An adjustable absorber

Abstract

The present invention provides an adjustable absorber, comprising: a substrate, a metal layer, a first dielectric layer, a first phase change layer, a second dielectric layer, a second phase change layer, a third dielectric layer, and an anti-reflection layer, arranged sequentially from bottom to top; the substrate can be a flexible substrate or a rigid substrate; the phase change material in the first phase change layer and the phase change material in the second phase change layer undergo a transition between a crystalline state and an amorphous state under the stimulation of a thermal field, an electric field, or a laser pulse, resulting in a phase change, and light regulation is achieved through changes in the refractive index and extinction coefficient before and after the phase change; the metal layer generates sufficient heat under electrical stimulation, causing the phase change material in the first phase change layer and the phase change material in the second phase change layer to change their respective reflectivity and extinction coefficient when they transition between the amorphous state and the crystalline state, thereby achieving light regulation and further realizing a black state and a gray state. The present invention realizes a multilayer thin-film structure absorber with dynamic adjustment and simple processing.

Description

Technical Field

[0001] The present invention relates to the technical field of phase change materials, and in particular to an adjustable absorber. Background Art

[0002] Perfect light absorbers, a common optical component at optical frequencies, are crucial in a variety of applications. In solar thermal harvesting, broadband absorption covering a large portion of the solar spectrum is one of the most important clean energy sources. In compact imaging spectrometers based on multichannel filters, perfect light absorbers effectively prevent crosstalk between adjacent channels in the aerospace and semiconductor industries.

[0003] In photonic devices, perfect absorbers can be used to prevent reflection, scattering, and interference of light waves, improving device performance and efficiency. In photodetectors, perfect absorbers can provide efficient light absorption and enhance the detection sensitivity of optical signals. In optical sensors, perfect absorbers can be used in various optical sensors, such as gas sensors, biosensors, and chemical sensors, to detect and analyze target substances through light absorption. In imaging systems, perfect absorbers can be used to reduce crosstalk between different channels, improving imaging quality and resolution. In lasers, perfect absorbers can be used to absorb the residual light beam generated by the laser, reducing light loss and reflection. In the field of optical communications, perfect absorbers can be used in fiber optic connections and optical signal processing, improving the transmission efficiency and quality of communications.

[0004] In recent years, there has been tremendous interest in efficient light absorption in the visible and near-infrared (NIR) regions, which has potential applications in detection, imaging, photovoltaics, and other fields. Among all absorber designs, broadband absorbers based on metamaterials and transformation optics have been widely studied and developed, and their absorption effect is enhanced by exciting surface plasmon resonance. In particular, conical structures composed of alternating metal and dielectric films have been widely discussed, which can be regarded as hyperbolic metamaterial (HMM) waveguides with different widths. However, all of the above broadband absorbers require precise control or complex procedures, including multiple steps such as nanofabrication, reactive ion etching, electron beam lithography, or focused ion beam etching, which severely limits their feasibility in practical applications, especially over relatively large areas. Summary of the Invention

[0005] The present invention provides an adjustable absorber to solve the defects of absorbers in the prior art that require precise control or complex procedures, and realizes a multi-layer thin film structure absorber with dynamic adjustability and simple process.

[0006] The present invention provides an adjustable absorber, comprising:

[0007] A substrate, a metal layer, a first dielectric layer, a first phase change layer, a second dielectric layer, a second phase change layer, a third dielectric layer and an anti-reflection layer are arranged in sequence from bottom to top;

[0008] The substrate is a flexible substrate or a rigid substrate;

[0009] The phase change material in the first phase change layer and the phase change material in the second phase change layer undergo a transition between a crystalline state and an amorphous state under the stimulation of a thermal field, an electric field or a laser pulse, resulting in a phase change, and light is controlled by the changes in the refractive index and the extinction coefficient before and after the phase change;

[0010] The metal layer generates sufficient heat under electrical excitation, so that the reflectivity and extinction coefficient of the phase change material of the first phase change layer and the phase change material of the second phase change layer change when they transform between the amorphous state and the crystalline state, thereby achieving light regulation and further realizing the black state.

