Infrared optical modulator and infrared optical modulation method thereof

Abstract

The invention provides an infrared optical modulator and an infrared optical modulation method thereof, the infrared optical modulator comprises a reflecting layer, a dielectric layer, a light modulation layer and a metamaterial layer which are laminated, conductive and attached, and the reflecting layer is attached to the bottom surface of the dielectric layer; the metamaterial layer and the light modulation layer are attached to each other, and any one of the metamaterial layer and the light modulation layer is attached to the top surface of the dielectric layer, so that a resonant cavity is formed by the metamaterial layer, the dielectric layer and the reflecting layer; the reflecting layer and the light modulation layer are electrically connected so as to adjust the carrier concentration in the light modulation layer and change the resonance absorption characteristic of the resonant cavity. And dynamic modulation of the infrared wave absorption frequency and absorption efficiency of the metamaterial device is realized.

Description

Technical Field

[0001] The present invention relates to the field of optical modulation technology, and in particular to an optical modulator for performing light wave modulation in an infrared band and an infrared optical modulation method thereof. Background Art

[0002] The infrared band is extremely relevant to some important physical, chemical and biological mechanisms (such as the superconducting energy gap and the dynamic mechanism of proteins), and has therefore attracted extensive attention from researchers [1-2]. Research in the infrared to far-infrared band is still a less studied area than in all other bands. Expanding the ability and means to control the infrared band is of great significance for both scientific research and practical applications in the future.

[0003] Metamaterial structures are a new type of artificial material, usually composed of periodic two-dimensional or three-dimensional structures. The design of metamaterials has a large degree of freedom. The symmetry of the structure, the parameters in the unit structure, the arrangement of the structure array, etc. will affect the spatial distribution of surface plasmons, and thus affect the modulation ability of electromagnetic waves. Based on the above characteristics, the use of metamaterial structures can effectively realize the detection and regulation of infrared light, which has greatly promoted the research and development in the infrared field [3].

[0004] Currently, the perfect absorber based on metamaterial structure has become an emerging research hotspot as an absorption device for regulating far-field infrared light.

[0005] Metamaterial perfect absorber (MPA) is an optical absorption device based on metamaterial structure, which can achieve nearly 100% absorption of light waves in a specific working band. Since the metamaterial perfect absorber was designed in 2008[4], its performance and characteristics have been continuously improved and enhanced by researchers. In recent years, there have been a lot of theoretical and experimental research results. At present, the main optimization direction of metamaterial perfect absorbers is to develop towards high absorption, multi-band or wide-band, and the use of external means for modulation.

[0006] However, since it is often difficult to further change the device parameters of metamaterial devices after the structural parameters are determined and samples are prepared, the flexibility, adjustability and application scenarios of the devices are limited.

[0007] References

[0008] [1]WILLIAMS G P.Filling the THz gap-high power sources andapplications[J].Rep.Prog.Phys.2006,69:301-326

[0009] [2]FERGUFON B,ZHANG X.Materials for terahertz science and technology[J].Nat.Mat.2002,1:26-33.

[0010] [3]CHEN H,O'HARA JF,et al.Manipulation of terahertz radiation usingmetamaterials[J].Laser Photon.Rev.2011,5:513-533.

[0011] [4]LANDY NI,SAJUYIGBE S,MOCK JJ,et.al.Perfect metamaterial absorber[J].Phys.Rev.Lett,2008,100:207402. Summary of the invention

[0012] To this end, the main purpose of the present invention is to provide an infrared optical modulator and an infrared optical modulation method thereof to solve the problems mentioned in the background technology and realize dynamic modulation of the infrared wave absorption frequency and absorption efficiency of the metamaterial device.

[0013] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided an infrared optical modulator, comprising: a reflective layer, a dielectric layer, a light modulation layer and a metamaterial layer which are stacked and conductively bonded, wherein the reflective layer is bonded to the bottom surface of the dielectric layer; the metamaterial layer and the light modulation layer are bonded to each other, and either of them is bonded to the top surface of the dielectric layer, so as to form a resonant cavity through the metamaterial layer, the dielectric layer and the reflective layer; the reflective layer and the light modulation layer are electrically connected to adjust the carrier concentration in the light modulation layer, thereby changing the resonant absorption characteristics of the resonant cavity.

