An electrically controlled chiral display device and its application

Abstract

The present invention relates to an electrically controlled chiral display device and its application, comprising a substrate, a plurality of control units with the same structure, a top electrode and a bottom electrode; the plurality of control units are periodically arranged on the substrate, and the top electrode and the bottom electrode are respectively arranged on both sides of the plurality of control units; each control unit comprises a metal reflective layer, a bottom metal rod, a dielectric layer and a top metal rod; since the top metal rod and the bottom metal rod of the present invention form an asymmetric chiral structure in space, the present invention generates a larger CD signal, and changes the refractive index of the bottom metal rod and the entire dielectric layer by applying an external voltage, so that the plasmon effect between the top metal rod and the bottom metal rod of the structure changes, thereby changing the peak value and peak position of the CD signal, thereby realizing electrical control of the CD signal, i.e., the chiral signal, and the control amplitude is sufficient to be recognized by an optical detector, and can be used for chiral display, sensing, etc.

Description

Technical Field

[0001] The invention relates to an electrically controlled chiral display device and application thereof, belonging to the technical field of chirality regulation. Background Art

[0002] The word chirality comes from Greek, which means the symmetry of a structure. If an object cannot overlap with its mirror image through translation, it is called "chiral", just like our left hand and right hand are mirror images of each other and cannot overlap. Chirality is widely present in nature. Living things such as DNA and proteins have chirality. Chiral structures show different electromagnetic responses to the absorption and transmittance of left-circularly polarized light (LCP) and right-circularly polarized light (RCP). This different electromagnetic response is usually characterized by circular dichroism (CD). The definition formula of CD is CD=A LCP -A RCP The coupling between circularly polarized light and the chiral structure in nature is very weak, which makes it difficult for natural chiral molecules to effectively modulate electromagnetic waves.

[0003] In order to solve the problem of very weak coupling between natural chiral structures and electromagnetic waves, an optical structure composed of metasurface materials has emerged in recent years to regulate electromagnetic responses. This metasurface material is a planar optical and electromagnetic wave regulation material composed of subwavelength-scale nanostructures. At present, metasurface materials have attracted the attention of more and more researchers due to their unique advantages in the field of electromagnetic waves. Plasmonic metasurfaces, which are composed of metal nanostructures as basic units, not only show the light field regulation characteristics of the metasurface when interacting with light, but also enhance the interaction between the material and light due to the surface plasmon enhancement effect of the metal structure. Based on this,

[0004] Artificial Plasmonic Chiral Nanostructures (APCNs) were proposed, which exhibit high CD effects that natural chiral molecules cannot achieve and are widely used in the fields of biological detection and sensing.

[0005] For example, in 2018, Shengxiang Wang et al. proposed to use twisted fishing net chiral metasurface to realize CD signal, and realized the regulation of CD signal by adjusting temperature. However, compared with planar APCNs, three-dimensional APCNs have added a dimension, and their ability to regulate CD signals is stronger. For example, in 2020, Guoli He et al. proposed that the three-dimensional cross-rod chiral structure achieved a high CD effect in the terahertz band, and realized the selective absorption of LCP or RCP by changing the device structure, and in theory realized the dynamic regulation of CD signal by ion implantation or applied voltage. In 2021, Jitao Li et al. designed a three-dimensional chiral structure composed of open gold rings and gold nanodisks, and realized different absorption of LCP or RCP by changing the direction and size of the gold ring opening, and dynamically regulated the CD signal by applying voltage to change the electron concentration of the bottom graphene. These research results have laid a solid theoretical and experimental foundation for the dynamic regulation of CD signals.

[0006] However, on the one hand, the device structure for regulating circular dichroism signals is relatively complex and requires wet etching and chemical implantation processes. On the other hand, the device structure has high material requirements, requires the participation of two-dimensional materials, and has a large number of layers, which requires high process precision. Summary of the invention

[0007] In view of the shortcomings of the device structure in the prior art, such as complex structure and high process requirements, the present invention proposes a nano device for electrically regulating chiral effect and its application, which is used for chiral display, sensing and other applications: on the one hand, it solves the problem that the device structure in the prior art is complex and requires wet etching, chemical injection, etc. to realize dynamic regulation of CD signals; on the other hand, it solves the problem that the device structure has high material requirements, requires the participation of two-dimensional materials, has a large number of layers, and requires high process precision. The present invention can realize the regulation of circular dichroism signals by applying voltage.