[0011] According to the adjustable absorber provided by the present invention, the thickness of the first phase change layer and the second phase change layer range from 3 nm to 100 nm respectively;

[0012] The thickness of the anti-reflection layer ranges from 0 nm to 500 nm, and the refractive index of the anti-reflection layer is greater than the refractive index of the third dielectric layer;

[0013] The K values of the first dielectric layer, the second dielectric layer, the third dielectric layer and the anti-reflection layer are less than 1.

[0014] According to the adjustable absorber provided by the present invention, the first phase change layer and the second phase change layer have different phase change thresholds.

[0015] According to an adjustable absorber provided by the present invention, the phase change material of the first phase change layer is an alloy compound composed of a Group VI element and a Group III to V element and doped with a Group Ib element;

[0016] The phase change material of the second phase change layer is an alloy compound composed of a VI main group element and elements of groups III to V and doped with an Ib main group element.

[0017] According to an adjustable absorber provided by the present invention, the phase change material of the first phase change layer includes one or more of GeTe, SbTe, BiTe, InSb, InSe, GeSb, SbSe, GaSb, GeSbTe, AgInSbTe, InSbTe, AgSbTe, SiTe, SnTe and SnSb; wherein the atomic percentage of each phase change material is adjustable;

[0018] The phase change material of the second phase change layer includes one or more of GeTe, SbTe, BiTe, InSb, InSe, GeSb, SbSe, GaSb, GeSbTe, AgInSbTe, InSbTe, AgSbTe, SiTe, SnTe and SnSb; wherein the atomic percentage of each phase change material is adjustable.

[0019] According to an adjustable absorber provided by the present invention, the metal layer is a simple substance formed by one of the elements of main groups III to V or a compound composed of multiple elements in any proportion.

[0020] According to an adjustable absorber provided by the present invention, the metal layer is ITO, Ag, Au or W, and the thickness of the metal layer is greater than 50 nm.

[0021] According to an adjustable absorber provided by the present invention, the anti-reflection layer is one or more of SiO2, TiO2, MgF2, Si3N4, ITO and AlN, and the thickness of the anti-reflection layer is 5nm to 100nm.

[0022] According to an adjustable absorber provided by the present invention, the first dielectric layer is one or more of SiO2, HfO, Al2O3, ZnO, In2O3, TiO2, Si3N4 and MgF2, and the thickness of the first dielectric layer is 1 nm to 500 nm;

[0023] The second dielectric layer is one or more of SiO2, HfO, Al2O3, ZnO, In2O3, TiO2, Si3N4 and MgF2, and the thickness of the second dielectric layer is 1 nm to 500 nm;

[0024] The third dielectric layer is one or more of SiO2, HfO, Al2O3, ZnO, In2O3, TiO2, Si3N4 and MgF2, the thickness of the third dielectric layer is 1nm to 500nm, and the n value of the third dielectric layer is less than the n value of the anti-reflection layer.

[0025] According to the adjustable absorber provided by the present invention, the manufacturing steps of the flexible substrate include:

[0026] Use a spin coater to evenly coat the PDMS spin coating liquid on the rigid silicon substrate;

[0027] After uniform coating, the film was solidified by passing through a multi-gradient temperature annealing furnace, wherein the temperature gradient was set to 100°C for 10 min, 150°C for 10 min, 200°C for 10 min, 250°C for 10 min, 300°C for 10 min, 350°C for 10 min, 350°C for 10 min, and 400°C for 10 min, and then cooled at a cooling rate of 1°C / min to obtain a flexible thin film PDMS;

[0028] The flexible thin film PDMS is cleaned by a plasma cleaning machine to obtain the flexible substrate.