[0014] In a possible preferred embodiment, the infrared optical modulator further includes: a substrate layer, which is arranged at the bottom of the reflective layer.

[0015] In a possible preferred embodiment, a first electrode is disposed on the light modulation layer, and a second electrode is disposed on the extended exposed portion of the reflective layer.

[0016] In a possible preferred embodiment, the reflective layer is made of either gold or silver with a thickness of ≥10 nm.

[0017] In a possible preferred implementation, the dielectric layer is made of silicon nitride, or any dielectric material having a dielectric constant close to that of silicon nitride, and the thickness of the dielectric layer is 120 nm to 300 nm.

[0018] In a possible preferred embodiment, the light modulation layer is made of any of the following materials: single-layer graphene, or transition metal sulfide MX2, where M = Mo, W, Zr; X = S, Se, Te, or phosphorene, hexagonal boron nitride (h-BN), or a multilayer thin film structure composed of the above materials.

[0019] In a possible preferred embodiment, the metamaterial layer is composed of a single or several cross unit structure arrays, the material is made of any one of gold, silver or titanium nitride, and the thickness is 20 to 100 nm.

[0020] In a possible preferred embodiment, the arm length of each of the cross unit structures is 0.2-0.4 μm, the arm width is 1.05-1.35 μm, and the structural period is 2.3 μm.

[0021] In order to achieve the above object, according to another aspect of the present invention, corresponding to the infrared optical modulator provided above, the present invention also provides an infrared optical modulation method, the steps of which include:

[0022] Grounding or maintaining a zero volt bias on the optical modulation layer;

[0023] A bias voltage is applied to the reflective layer to adjust the carrier concentration in the light modulation layer until the resonant cavity is controlled to achieve the expected resonant absorption characteristics.

[0024] In a possible preferred embodiment, the bias voltage applied to the reflective layer ranges from -30V to +30V, or the bias voltage range is appropriately narrowed or widened.

[0025] The infrared optical modulator and infrared optical modulation method provided by the present invention are cleverly designed to form a resonant cavity composed of a metamaterial layer G, a dielectric layer C and a reflective layer B. When the effective impedance of the three-layer structure resonant cavity matches the impedance of free space at a specific optical frequency, the resonant cavity will resonantly absorb the electromagnetic waves in the frequency band, so that the device of the present invention can achieve near-perfect absorption in the mid-infrared band (near 60THz). At the same time, through the hierarchical structure design between the devices, when the reflective layer B and the optical modulation layer D are connected to the power supply, the Fermi level of the optical modulation layer D can be adjusted according to the different voltages applied, thereby changing the carrier concentration in the layer, and then realizing the change of the resonant absorption characteristics of the resonant cavity (such as the resonant absorption frequency and absorptivity), thereby realizing dynamic modulation of the infrared wave absorption performance, so as to enhance the flexibility of the device and adapt to and expand more application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0027] Figure 1 It is a schematic diagram of the structure of the infrared optical modulator of the present invention;

[0028] Figure 2 It is a schematic diagram of the array structure and the cross unit structure of the metamaterial layer in the infrared optical modulator of the present invention;

[0029] Figure 3 It is a side view structural schematic diagram of the infrared optical modulator of the present invention in a power-on state;

[0030] Figures 4 to 5 A schematic diagram of simulation and test data of the infrared optical modulator absorption spectrum affected by the metamaterial layer formed by a cross unit structure array in different value ranges in the infrared optical modulator of the present invention;

[0031] Figure 6 is an absorption characteristic curve diagram of the infrared optical modulator of the present invention under exemplary electrical modulation;

[0032] Figure 7 It is a schematic diagram of the steps of the infrared optical modulation method of the present invention.