[0008] The technical solution of the present invention is:

[0009] A nano device for electrically regulating chiral effect, comprising a substrate, a plurality of regulating units with the same structure, a top electrode and a bottom electrode; the plurality of regulating units are periodically arranged on the substrate, and the top electrode and the bottom electrode are respectively arranged on both sides of the plurality of regulating units;

[0010] Each control unit includes a metal reflective layer, a bottom metal rod, a dielectric layer and a top metal rod; the metal reflective layer is arranged on the substrate, the dielectric layer is arranged on the metal reflective layer, the bottom metal rod is arranged in the dielectric layer and close to the metal reflective layer, the top metal rod is arranged on the dielectric layer, the metal reflective layer is connected to the bottom electrode, and the top metal rod is connected to the top electrode; the top metal rod and the bottom metal rod form an asymmetric chiral metal nanostructure in space;

[0011] The dielectric layer is a material that can conduct hydrogen protons.

[0012] Preferably according to the present invention, the dielectric layer is gadolinium oxide, tungsten trioxide or perovskite-type oxide.

[0013] Preferably according to the present invention, the refractive index of the dielectric layer is 1.6-1.8;

[0014] Further preferably, the refractive index of the dielectric layer is 1.7.

[0015] According to a preferred embodiment of the present invention, the bottom metal rod is made of a material that can be hydrogenated;

[0016] Further preferably, the material of the bottom metal rod is palladium Pd, magnesium Mg, platinum Pt, yttrium Y or graphite.

[0017] Preferably according to the present invention, the metal reflective layer, the top metal rod, the top electrode and the bottom electrode are all made of gold Au material.

[0018] Preferably, according to the present invention, the bottom metal rod is arranged in the dielectric layer directly below the top metal rod. The bottom metal rod is rotated 45 degrees counterclockwise with the Z axis as the central axis to form spatial asymmetry with the top metal rod, and its structural shape is a cross-rod structure.

[0019] Preferably according to the present invention, the thickness of the metal reflective layer is 30-200 nm;

[0020] The thickness of the dielectric layer is 140-160nm;

[0021] The width of the top metal rod and the bottom metal rod are both 90-110 nm, the height of the top metal rod and the bottom metal rod are both 20-40 nm, the length of the bottom metal rod is 260-340 nm, and the length of the top metal rod is 350-450 nm;

[0022] The period of the control unit is 350-450nm, which is equal to the length of the top metal rod;

[0023] The distance between the lower surface of the bottom metal rod and the upper surface of the metal reflective layer is 10-30 nm, and the distance between the upper surface of the bottom metal rod and the upper surface of the dielectric layer is 110-90 nm;

[0024] The distance between the lower surface of the top metal rod and the upper surface of the bottom metal rod is 110-90 nm, and the angle between the horizontal planes of the top metal rod and the bottom metal rod is 0-90°.

[0025] Further preferably, the thickness of the metal reflective layer is 100 nm;

[0026] The thickness of the dielectric layer is 150nm;

[0027] The width of the top metal rod and the bottom metal rod are both 100 nm, the height of the top metal rod and the bottom metal rod are both 30 nm, the length of the bottom metal rod is 300 nm, and the length of the top metal rod is 400 nm;

[0028] The period of the control unit is 400nm, which is equal to the length of the top metal rod;

[0029] The distance between the lower surface of the bottom metal rod and the upper surface of the metal reflective layer is 20 nm, and the distance between the upper surface of the bottom metal rod and the upper surface of the dielectric layer is 100 nm;

[0030] The distance between the lower surface of the top metal rod and the upper surface of the bottom metal rod is 100 nm, and the angle between the horizontal planes of the top metal rod and the bottom metal rod is 45°.