[0029] The present invention provides an adjustable absorber, which is a non-volatile perfect absorber designed by using phase change materials. The absorber is a multilayer thin film structure composed of phase change materials, easily available metals and dielectric materials. This structure can be combined with flexible substrates or rigid substrates. It is a few-layer perfect absorber that does not require photolithography and has a simple process. By utilizing the few-layer heterostructure and strong interference effect, it can achieve high absorption rate in a wide frequency range. It has potential scalability and cost-effectiveness, and is of great significance for the manufacture of efficient absorbers. The phase change material accumulates heat through electrodes under different pulse conditions, has a changeable phase structure, and has different colors in different phases. The phase change of the phase change absorber can be changed by annealing, laser, and conductive electrodes, thereby realizing the regulation of light. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 It is a structural schematic diagram of an adjustable absorber provided by the present invention;

[0032] Figure 2 This is a schematic diagram of the absorption rate simulation of the entire device when GSST and GST are in different states in an adjustable absorber provided by the present invention;

[0033] Figure 3 This is a schematic diagram of the change in reflectivity of GSST and GST in an adjustable absorber provided by the present invention when they are in an amorphous state as the angle changes;

[0034] Figure 4 This is a schematic diagram of the change in reflectivity of an adjustable absorber provided by the present invention when GSST is in an amorphous state and in a crystalline state as the angle changes;

[0035] Figure 5 This is a schematic diagram of the change in reflectivity with angle change when GSST is in a crystalline state and GST is in an amorphous state in an adjustable absorber provided by the present invention;

[0036] Figure 6 It is a schematic diagram of a tunable absorber provided by the present invention in which GSST is in a crystalline state and the reflectivity changes with angle when GST is in the crystalline state;

[0037] Figure 7 It is a schematic diagram of experimental data and simulation comparison of angle variation and absorption when both GSST and GST are in amorphous state in an adjustable absorber provided by the present invention;

[0038] Figure 8 It is a schematic diagram of experimental data and simulation comparison of angle change and absorption when both GSST and GST are in a crystalline state in an adjustable absorber provided by the present invention;

[0039] Figure 9 This is a curve distribution diagram showing the effect of the change in MgF2 thickness on the absorption of the overall structure in an adjustable absorber provided by the present invention;

[0040] Figure 10 This is a schematic diagram of the curve distribution of the effect of the thickness of the silicon oxide third dielectric layer on the absorption of the overall structure in an adjustable absorber provided by the present invention;

[0041] Figure 11 This is a schematic diagram of the curve distribution of the effect of the thickness of the silicon oxide first dielectric layer on the absorption of the entire structure in an adjustable absorber provided by the present invention;

[0042] Figure 12 This is a schematic diagram of the curve distribution of the effect of the thickness of the silicon oxide second dielectric layer on the absorption of the overall structure in an adjustable absorber provided by the present invention;

[0043] Figure 13 It is a schematic diagram of the curve distribution of the influence of the thickness of the first phase change layer and the second phase change layer on the absorption of the overall structure in an adjustable absorber provided by the present invention.

[0044] Reference numerals:

[0045] 1: anti-reflection layer; 2: third dielectric layer; 3: second phase change layer; 4: second dielectric layer; 5: first phase change layer; 6: first dielectric layer; 7: metal layer; 8: substrate. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0047] The following combination Figure 1 The present invention describes a tunable absorber comprising:

[0048] From bottom to top, there are arranged in sequence: a substrate 8, a metal layer 7, a first dielectric layer 6, a first phase change layer 5, a second dielectric layer 4, a second phase change layer 3, a third dielectric layer 2 and an anti-reflection layer 1;

[0049] The substrate 8 is a flexible substrate or a rigid substrate, and the material of the flexible substrate can be PET, PEN, PDMS or PC;

[0050] The phase change material in the first phase change layer 5 and the phase change material in the second phase change layer 3 undergo a transition between a crystalline state and an amorphous state under the stimulation of a thermal field, an electric field or a laser pulse, resulting in a phase change. The light is controlled by the changes in the refractive index and the extinction coefficient before and after the phase change.