[0033] Description of Reference Numerals

[0034] Substrate layer A, reflection layer B, dielectric layer C, light modulation layer D, metamaterial layer G, first electrode E, second electrode F. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solution of the present invention, the specific technical solution of the present invention will be clearly and completely described in conjunction with the embodiments below to help those skilled in the art further understand the present invention. Obviously, the embodiments described in this case are only embodiments of a part of the present invention, not all of the embodiments. It should be pointed out that for those of ordinary skill in the art, the embodiments in this application and the features in the embodiments can be combined with each other without departing from the concept of the present invention and without conflicting with each other. Based on the embodiments in the present invention, all other embodiments obtained without creative work by those of ordinary skill in the art should belong to the disclosure and protection scope of the present invention.

[0036] In addition, the terms "first", "second", "S100", "S200", etc. in the specification, claims and drawings of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the features used in this way can be interchanged where appropriate, so that the embodiments of the present invention described here can be implemented in an order other than those described here. At the same time, the stages recorded in each step are not mandatory to be implemented in the same step. It should be understood that the implementation order of the contents in each step stage can be adjusted and interchanged without violating the inventive concept, so that the step embodiments of the present invention described here can be implemented in an order other than those described here. In addition, the terms "including" and "having" and any of their variations in the present invention are intended to cover non-exclusive inclusions. Unless otherwise clearly specified and limited, the terms "set", "layout", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in this case can be understood according to specific circumstances and in combination with the prior art.

[0037] In order to achieve dynamic modulation of infrared wave absorption frequency and absorption efficiency of metamaterial devices, such as Figures 1 to 6 As shown, the present invention provides an infrared optical modulator, an example of which includes: a reflective layer B, a dielectric layer C, a light modulation layer D and a metamaterial layer G which are sequentially stacked and conductively bonded.

[0038] In this example, the reflective layer B is preferably composed of gold or silver with a thickness of ≥10 nm, which is mainly used to prevent light from penetrating.

[0039] The dielectric layer C is mainly used for infrared absorption, and is preferably made of 120nm-300nm silicon nitride, or any dielectric material with a dielectric constant close to that of silicon nitride. For example, the best parameters of the dielectric layer C can be selected around 200nm, and the interval end values ​​(120nm and 300nm) can roughly guarantee an absorption rate of 60%.

[0040] The optical modulation layer D is mainly used for dynamically adjusting the resonant absorption frequency and absorptivity, and is preferably composed of any of the following materials: a single-layer graphene, or a transition metal sulfide MX2, wherein M=Mo, W, Zr; X=S, Se, Te, or phosphorene, hexagonal boron nitride (h-BN), or a multilayer thin film structure composed of the above materials, such as a three-layer structure composed of h-BN / graphene / h-BN.

[0041] The metamaterial layer G is mainly used to modulate the resonant absorption characteristics of infrared light. It is preferably composed of a single or several cross unit structure arrays, and the entire array structure is made of gold, silver or titanium nitride with a thickness of 20 to 100 nm. For example, in the case of a cross array structure composed of gold, the interval end values ​​(20 nm and 100 nm) can approximately guarantee an absorption rate of 70%.

[0042] Under this structure, a resonant cavity structure can be formed through the metamaterial layer G, the dielectric layer C and the reflective layer B to resonantly absorb the infrared light selected by the metamaterial parameters. The principle is that when the effective impedance of the resonant cavity formed by the three-layer structure reaches a mutual match with the impedance of the free space, the resonant cavity will resonantly absorb the electromagnetic waves in this frequency band. Theoretically, under the optimal structure, perfect absorption of infrared light in a specific frequency band can be achieved, that is, the absorption efficiency reaches 100%.

[0043] Generally speaking, once the metamaterial structure is determined, the absorption characteristics of the device are fixed. Therefore, in order to enable the present invention to perform further electrical modulation on the basis of near-perfect absorption and dynamically adjust the absorption efficiency and absorption frequency band, an optical modulation layer D is specially provided in this example to adjust the absorption characteristics of the device in real time by applying voltage, thereby realizing dynamic adjustment of the resonant absorption frequency and absorption rate.

[0044] Specifically, if Figure 1 , Figure 3 As shown, in an optional embodiment, in order to increase the conductivity and connectivity of the reflective layer B and the light modulation layer D, a first electrode E may be disposed on the light modulation layer D, and a second electrode F may be disposed on the extended exposed portion of the reflective layer B. The first electrode and the second electrode may be made of gold or other materials with good conductivity.