[0031] The application of the above-mentioned nanodevice for electrically controlling chiral effect is used to realize the electrical control of CD signals, including:

[0032] The bottom electrode is externally connected to a negative power source, and the top electrode is externally connected to a positive power source;

[0033] When the external voltage is 0V or disconnected, a CD signal is generated;

[0034] When the external voltage is 3V-6V, the top metal rod material and the dielectric layer catalyze the decomposition of water molecules in the air to produce H protons and oxygen under the action of voltage. Under the action of the electric field, the H protons move from the top of the dielectric layer to the bottom, and encounter the bottom metal rod material during the movement. The H protons hydrogenate the bottom metal rod and change the refractive index of the bottom metal rod. At the same time, the hydrogen protons in the gadolinium oxide body also cause the refractive index of gadolinium oxide to change from 1.7 to 2.1, thereby changing the plasmon effect between the top metal rod and the bottom metal rod, thereby changing the original CD signal and realizing electrical regulation of the CD signal.

[0035] The beneficial effects of the present invention are:

[0036] The top metal rod and the bottom metal rod of the present invention form an asymmetric chiral structure in space, so the present invention will generate a larger CD signal, and by applying an external voltage, the refractive index of the bottom metal rod is changed, so that the plasmon effect between the top metal rod and the bottom metal rod of the structure is changed, thereby changing the peak value and peak position of the CD signal, thereby realizing electrical regulation of the CD signal, i.e., the chiral signal. The method is simple, the operation is controllable, and the cost is low. The regulation amplitude is sufficient to be recognized by an optical detector, and can be used for chiral display, sensing, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A three-dimensional schematic diagram of a chiral nanostructure with electrically tunable circular dichroism provided by an embodiment of the present invention;

[0038] Figure 2 A top view of a chiral nanostructure with electrically tunable circular dichroism provided by an embodiment of the present invention;

[0039] Figure 3 A three-dimensional stereogram of a control unit of a chiral nanostructure with electrically controllable circular dichroism provided by an embodiment of the present invention;

[0040] Figure 4 A front view of a control unit of a chiral nanostructure with electrically controllable circular dichroism provided by an embodiment of the present invention;

[0041] Figure 5 An absorption spectrum of a chiral nanostructure with electrically adjustable circular dichroism before voltage is applied and its circular dichroism CD spectrum provided by an embodiment of the present invention;

[0042] Figure 6 An absorption spectrum diagram and a circular dichroism CD spectrum diagram of a chiral nanostructure with electrically adjustable circular dichroism after voltage is applied provided by an embodiment of the present invention;

[0043] Figure 7 A CD spectrum of a chiral nanostructure with electrically adjustable circular dichroism provided by an embodiment of the present invention when a voltage of 0 V and a voltage of 6 V are applied twice;

[0044] Among them, 1. bottom electrode; 2. metal reflective layer; 3. dielectric layer; 4. bottom metal rod; 5. top metal rod; 6. top electrode; 7. substrate. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0046] Example 1

[0047] A nanodevice for electrically controlling chiral effects, such as Figure 1 , Figure 2 As shown, it includes a substrate 7, a plurality of control units with the same structure, a top electrode 6 and a bottom electrode 1; the plurality of control units are periodically arranged on the substrate 7, and the top electrode 6 and the bottom electrode 1 are respectively arranged on both sides of the plurality of control units;

[0048] like Figure 3 , Figure 4As shown, each control unit includes a metal reflective layer 2, a bottom metal rod 4, a dielectric layer 3 and a top metal rod 5; the metal reflective layer 2 is arranged on a substrate 7, the dielectric layer 3 is arranged on the metal reflective layer 2, the bottom metal rod 4 is arranged in the dielectric layer 3 and close to the metal reflective layer 2, the top metal rod 5 is arranged on the dielectric layer 3, the metal reflective layer 2 is connected to a bottom electrode 1, and the top metal rod 5 is connected to a top electrode 6; the top metal rod 5 and the bottom metal rod 4 form an asymmetric chiral metal nanostructure in space;

[0049] The dielectric layer 3 is a material that can conduct hydrogen protons.

[0050] Since the top metal rod 5 and the bottom metal rod 4 of the present invention form an asymmetric chiral structure in space, the present invention will generate a larger CD signal, and by applying an external voltage, the refractive index of the bottom metal rod 4 and the dielectric layer 3 is changed, so that the plasmon effect between the top metal rod 5 and the bottom metal rod 4 of the structure is changed, thereby changing the peak value and peak position of the CD signal, thereby realizing electrical regulation of the CD signal, i.e., the chiral signal, and the regulation amplitude is sufficient to be recognized by an optical detector, and can be used for chiral display, sensing, etc.