[0051] The phase change material can be transformed between the amorphous state and the crystalline state by irradiating a laser or performing a high-temperature annealing treatment, or the crystallization state of the phase change material can be controlled by applying a voltage to the electrodes. Specifically, a long and medium-intensity voltage or laser pulse is applied to the phase change material, and the temperature of the phase change material is raised to a temperature range above the crystallization temperature and below the melting temperature, and maintained for a set time. At this time, the lattice is orderly arranged to form a crystalline state, realizing the transformation from the amorphous state to the crystalline state; a short and strong voltage or laser pulse is applied to the phase change material, so that the temperature of the phase change material is raised to above the melting temperature, so that the long-range order of the crystalline state is destroyed. The pulse falling edge is very short, causing the phase change material to be rapidly cooled to below the crystallization temperature, so that the phase change material is fixed in the amorphous state, realizing the transformation from the crystalline state to the amorphous state. The transmittance change of the phase change material of the first phase change layer 5 and the second phase change layer 3 when transforming between the amorphous state and the crystalline state is used to absorb light in the wavelength range of 300nm to 1600nm, thereby realizing black and white display.

[0052] In addition, the mutual transformation between the amorphous state and the crystalline state is not limited to the heating induced by applying current pulses, but any other electromagnetic field-induced heating can also be used. The structure measured from the experiment is in good agreement with the simulation results. Electrical stimulation can also be used, such as 20% crystallization, 40% crystallization, etc. to obtain a mixed phase. Partial crystallization can be simply achieved by limiting the maximum current or laser power during the conversion process. The reflectivity and light absorption of the material between completely amorphous and completely crystalline depends on the degree of partial crystallization. Multiple states can be obtained through electrical stimulation, making the structure dynamically adjustable.

[0053] Phase change materials have different refractive indices and extinction coefficients when transforming between amorphous and crystalline states. Different voltage pulses or thermal excitations are applied to them to achieve light absorption modulation, which can achieve more than 90% absorption of light in the wavelength range of 400nm to 900nm, and dynamic regulation of light in the range of 300nm to 3000nm; the absorption rate can reach more than 99.7% between the wavelength of 400nm to 850nm, and more than 90% between 300nm and 1000nm. It has high light absorption efficiency, fast response speed and can be dynamically tunable, with the maximum tuning position reaching more than 30%.

[0054] The phase change layer has at least two layers. Dielectric materials such as SiO2, TiO2 and MgF2 are deposited on the top phase change layer to form a stacked structure with a gradient refractive index distribution, which produces an anti-reflection effect. The high absorption material (i.e., phase change material) is responsible for producing strong absorption at wavelengths of 300nm to 3000nm.

[0055] The phase change materials in the first phase change layer 5 and the second phase change layer 3 may include the following chalcogenides and their alloys, including but not limited to: GeTe, SbTe, BiTe, InSb, InSe, GeSb, SbSe, GaSb, GaSb, GeSbTe, AgInSbTe, InSbTe, AgSbTe, Ag2In4Sb 76 Te 17 (AIST). In addition, the atomic percentages in the above chemical formulas may vary. The first phase change layer 5 and the second phase change layer 3 may further contain at least one dopant, such as C or N.

[0056] Optionally, the phase change material of the phase change layer is GeTe, SbTe, BiTe, InSb, InSe, GeSb, SbSe, GaSb, GaSb, GeSbTe, AgInSbTe, InSbTe or AgSbTe, and the thickness of the phase change layer is less than 100 nm.

[0057] The phase change material can be GST or GSST. Under the same thickness, the refractive index and extinction coefficient of GST and GSST before and after the phase change change greatly. In addition, the phase change state of the phase change materials GST and GSST is stable and easy to operate electrically.

[0058] Optionally, the thickness of the first dielectric layer 6 between the metal layer 7 and the first phase change layer 5 , and the second dielectric layer 4 between the first phase change layer 5 and the second phase change layer 3 is 5 nm to 500 nm.

[0059] The metal layer 7 is mainly used to generate thermal excitation and act as a mirror. Under electrical excitation, it generates sufficient heat so that the reflectivity and extinction coefficient of the phase change material of the first phase change layer 5 and the phase change material of the second phase change layer 3 change when they transform between the amorphous state and the crystalline state, thereby realizing the regulation of light and then achieving the black state.

[0060] A nonvolatile perfect absorber designed with phase-change materials utilizes the FP resonant cavity and the high K value of the phase-change material to achieve light absorption and dissipation. Heat accumulation within the bottom electrode metal layer 7 of the multilayer thin-film stack causes the phase-change material to change state, thereby absorbing light. As the phase-change material transitions between crystalline and amorphous states, its refractive index n and extinction coefficient k also change.