[0045] The first electrode E and the metamaterial layer G can be in the same layer and closely attached to the light modulation layer D. The first electrode E can be made of gold or other materials with good electrical conductivity. The second electrode F can be omitted when it is not necessary. For example, when the reflective layer B is thin, the second electrode F can be provided to ensure good connectivity of the circuit when the device is working. In addition, if the reflective layer B has Figure 1 or Figure 3 The exposed area of ​​the step shown can generally also be used as an electrode, but it needs to maintain good electrical contact with the reflective layer B.

[0046] With this arrangement, the modulation layer D is grounded or maintained at a zero volt bias through the above-mentioned first electrode E and second electrode F, and a bias is applied to the reflective layer B at the same time, so that the Fermi level of the optical modulation layer D, such as graphene, can be adjusted, thereby changing the carrier concentration in the layer, and at the same time affecting the resonant absorption characteristics (including resonant absorption frequency and absorption rate) of the resonant cavity composed of the metamaterial layer G, the dielectric layer C and the reflective layer B, thereby achieving dynamic modulation of the infrared wave absorption frequency and absorption efficiency of the device according to the different applied voltages.

[0047] In addition, in an optional embodiment, the positions of the optical modulation layer D and the metamaterial layer G can be swapped, and it is only necessary to ensure that the two layers have good electrical contact. After the swap, theoretically, the absorption and modulation performance of the device will not be affected. Therefore, those skilled in the art can perform replacement according to actual needs.

[0048] Furthermore, since there is a corresponding relationship between the specific absorption characteristics (absorption frequency and absorption rate) of the resonant cavity and the specific parameters of the cross unit array structure, when the effective impedance of the three-layer structure (resonant cavity) composed of the metamaterial layer G, the dielectric layer C and the reflective layer B matches the impedance of free space at a specific optical frequency, the resonant cavity will resonate and absorb electromagnetic waves in this frequency band.

[0049] For this reason, Figure 2 As shown, in a preferred embodiment, in the metamaterial layer G, the structural parameters of each unit structure in the cross unit array can be set to be the same. Figure 2 As shown on the right, H is the period of the cross unit structure, and the preferred parameter is: 2.3μm; I is the arm length parameter of the cross unit structure, and the preferred length range is: 0.2~0.4μm; J is the arm width parameter of the cross unit structure, and the length range is: 1.05~1.35μm.

[0050] like Figures 4 to 5 As shown in FIG. 1 , the specific value of HIJ can be changed according to the above parameter range, and the performance of the device after the change will also change accordingly. However, within the above range, a relatively good absorption characteristic (i.e., the absorption efficiency reaches more than 70%) can be guaranteed. The theoretical results are shown in FIG. Figure 4 shown.

[0051] In addition, it is worth mentioning that, through the structural scheme of the above-mentioned device, the cross unit array structure of the metamaterial layer G can be prepared as a square area with a side length of 50 μm, so the working area size can be miniaturized, so as to more flexibly adapt to various device sizes. At the same time, those skilled in the art can also adaptively adjust the overall area and shape of the array according to the size of the incident light spot (the specific number of cross unit structures in the area can be determined by the size of the area).

[0052] Further, in order to reduce the difficulty of device fabrication, in an alternative embodiment, a substrate layer A may be provided at the bottom of the reflective layer B. The substrate layer A may be made of materials such as silicon wafers, transparent substrates (such as glass), etc. The fabrication method of the device is generally preferably a standard micro-nano processing process flow. Meanwhile, during the fabrication process, layers B, C, D, E, F, and G may be fabricated on the substrate layer A (the fabrication sequence may vary depending on the specific fabrication process), or the reflective layer B and layers D, G, and E may be respectively fabricated on both sides of the window of the suspended dielectric layer C. At this time, the reflective layer B will simultaneously have the functions of a reflective layer and an electrode. Neither method will change the optical absorption modulation characteristics of the present device, and those skilled in the art can choose to implement it.