[0051] Example 2

[0052] The difference of the nanodevice for electrically controlling chiral effect according to embodiment 1 is that:

[0053] The dielectric layer 3 is tungsten trioxide or perovskite oxide.

[0054] Example 3

[0055] The difference of the nanodevice for electrically controlling chiral effect according to embodiment 1 is that:

[0056] The bottom metal rod 4 is made of a hydrogenatable material; the material of the bottom metal rod 4 is palladium Pd, magnesium Mg, platinum Pt, yttrium Y or graphite. The substrate 7 can be a common substrate 7 of silicon dioxide, silicon, aluminum oxide and the like;

[0057] Palladium Pd can absorb a large amount of hydrogen H at room temperature and pressure to form PdH x , changing its optical parameter refractive index. Similar hydrogen storage materials include platinum Pt, magnesium Mg, yttrium Y and graphite. Since Pd has a lower activation barrier for hydrogen protons, a fast hydrogen storage speed and low requirements for hydrogen storage conditions, palladium Pd is selected as the material of the bottom metal rod 4 in this embodiment; gadolinium oxide GdO x It is a material that can conduct H protons. When a layer of Au film is grown on its surface, Au and gadolinium oxide GdO x The surface will catalyze water molecules in the air to produce H protons, which will be driven by voltage and will be xIn this embodiment, the Pd as the bottom metal rod 4 will be hydrogenated into PdH by the H protons inside the gadolinium oxide of the dielectric layer 3. x , thereby changing its refractive index. At the same time, due to the injection of hydrogen protons, gadolinium oxide GdO x The refractive index will change from the original 1.7 to 2.1. Therefore, the plasmon effect formed by the top metal rod 5 and the bottom metal rod 4 will change, thereby realizing the electrical control of the CD signal.

[0058] The thickness h of the metal reflective layer 2 is 30-200 nm; the thickness h of the dielectric layer 3 is 140-160 nm; the width w of the top metal rod 5 and the bottom metal rod 4 are both 90-110 nm, the height h of the top metal rod 5 and the bottom metal rod 4 are both 20-40 nm, and the length L of the bottom metal rod 4 is 1 is 260-340nm, and the length L of the top metal rod 5 2 is 350-450nm; the period P of the control unit is 350-450nm, which is equal to the length of the top metal rod 5; the distance t between the lower surface of the bottom metal rod 4 and the upper surface of the metal reflective layer 2 is 10-30nm, and the distance d between the upper surface of the bottom metal rod 4 and the upper surface of the dielectric layer 3 is 110-90nm; the distance d between the lower surface of the top metal rod 5 and the upper surface of the bottom metal rod 4 is 110-90nm, and the horizontal plane angle between the top metal rod 5 and the bottom metal rod 4 is 0-90°.

[0059] Example 4

[0060] The difference of the nanodevice for electrically controlling chiral effect according to embodiment 1 is that:

[0061] The medium layer 3 is gadolinium oxide; gadolinium oxide is preferably used as the hydrogen proton conducting medium layer because of its characteristics of simple preparation, high stability, and not easily affected by the ambient temperature.

[0062] The refractive index of the dielectric layer 3 is 1.7; the material that can conduct hydrogen protons is gadolinium oxide. For gadolinium oxide, in the visible light band, its refractive index changes in the range of about 1.6-1.8 in the uncharged state, and changes in the range of about 2.0-2.1 after charging with hydrogen.

[0063] The metal reflective layer 2, the top metal rod 5, the top electrode 6 and the bottom electrode 1 are all made of Au material. The bottom metal rod 4 is made of palladium Pd material that can be hydrogenated; the substrate 7 is a 300nm thick thermally oxidized SiO 2 Si substrate.

[0064] The bottom metal rod 4 is arranged in the dielectric layer 3 directly below the top metal rod 5. The bottom metal rod 4 is rotated 45° counterclockwise relative to the z-axis to form a spatial asymmetry with the top metal rod 5. The top view of the structure is approximately as follows: The bottom metal rod 4 and the top metal rod 5 are distributed in different planes parallel to the XY plane, and the bottom metal rod 4 is rotated 45 degrees counterclockwise with the Z axis as the central axis.