[0061] Multilayer thin-film phase-change absorbers can be deposited on flexible substrates such as PET, PEN, PDMS, and PC to create flexible display devices, improving their flexibility and durability while reducing the probability of accidental damage. They can also be applied to wearable devices, enhancing their comfort.

[0062] The main functions of the first dielectric layer 6 and the second dielectric layer 4 are to isolate the phase change material and to form a resonant cavity with the phase change material. The third dielectric layer 2 and the anti-reflection layer 1 act as a refractive index matching layer between the air and the rest of the structure. The refractive index matching layer on the top reduces the reflection and intensity of the main light beam of the phase change material at the interface. And to achieve wide angle sensitivity, it is calculated through the phase balance equation of the FP cavity that the overall phase satisfies a certain optical system to achieve no reflection on the top surface. This is mainly attributed to the reflection cancellation caused by the accumulated phase of the partial light beam when it propagates back and forth in the cavity. In this way, complete destructive interference can be easily achieved. At the same time, the GSST and GST films are protected from oxidation.

[0063] The absorption mechanism of the entire device can be attributed to strong absorption in the ultrathin semiconductor layer and interference between multiple reflected beams. In this case, due to the high refractive index of the phase change material at these wavelengths, the beam accumulates a strong phase difference after passing through the phase change layer and reflecting from the metal mirror. If the relative phase difference is equal to π, part of the beam will destructively interfere with the main beam reflected from the top surface of the phase change layer. It is worth noting that a phase difference of π is not the only condition for achieving zero reflection in the device. The sum of the amplitudes of the reflected beams must be close to that of the main beam. At the same time, the top matching layer reduces the reflection and intensity of the main beam at the phase change material interface. In this way, complete destructive interference can be easily achieved.

[0064] Furthermore, the absorption remains high at larger angles of incidence. This is due to the fact that the structure consists of very thin layers and, due to the high refractive index and high extinction coefficient of the phase-change material, the internal angle of the refracted beam is very small, so a large angle is required to stay away from destructive interference conditions.

[0065] This embodiment uses phase change materials to design a non-volatile perfect absorber, which is a multilayer thin film structure composed of phase change materials, easily available metals and dielectric materials. This structure can be combined with flexible substrates or rigid substrates. It is a few-layer perfect absorber that does not require lithography and has a simple process. By utilizing the few-layer heterostructure and strong interference effect, it can achieve high absorption rate over a wide frequency range. It has potential scalability and cost-effectiveness, which is of great significance for the manufacture of efficient absorbers. The phase change material accumulates heat through electrodes under different pulse conditions and has a changeable phase structure. It has different colors in different phases. The phase change of the phase change absorber can be changed through annealing, laser, and conductive electrodes, thereby realizing the regulation of light.

[0066] Based on the above embodiment, in this embodiment, the thickness of the first phase change layer 5 and the second phase change layer 3 are respectively in the range of 3 nm to 100 nm;

[0067] The thickness of the anti-reflection layer 1 ranges from 0 nm to 500 nm, and the refractive index of the anti-reflection layer 1 is greater than the refractive index of the third dielectric layer;

[0068] The K value of the first dielectric layer 6 , the second dielectric layer 4 , the third dielectric layer 2 and the anti-reflection layer 1 is less than 1.

[0069] On the basis of the above embodiment, in this embodiment, the first phase change layer 5 and the second phase change layer 3 have different phase change thresholds.

[0070] Based on the above embodiment, the phase change material of the first phase change layer 5 in this embodiment is an alloy compound composed of a Group VI element and Group III to Group V elements and doped with a Group Ib element;

[0071] The phase change material of the second phase change layer 3 is an alloy compound composed of a Group VI element and elements of Groups III to V and doped with a Group Ib element.