[0053] The infrared optical modulator fabricated through the above-described embodiment can theoretically achieve near-perfect absorption in the mid-infrared band (near 60 THz) and simultaneously support dynamic modulation of the absorption performance. In addition, if the device of this example is fabricated on a suspended silicon nitride (Si3N x where 0 < x <= 4) window, the overall thickness of the device can be maintained at about 300 nm, which is much smaller than the resonant absorption wavelength. Therefore, the overall thickness can be made very thin and can be attached to the required surface for fabrication, making it suitable for application scenarios with strict spatial limitations.

[0054] Experimental Example

[0055] 1. As Figure 3 shown, first, without applying any bias voltage, the absorption properties of the infrared optical modulator sample of the above example were measured:

[0056] (1) Fix the sample on the sample stage, and do not apply voltage to both the first electrode E and the reflective layer B (or the second electrode F);

[0057] (2) Let the infrared light K be focused on the array structure of the metamaterial layer G;

[0058] (3) Use a Fourier transform infrared spectrometer to measure the reflection spectrum of the device;

[0059] (4) Repeat the above steps to measure device samples with different structural parameters.

[0060] In this example, 5 samples were selected for testing (the test results are as Figure 5 shown), and the parameters of the cross-shaped unit structures of each sample were as follows:

[0061] The first group: arm length 1.15 μm, arm width 0.2 μm;

[0062] The second group: arm length 1.25 μm, arm width 0.2 μm;

[0063] The third group: arm length 1.25 μm, arm width 0.3 μm;

[0064] Group 4: arm length 1.35 μm, arm width 0.2 μm;

[0065] Group 5: arm length 1.35μm, arm width 0.3μm.

[0066] Since the transmission of each sample is zero, the absorbance and reflectance of the sample will follow the following relationship:

[0067] Absorption = 1 – reflectivity.

[0068] According to the above relationship, Figure 5 The test data shown above can be used to obtain the absorption spectra of the above samples. It can be seen that each sample device has achieved nearly 100% absorption of infrared light of a specific frequency. At the same time, samples with different parameter structures have different absorption characteristics for infrared light. Among them, the sample device of the metamaterial layer G of the cross unit structure array with the parameters of arm length 1.25μm and arm width 0.3μm has a frequency of 2013cm -1 The absorption efficiency of infrared light exceeds 96.3%.

[0069] 2. Perform voltage modulation on the device sample, and take the sample device of metamaterial layer G with a cross unit structure array with an arm length of 1.25μm and an arm width of 0.3μm as an example to test the absorption properties of the sample device:

[0070] (1) Fix the sample on the sample stage according to Figure 3 As shown, the first electrode E is kept grounded or 0V is applied (connected to the ground terminal of the voltage source meter), and a voltage of -8V (i.e., V G =-8V)(connected to the power line output terminal of the voltage source meter);

[0071] (2) measuring the reflectance spectrum of the sample according to the measurement method ((2)-(3)) described above when no bias voltage is applied;

[0072] (3) Change the voltage applied to the reflective layer B (or the second electrode F) and measure the reflection spectrum of the sample again. Repeat this process to complete the test when the bias voltage is 0V, 8V, and 16V. The absorption characteristic curve of the sample under electrical modulation is shown in Figure 6 shown.

[0073] According to the test results, after applying different voltages to the reflective layer B of the sample, the absorption characteristics of the sample, especially the absorption frequency and absorption rate, will change with the change of voltage, thereby realizing dynamic modulation of infrared light. And according to the above experiments, it can be seen that the infrared optical modulator of this example consumes very little energy in the working state, and does not generate energy consumption when working in the non-electrical modulation state; in the electrical modulation state, the actual energy consumption is almost negligible because the current flowing through is very small.

[0074] On the other hand, Figure 7 As shown, corresponding to the above infrared optical modulator example, the present invention also provides an infrared optical modulation method, the steps of which include:

[0075] Ground the optical modulation layer D or maintain a zero volt bias;

[0076] A bias voltage (with no polarity restriction) is applied to the reflective layer B to adjust the carrier concentration in the optical modulation layer D until the resonant cavity is controlled to achieve the expected resonant absorption characteristics.

[0077] In an optional example, the bias voltage applied to the reflective layer B generally ranges from -30V to +30V.

