip are both 112 nm, and the widths are both 41 nm; the length and width of the second rectangular strip are both 41 nm; In the all-dielectric chiral metasurface device, the thickness of the silica-based bottom layer is 226 nm, and the thickness of the silicon resonant layer is 262 nm; The arrangement period of the unit structure on both the X-axis and the Y-axis is 430 nm; The all-dielectric chiral metasurface device operates in the visible light band of 460 - 470 nm.

Images