[0072] Based on the above embodiment, the phase change material of the first phase change layer 5 in this embodiment includes one or more of GeTe, SbTe, BiTe, InSb, InSe, GeSb, SbSe, GaSb, GeSbTe, AgInSbTe, InSbTe, AgSbTe, SiTe, SnTe, and SnSb; wherein the atomic percentage of each phase change material is adjustable;

[0073] The phase change material of the second phase change layer 3 includes one or more of GeTe, SbTe, BiTe, InSb, InSe, GeSb, SbSe, GaSb, GeSbTe, AgInSbTe, InSbTe, AgSbTe, SiTe, SnTe, and SnSb; wherein the atomic percentage of each phase change material is adjustable.

[0074] Based on the above embodiments, the metal layer 7 in this embodiment is a single substance formed by one of the elements of the III to V main groups such as Ag, Al, Au, Cu or Pt, or a compound composed of multiple elements in any proportion. The thickness of the single-layer metal layer 7 is greater than 100 nm, and the metal layer 7 is used to generate thermal excitation and mirror reflection.

[0075] On the basis of the above embodiments, in this embodiment, the metal layer 7 is ITO, Ag, Au or W, and the thickness of the metal layer 7 is greater than 50 nm.

[0076] On the basis of the above embodiments, the anti-reflection layer 1 in this embodiment is one or more of SiO2, TiO2, MgF2, Si3N4, ITO and AlN, and the thickness of the anti-reflection layer 1 is 5nm to 500nm.

[0077] The anti-reflection layer 1 is a coating applied on an optical surface and is designed with a refractive index gradient to reduce reflection and increase transmittance. Its thickness varies between 10 nm and 500 nm.

[0078] Commonly used anti-reflection layer materials include silicon dioxide (SiO2), one of the most commonly used anti-reflection layer materials, suitable for visible light and near-infrared spectral ranges; titanium dioxide (TiO2), also a commonly used anti-reflection layer material, suitable for visible light and ultraviolet spectral ranges; magnesium fluoride (MgF2), suitable for the ultraviolet spectral range, has a low refractive index; indium tin oxide (ITO), commonly used in transparent conductive films, and has certain anti-reflection properties; silicon nitride (Si3N4), suitable for high temperature and optical applications, has high durability and chemical stability; aluminum nitride (AlN), suitable for the ultraviolet spectral range, has good heat resistance and mechanical strength. In addition to the above materials, there are other special materials and multilayer structures that can be used to customize anti-reflection layers for specific wavelength ranges. Not limited to the above materials, other functional layers with specific anti-reflection effects on light are also suitable.

[0079] The coating material of the anti-reflection layer 1 is a dielectric material such as ZnO, ZnS or TiO2, and has a refractive index gradient from high to low, with a thickness of 10 nm to 500 nm.

[0080] Based on the above embodiment, in this embodiment, the first dielectric layer 6 is one or more of SiO2, HfO, Al2O3, ZnO, In2O3, TiO2, Si3N4 and MgF2, and the thickness of the first dielectric layer 6 is 1 nm to 500 nm;

[0081] The second dielectric layer 4 is one or more of SiO2, HfO, Al2O3, ZnO, In2O3, TiO2, Si3N4 and MgF2, and the thickness of the second dielectric layer 4 is 1 nm to 500 nm;

[0082] The third dielectric layer 2 is one or more of SiO2, HfO, Al2O3, ZnO, In2O3, TiO2, Si3N4 and MgF2, the thickness of the third dielectric layer 2 is 1nm to 500nm, and the n value of the third dielectric layer 2 is less than the n value of the anti-reflection layer.

[0083] Based on the above embodiments, the manufacturing steps of the flexible substrate in this embodiment include:

[0084] Use a spin coater to evenly coat PDMS (Polydimethylsiloxane) on a rigid silicon substrate.

[0085] After uniform coating, the film was solidified by passing through a multi-gradient temperature annealing furnace, wherein the temperature gradient was set to 100°C for 10 min, 150°C for 10 min, 200°C for 10 min, 250°C for 10 min, 300°C for 10 min, 350°C for 10 min, 350°C for 10 min, and 400°C for 10 min, and then cooled at a cooling rate of 1°C / min to obtain a flexible thin film PDMS;

[0086] The flexible thin film PDMS is cleaned by a plasma cleaning machine to obtain the flexible substrate.