[0078] In summary, the infrared optical modulator and infrared optical modulation method provided by the present invention are cleverly designed to form a resonant cavity composed of a metamaterial layer G, a dielectric layer C and a reflective layer B. When the effective impedance of the three-layer structure resonant cavity matches the impedance of free space at a specific optical frequency, the resonant cavity will resonate and absorb the electromagnetic waves in this frequency band, so that the device of the present invention can achieve near-perfect absorption in the mid-infrared band (near 60THz). At the same time, through the hierarchical structure design between devices, when the reflective layer B and the optical modulation layer D are connected to the power supply, the Fermi level of the optical modulation layer D can be adjusted according to the different voltages applied, thereby changing the carrier concentration in the layer, and then realizing the change of the resonant absorption characteristics of the resonant cavity (such as the resonant absorption frequency and absorptivity), thereby realizing dynamic modulation of the infrared wave absorption performance, so as to enhance the flexibility of the device and adapt to and expand more application scenarios.

[0079] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is only limited by the claims and their full scope and equivalents. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0080] Those skilled in the art can understand that, in addition to implementing the system, device, unit and its various modules provided by the present invention in a purely computer-readable program code, it is entirely possible to implement the same program in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers and embedded microcontrollers by logically programming the method steps. Therefore, the system, device and its various modules provided by the present invention can be considered as a hardware component, and the modules included therein for implementing various programs can also be regarded as structures within the hardware component; the modules for implementing various functions can also be regarded as both software programs for implementing the method and structures within the hardware component.

[0081] In addition, all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including a number of instructions to enable a single-chip microcomputer, a chip or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0082] In addition, various implementation modes of the embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed by the embodiments of the present invention.

Claims

1. An infrared optical modulator, comprising: A reflective layer, a dielectric layer, a light modulation layer and a metamaterial layer are stacked and conductively bonded, wherein the reflective layer is bonded to the bottom surface of the dielectric layer; the metamaterial layer and the light modulation layer are bonded to each other, and either of them is bonded to the top surface of the dielectric layer, so as to form a resonant cavity through the metamaterial layer, the dielectric layer and the reflective layer; the reflective layer and the light modulation layer are electrically connected to adjust the carrier concentration in the light modulation layer and change the resonance absorption characteristics of the resonant cavity.

2. The infrared optical modulator according to claim 1, further comprising: The substrate layer is arranged at the bottom of the reflective layer. 3 . The infrared optical modulator according to claim 1 , wherein a first electrode is disposed on the light modulation layer, and a second electrode is disposed on the extended exposed portion of the reflective layer. 4 . The infrared optical modulator according to claim 1 , wherein the reflective layer is made of either gold or silver with a thickness of ≥10 nm. 5 . The infrared optical modulator according to claim 1 , wherein the dielectric layer is made of any of the following materials: silicon nitride, or any dielectric material having a dielectric constant close to that of silicon nitride, and the thickness of the dielectric layer is 120 to 300 nm.

6. An infrared optical modulator according to claim 1, wherein the light modulation layer is made of any of the following materials: a single-layer graphene, or a transition metal sulfide MX2, where M = Mo, W, Zr; X = S, Se, Te, or phosphorene, hexagonal boron nitride, or a multilayer thin film structure composed of the above materials.

7. The infrared optical modulator according to claim 1, wherein the metamaterial layer is composed of a single or several cross unit structure arrays, the material is made of any one of gold, silver or titanium nitride, and the thickness is 20 to 100 nm.

8. The infrared optical modulator according to claim 7, wherein the arm length of each of the cross unit structures ranges from 0.2 to 0.4 μm, the arm width ranges from 1.05 to 1.35 μm, and the structural period is 2.3 μm.

9. An infrared optical modulation method, used for the infrared optical modulator according to any one of claims 1 to 8, comprising the steps of: Grounding or maintaining a zero volt bias on the optical modulation layer; A bias voltage is applied to the reflective layer to adjust the carrier concentration in the light modulation layer until the resonant cavity is controlled to achieve the expected resonant absorption characteristics.

10. The infrared optical modulation method according to claim 9, wherein the bias voltage applied to the reflective layer is in the range of: -30V to +30V, or appropriately narrow or widen the bias range.

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