[0065] The horizontal angle between the bottom metal rod 4 and the top metal rod 5 in the present invention is a key factor affecting the present invention. By analyzing the Jones matrix method, it is concluded that the circularly polarized dichroic reflector cannot have a mirror symmetry property, and one of the most basic properties of the chiral structure is that it does not have a mirror symmetry. Therefore, to achieve a nearly perfect absorption of right-handed circularly polarized light, it is necessary to destroy its mirror symmetry. The destruction of the mirror symmetry is achieved by the relative rotation angle of the two metal rods. In the present invention, the torsion angle of the designed structure is 45°, and the CD signal response is optimal when the twist angle is 45°.

[0066] After selecting the constituent materials and shapes of the chiral nanostructures, the present invention can optimize the device structure size for achieving the best modulation effect in the visible-near infrared band (wavelength: 350nm-1200nm) through optical simulation methods such as finite-difference time-domain (FDTD) algorithm. The obtained optimal structural parameters are as follows:

[0067] The thickness h of the metal reflective layer 2 is 100 nm, the thickness h of the dielectric layer 3 is 150 nm, the width w of the top metal rod 5 and the bottom metal rod 4 are both 100 nm, the height h of the top metal rod 5 and the bottom metal rod 4 are both 30 nm, and the length L of the bottom metal rod 4 is 1 is 300 nm, and the length L of the top metal rod 5 is 2 is 400nm; the period P of the control unit is 400nm, which is equal to the length of the top metal rod 5; the distance t between the lower surface of the bottom metal rod 4 and the upper surface of the metal reflective layer 2 is 20nm, and the distance d between the upper surface of the bottom metal rod 4 and the upper surface of the dielectric layer 3 is 100nm; the distance d between the lower surface of the top metal rod 5 and the upper surface of the bottom metal rod 4 is 100nm, the horizontal plane angle between the top metal rod 5 and the bottom metal rod 4 is 45°, and the period p of the control unit is 400nm.

[0068] The method for preparing the above-mentioned nanodevice for electrically regulating chiral effect comprises the following specific steps:

[0069] Step 1: clean the substrate 7 and place a 300nm thick thermally oxidized SiO 2The Si substrate (1cm*1cm) was placed in Decon cleaning solution (Decon original solution and deionized water were diluted at 1:6), and the container was ultrasonically cleaned for 5 minutes, then rinsed with deionized water and dried with nitrogen; the substrate 7 was placed in deionized water for ultrasonic cleaning for 5 minutes, then rinsed with deionized water and dried with nitrogen; the substrate 7 was placed in an isopropanol solution for ultrasonic cleaning for 5 minutes, then placed in an ethanol solution for ultrasonic cleaning for 5 minutes, and then dried with nitrogen;

[0070] Step 2, evenly spin-coating 5350 photoresist on the substrate 7, and performing pattern exposure on the substrate 7 using an ultraviolet photolithography machine;

[0071] Step 3, placing the patterned substrate 7 into an electron beam evaporation coating machine to evaporate Au, the material of the metal reflective layer 2;

[0072] Step 4, evaporating a dielectric layer 3 material gadolinium oxide with a certain thickness on the metal reflective layer 2;

[0073] Step 5, evenly spin-coat PMMA electron beam glue on the device, and perform pattern exposure using an electron beam exposure process, the pattern being the bottom metal rod 4 pattern;

[0074] Step 6, placing the device with the bottom metal rod 4 pattern into an electron beam evaporation coating machine to evaporate the bottom metal rod 4 material Pd;

[0075] Step 7, evenly spin-coat 5350 photoresist on the device, and use a UV photolithography machine to perform pattern exposure on the device;

[0076] Step eight, evaporating a certain thickness of dielectric layer 3 material gadolinium oxide on the device with patterns;

[0077] Step nine, evenly spin-coat PMMA electron beam glue on the device, and perform pattern exposure using an electron beam exposure process, the pattern being the top metal rod 5 pattern;

[0078] Step 10, placing the device with the top metal rod 5 pattern into an electron beam evaporation coating machine to evaporate the top metal rod 5 material Au;