[0087] By optimizing the structural parameters of the absorber, it can be obtained that the metal layer 7 is W (thickness 200nm), the first dielectric layer 6 is SiO2 (thickness 16nm), the first phase change layer 5 is GST (thickness 6nm), the second dielectric layer 4 is TiO2 (thickness 11nm), the second phase change layer 3 is GSST (thickness 6nm), the third dielectric layer 2 is SIO2 (thickness 55nm), and the anti-reflection layer 1 is MgF2 (thickness 22nm). This allows the structure to absorb more than 99% of light in the range of 300nm to 1000nm, and can be dynamically adjusted from 0 to 30% in the range of 300nm to 1600nm.

[0088] Figures 2 to 6 It is a spectrum diagram of the absorption rate and angle change of the phase change absorber when the phase change materials GeSbSeTe and GeSbTe are in different states, showing the transmission spectrum of the RGB primary colors.

[0089] Figure 2 Figure 2 shows the simulated absorption rate of the entire device when GSST and GST are in different states, as well as the n and k values of each material layer. It can be seen that the N value of the anti-reflection layer MgF2 is greater than that of SiO2.

[0090] Figure 3 This is a graph showing the change in reflectivity of GSST and GST with angle changes when they are in the amorphous state. It can be seen that S and P polarized light are not sensitive to changes in angle.

[0091] Figure 4 The graph shows the change of reflectivity with angle when GSST is in amorphous state and crystalline state. It can be seen that S and P polarized light are not sensitive to angle changes.

[0092] Figure 5 The graph shows the change of reflectivity with angle when GSST is in crystalline state and GST is in amorphous state. It can be seen that S and P polarized light are not sensitive to angle changes.

[0093] Figure 6This is a graph showing the change in reflectivity with angle when GSST is in the crystalline state. It can be seen that S and P polarized light are insensitive to angle changes.

[0094] From the simulation, it can be seen that this structure is insensitive to angle changes. Annealing is used to make the phase change material in different states.

[0095] Figure 7 The experimental data and simulation comparison of the angle change and absorption for the phase change materials GSST and GST in the amorphous state show that the experimental data closely matches the simulation trends, with slight differences due to inaccurate film thickness.

[0096] Figure 8 The experimental data and simulation comparison chart of angle change and absorption when the phase change materials GSST and GST are both in the crystalline state. It can be seen that the experiment is in line with the simulation trend very well. The slight difference is caused by inaccurate film thickness.

[0097] Figure 9 FIG. 4 is a curve distribution diagram showing the effect of the change in MgF 2 thickness on the absorption of the overall structure. It can be seen that the optimal thickness of the anti-reflection layer 1 is 5 nm to 100 nm.

[0098] Figure 10 FIG. 2 is a curve distribution diagram showing the effect of the thickness of the silicon oxide in the third dielectric layer 2 on the absorption of the entire structure. It can be seen that the optimal thickness of the third dielectric layer 2 is 5 nm to 125 nm.

[0099] Figure 11 FIG. 4 is a curve distribution diagram showing the effect of the thickness of the silicon oxide in the first dielectric layer 6 on the absorption of the entire structure. It can be seen that the optimal thickness of the first dielectric layer 6 is 1 nm to 50 nm.

[0100] Figure 12 FIG. 4 is a curve distribution diagram showing the effect of the thickness of the silicon oxide in the second dielectric layer 4 on the absorption of the entire structure. It can be seen that the optimal thickness of the second dielectric layer 4 is 1 nm to 50 nm.

[0101] Figure 13 3 is a curve distribution diagram showing the effect of the thickness of the first phase change layer 5 and the second phase change layer 3 on the absorption of the overall structure. It can be seen that the optimal thickness of the two layers is 2 nm to 8 nm.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An adjustable absorber, characterized in that: include: A substrate, a metal layer, a first dielectric layer, a first phase change layer, a second dielectric layer, a second phase change layer, a third dielectric layer, and an anti-reflection layer are sequentially arranged from bottom to top, wherein the refractive index of the anti-reflection layer is greater than the refractive index of the third dielectric layer, the thickness of the anti-reflection layer ranges from 0 nm to 500 nm, the K value of the anti-reflection layer is less than 1, and the third dielectric layer and the anti-reflection layer form a stacked structure with a gradient refractive index distribution to produce an anti-reflection effect; The substrate is a flexible substrate or a rigid substrate; The phase change material in the first phase change layer and the phase change material in the second phase change layer undergo a transition between a crystalline state and an amorphous state under the stimulation of a thermal field, an electric field or a laser pulse, resulting in a phase change, and light is controlled by the changes in the refractive index and the extinction coefficient before and after the phase change; The metal layer generates sufficient heat under electrical excitation, so that the reflectivity and extinction coefficient of the phase change material of the first phase change layer and the phase change material of the second phase change layer change when they mutually transform between the amorphous state and the crystalline state, thereby achieving light regulation and further achieving a black state; The thickness of the first phase change layer and the second phase change layer are respectively in the range of 3 nm to 100 nm; The phase change material of the first phase change layer includes one or more of GeTe, SbTe, BiTe, InSb, InSe, GeSb, SbSe, GaSb, GeSbTe, AgInSbTe, InSbTe, AgSbTe, SiTe, SnTe and SnSb; wherein the atomic percentage of each phase change material is adjustable; The phase change material of the second phase change layer includes one or more of GeTe, SbTe, BiTe, InSb, InSe, GeSb, SbSe, GaSb, GeSbTe, AgInSbTe, InSbTe, AgSbTe, SiTe, SnTe and SnSb; wherein the atomic percentage of each phase change material is adjustable; The K values of the first dielectric layer, the second dielectric layer, and the third dielectric layer are less than 1.

2. The adjustable absorber according to claim 1, characterized in that The first phase change layer and the second phase change layer have different phase change thresholds.

3. The adjustable absorber according to claim 1, characterized in that The phase change material of the first phase change layer is an alloy compound composed of a VI main group element and a III to V main group element and doped with an Ib main group element; The phase change material of the second phase change layer is an alloy compound composed of a VI main group element and elements of groups III to V and doped with an Ib main group element.

4. The adjustable absorber according to claim 1, characterized in that The metal layer is a simple substance formed by one of the elements of the main groups III to V or a compound composed of multiple elements in any proportion.

5. The adjustable absorber according to claim 4, characterized in that The metal layer is ITO, Ag, Au or W, and the thickness of the metal layer is greater than 50 nm.

6. The adjustable absorber according to claim 1, characterized in that The anti-reflection layer is one or more of SiO2, TiO2, MgF2, Si3N4, ITO and AlN, and the thickness of the anti-reflection layer is 5nm to 500nm.

7. The adjustable absorber according to claim 1, characterized in that The first dielectric layer is one or more of SiO2, HfO, Al2O3, ZnO, In2O3, TiO2, Si3N4 and MgF2, and the thickness of the first dielectric layer is 1 nm to 500 nm; The second dielectric layer is one or more of SiO2, HfO, Al2O3, ZnO, In2O3, TiO2, Si3N4 and MgF2, and the thickness of the second dielectric layer is 1 nm to 500 nm; The third dielectric layer is one or more of SiO2, HfO, Al2O3, ZnO, In2O3, TiO2, Si3N4 and MgF2, the thickness of the third dielectric layer is 1nm to 500nm, and the n value of the third dielectric layer is less than the n value of the anti-reflection layer.

8. The adjustable absorber according to any one of claims 1 to 7, characterized in that: The manufacturing steps of the flexible substrate include: Use a coating machine to evenly coat the PDMS spin coating liquid on the rigid silicon substrate; After uniform coating, the film was solidified by passing through a multi-gradient temperature annealing furnace, wherein the temperature gradient was set to 100°C for 10 min, 150°C for 10 min, 200°C for 10 min, 250°C for 10 min, 300°C for 10 min, 350°C for 10 min, 350°C for 10 min, and 400°C for 10 min, and then cooled at a cooling rate of 1°C / min to obtain a flexible thin film PDMS; The flexible thin film PDMS is cleaned by a plasma cleaning machine to obtain the flexible substrate.

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