[0079] In the above step 1, the ultrasonic power is 90w;

[0080] In the above steps 2 and 7, before and after spin coating 5350 photoresist, the device needs to be baked for 3 minutes at a baking temperature of 110°C, and after exposure by the UV lithography machine, the pattern needs to be developed with 5350 developer;

[0081] In the above step 3, no operation is required before proceeding to step 4, and step 4 can be directly performed;

[0082] After the corresponding materials are deposited in the above steps 4, 6, 8 and 10, the adhesive is removed by using an acetone solution. The device is placed in the acetone solution for 15 minutes and then blown dry with a nitrogen gun.

[0083] In the above steps 5 and 9, before and after spin coating of PMMA glue, the device needs to be baked for 10 minutes at a baking temperature of 150° C., and after electron beam exposure, the pattern needs to be developed with PMMA developer.

[0084] Since the top metal rod 5 and the bottom metal rod 4 form an asymmetric chiral structure, they can strongly absorb RCP (LCP) and suppress LCP (RCP) absorption, thereby generating a larger CD signal; in this embodiment, since the bottom metal rod 4 rotates 45° counterclockwise with the z-axis as the rotation axis, the top metal rod 5 and the bottom metal rod 4 form a right-handed structure in three-dimensional space. Therefore, the chiral structure shown in this embodiment has a peak absorption rate of 0.92 for RCP and a peak absorption rate of 0.58 for LCP, so the generated CD (CD = A LCP -A RCP ) signal peak is -0.56; palladium Pd can absorb a large amount of hydrogen H at room temperature and pressure to form PdH x , changing its optical parameter refractive index. Similar hydrogen storage materials include platinum Pt, magnesium Mg, yttrium Y and graphite. Since Pd has a lower activation barrier for hydrogen protons, a fast hydrogen storage speed, and low requirements for hydrogen storage conditions, Pd is selected as the material of the bottom metal rod 4 in this embodiment; gadolinium oxide GdO x It is a material that can conduct H protons. When a layer of Au film is grown on its surface, Au and gadolinium oxide GdO x The surface will catalyze water molecules in the air to produce H protons, which will be driven by voltage and will be x In this embodiment, the Pd as the bottom metal rod 4 will be hydrogenated into PdH by the H protons inside the gadolinium oxide of the dielectric layer 3. x , thereby changing its refractive index. At the same time, the injection of H protons into the gadolinium oxide in the dielectric layer 3 will also change its refractive index from 1.7 to 2.1, so the plasmon effect formed by the top metal rod 5 and the bottom metal rod 4 will change. The peak position of the CD signal is red-shifted from the original 958nm to 1247nm, and the peak value is reduced from the original 0.56 to 0.46, thereby realizing the electrical regulation of the CD signal.

[0085] Example 5

[0086] The application of the nanodevice for electrically controlling chiral effect described in any one of Examples 1 to 4 is used to realize the electrical control of CD signals, including:

[0087] The bottom electrode 1 is connected to the negative pole of an external power source, and the top electrode 6 is connected to the positive pole of an external power source;

[0088] When the external voltage is 0V or disconnected, since the top metal rod 5 and the bottom metal rod 4 form an asymmetric right-handed structure, strong absorption is generated on the RCP, which inhibits the LCP absorption, thereby generating a CD signal in the range of 0.38-0.56;

[0089] When the external voltage is 3V-6V, the Au material of the top metal rod 5 and the gadolinium oxide of the dielectric layer 3 catalyze the decomposition of water molecules in the air to produce H protons and oxygen under the action of voltage. The H protons move from the top of the dielectric layer 3 to the bottom thereof under the action of the electric field, and encounter the bottom metal rod 4 material during the movement of the H protons. The H protons hydrogenate the bottom metal rod 4, changing the refractive index of the bottom metal rod 4. At the same time, the hydrogen protons in the gadolinium oxide body also cause the refractive index of the gadolinium oxide to change from 1.7 to 2.1, thereby changing the plasmon effect between the top metal rod 5 and the bottom metal rod 4, thereby changing the original CD signal, thereby realizing the electrical regulation of the CD signal.

[0090] The interaction between the bottom metal rod 4 of the present invention and the incident light will excite localized surface plasmons. From the free electron model and the Drude model, it can be known that the relationship between the refractive index of a metal and its dielectric constant is ε 1 =n 2 -k 2 ,ε 2 =2nk, where ε 1 ,ε 2 are the real and imaginary parts of the dielectric constant, respectively, and n and k are the real and imaginary parts of the refractive index, respectively. So when voltage is applied, hydrogen protons completely fill Pd to become PdH x After that, the change of its refractive index will affect the change of dielectric constant, thus changing the localized plasmon effect between metal and medium, and then the absorption rate of RCP and LCP of the structure will change, realizing the electrical control of CD signal.

[0091] The present invention utilizes gold and gadolinium oxide to generate H protons under an external voltage. The H protons move downward under the drive of the external electric field to hydrogenate the bottom metal rod 4, thereby changing the refractive index of the bottom metal rod 4, changing the plasmon effect between the original top metal rod 5 and the bottom metal rod 4, and further changing the peak value and peak position of the CD signal, thereby realizing electrical regulation of the CD signal. The method is simple, the operation is controllable, and the cost is low.

[0092] Example 6

[0093] The application of the nanodevice for electrically controlling chiral effect described in Example 4 is used to realize the electrical control of CD signals, including:

[0094] In this embodiment, the bottom electrode 1 is connected to the negative pole of the power supply, and the top electrode 6 is connected to the positive pole of the power supply; when the external voltage is 0V, the top metal rod 5 and the bottom metal rod 4 form an asymmetric right-handed structure, such as Figure 5 As shown, the absorption peak for RCP is 0.92, the peak position is 933nm, and the absorption peak for LCP is 0.58, the peak position is 811nm, resulting in Figure 5 The CD signal shown in the figure has a peak value of -0.56 and a peak position of 958nm. When the external voltage is 6V, the top metal rod 5Au and the gadolinium oxide in the dielectric layer 3 catalyze the decomposition of water molecules in the air to produce H protons and oxygen under the action of the voltage. Under the action of the electric field, the H protons move from the top of the dielectric layer 3 to the bottom, and in the process of the H protons moving, the Pd material of the bottom metal rod 4 is hydrogenated to form PdH x , changing its refractive index, and making the refractive index of the dielectric layer 3 change from 1.7 to 2.1, so that the plasmon effect formed by the top metal rod 5 and the bottom metal rod 4 changes, such as Figure 6 As shown in FIG. 1 , the absorption rate of the structure for RCP and LCP is different from the absorption rate when a 0V voltage is applied, thereby changing the original CD signal. Figure 7 As shown in the figure, the CD signal spectrum of applying 0V voltage and 6V voltage twice, from Figure 7 It can be seen that the peak position of the CD signal is red-shifted from the original 958nm to 1247nm, and the peak value is reduced from the original 0.56 to 0.46, realizing the electrical regulation of the CD signal. The present invention utilizes gold and gadolinium oxide to generate H protons under the action of an external voltage. The H protons move downward under the drive of an external electric field to hydrogenate the bottom metal rod 4Pd to form PdH x , thereby changing the refractive index of the bottom metal rod 4. At the same time, due to the injection of H protons into the gadolinium oxide in the dielectric layer 3, its refractive index also changes from the original 1.7 to 2.1, thereby changing the plasmon effect formed by the original top metal rod 5 and the bottom metal rod 4, and realizing the electrical regulation of the CD signal.

Claims

1. A nanodevice for electrically controlling chiral effects, It is characterized in that It comprises a substrate, a plurality of control units with the same structure, a top electrode and a bottom electrode; the plurality of control units are periodically arranged on the substrate, and the top electrode and the bottom electrode are respectively arranged on both sides of the plurality of control units; Each control unit includes a metal reflective layer, a bottom metal rod, a dielectric layer and a top metal rod; the metal reflective layer is arranged on the substrate, the dielectric layer is arranged on the metal reflective layer, the bottom metal rod is arranged in the dielectric layer and close to the metal reflective layer, the top metal rod is arranged on the dielectric layer, the metal reflective layer is connected to the bottom electrode, and the top metal rod is connected to the top electrode; the top metal rod and the bottom metal rod form an asymmetric chiral metal nanostructure in space; The dielectric layer is a material that can conduct hydrogen protons.

2. A nanodevice for electrically controlling chiral effects according to claim 1, It is characterized in that The dielectric layer is gadolinium oxide, tungsten trioxide or perovskite-type oxide.

3. The nanodevice for electrically controlling chiral effect according to claim 1, It is characterized in that The refractive index of the dielectric layer is 1.6-1.

8.

4. The nanodevice for electrically controlling chiral effect according to claim 3, It is characterized in that The refractive index of the dielectric layer is 1.

7.

5. The nanodevice for electrically controlling chiral effect according to claim 1, It is characterized in that The bottom metal rod is made of a material that can be hydrogenated.

6. The nanodevice for electrically controlling chiral effect according to claim 1, It is characterized in that The material of the bottom metal rod is palladium Pd, magnesium Mg, platinum Pt, yttrium Y or graphite.

7. The nanodevice for electrically controlling chiral effect according to claim 1, It is characterized in that The metal reflective layer, the top metal rod, the top electrode and the bottom electrode are all made of gold Au material.

8. The nanodevice for electrically controlling chiral effect according to claim 1, It is characterized in that The bottom metal rod is arranged in the dielectric layer directly below the top metal rod. The bottom metal rod is rotated 45 degrees counterclockwise with the Z axis as the central axis, forming spatial asymmetry with the top metal rod, and its structural shape is a cross-rod structure.

9. The nanodevice for electrically controlling chiral effect according to claim 1, It is characterized in that The thickness of the metal reflective layer is 30-200 nm; The thickness of the dielectric layer is 140-160nm; The width of the top metal rod and the bottom metal rod are both 90-110 nm, the height of the top metal rod and the bottom metal rod are both 20-40 nm, the length of the bottom metal rod is 260-340 nm, and the length of the top metal rod is 350-450 nm; The period of the control unit is 350-450nm, which is equal to the length of the top metal rod; The distance between the lower surface of the bottom metal rod and the upper surface of the metal reflective layer is 10-30 nm, and the distance between the upper surface of the bottom metal rod and the upper surface of the dielectric layer is 110-90 nm; The distance between the lower surface of the top metal rod and the upper surface of the bottom metal rod is 110-90 nm, and the angle between the horizontal planes of the top metal rod and the bottom metal rod is 0-90°.

10. The nanodevice for electrically controlling chiral effect according to claim 1, It is characterized in that The thickness of the metal reflective layer is 100 nm; The thickness of the dielectric layer is 150nm; The width of the top metal rod and the bottom metal rod are both 100 nm, the height of the top metal rod and the bottom metal rod are both 30 nm, the length of the bottom metal rod is 300 nm, and the length of the top metal rod is 400 nm; The period of the control unit is 400nm, which is equal to the length of the top metal rod; The distance between the lower surface of the bottom metal rod and the upper surface of the metal reflective layer is 20 nm, and the distance between the upper surface of the bottom metal rod and the upper surface of the dielectric layer is 100 nm; The distance between the lower surface of the top metal rod and the upper surface of the bottom metal rod is 100 nm, and the angle between the horizontal planes of the top metal rod and the bottom metal rod is 45°.

11. Application of the nanodevice for electrically regulating chiral effect according to any one of claims 1 to 10, It is characterized in that Used to realize electrical control of CD signals, including: The bottom electrode is externally connected to a negative power source, and the top electrode is externally connected to a positive power source; When the external voltage is 0V or disconnected, a CD signal is generated; When the external voltage is 3V-6V, the top metal rod material and the dielectric layer catalyze the decomposition of water molecules in the air to produce H protons and oxygen under the action of voltage. Under the action of the electric field, the H protons move from the top of the dielectric layer to the bottom, and encounter the bottom metal rod material during the movement. The H protons hydrogenate the bottom metal rod and change the refractive index of the bottom metal rod. At the same time, the hydrogen protons in the gadolinium oxide body also cause the refractive index of gadolinium oxide to change from 1.7 to 2.1, thereby changing the plasmon effect between the top metal rod and the bottom metal rod, thereby changing the original CD signal and realizing electrical regulation of the CD signal.

Images