Narrowband absorption devices based on phase change materials

Abstract

The present invention provides a narrowband absorption device based on phase change material, the device comprises: a narrowband absorption cavity structure, including a metal layer, a dielectric layer and a phase change layer; a lithium tantalate single crystal structure, located under the narrowband absorption cavity structure; when light is incident on the narrowband absorption cavity structure, the narrowband absorption cavity structure is used to absorb light of corresponding wavelength to generate a pyroelectric effect, and the lithium tantalate single crystal structure is used to generate current to obtain the light intensity information of the light according to the magnitude of the current, and change the state of the phase change layer according to the magnitude of the current to control the switching of the light. The present invention can monitor the intensity of light and realize dynamic switch regulation, and has a very narrow half-height width, is insensitive to angles, has a simple structure, is easy to integrate, and has a high switching ratio.

Description

Technical Field

[0001] The present invention relates to the technical field of phase change materials, and in particular to a narrow-band absorption device based on phase change materials. Background Art

[0002] In recent years, many different types of plasma refractive index sensors operating in the infrared and terahertz bands have emerged, including hybrid microcavities, nanodisks, network-type metasurfaces, metal gratings, or narrow-band absorption structures composed of other media and metal structures. However, the manufacture of these devices requires expensive and difficult-to-scale fine nanofabrication technology, lacks flexibility in design, and faces the problem that once the device is formed, the absorption band cannot be dynamically adjusted, which also makes the device structure complicated and it is impossible to use a single device for multi-band regulation.

[0003] In the existing narrow-band absorber structure, the narrow-band absorber structure mainly adopts the metal / dielectric / metal structure, the structure of metal and dielectric combination, or the form of metasurface composed of dielectric / metal, which is complex and sensitive to angle changes. Most metal / dielectric / metal structures are easily affected by the structure, that is, their color changes with the change of polarization and incident angle. Or the structure composed of metal and dielectric combination cannot realize dynamic switching combination and detect the intensity of light. Therefore, it is of great practical significance to design a narrow-band absorption technology that is both dynamically adjustable. Summary of the invention

[0004] The present invention provides a narrowband absorption device based on phase change material, which is used to solve the defect that the narrowband absorption device in the prior art cannot realize dynamic regulation, and realize the dynamic regulation of the narrowband absorption device.

[0005] The present invention provides a narrowband absorption device based on phase change material, comprising:

[0006] A narrowband absorption cavity structure, comprising a metal layer, a dielectric layer and a phase change layer;

[0007] A lithium tantalate single crystal structure, located below the narrow-band absorption cavity structure;

[0008] When light hits the narrowband absorption cavity structure, the narrowband absorption cavity structure is used to absorb light of corresponding wavelength to produce a pyroelectric effect, and the lithium tantalate single crystal structure is used to generate current to obtain the light intensity information of the light according to the magnitude of the current, and change the state of the phase change layer according to the magnitude of the current to control the switching of the light.

[0009] According to a narrowband absorption device based on phase change material provided by the present invention, the narrowband light absorber cavity structure includes a first metal layer, a first dielectric layer, a phase change layer, a second dielectric layer, a second metal layer and a third dielectric layer arranged in sequence from bottom to top.

[0010] According to a narrowband absorption device based on phase change material provided by the present invention, the voltage applied to the first metal layer is regulated according to the magnitude of the current, and the crystallization and amorphization ratio of the phase change material in the phase change layer is controlled to regulate the absorption of the light.

[0011] According to a phase change material-based narrowband absorption device provided by the present invention, the phase change material used in the phase change layer has an optical loss greater than a first preset threshold value, and a refractive index less than a second preset threshold value;

[0012] The reflectivity of the metal layer is greater than a third preset threshold.

[0013] According to a phase change material based narrowband absorption device provided by the present invention, the thickness of the phase change material used in the phase change layer is less than 1 micron.

[0014] According to a phase change material based narrowband absorption device provided by the present invention, there are a plurality of phase change layers, and each phase change layer includes a phase change material layer and electrode layers located on both sides of the phase change material layer.

[0015] According to a narrow-band absorption device based on phase change material provided by the present invention, the electrode layer between two adjacent phase change material layers is shared.

[0016] According to a phase change material-based narrowband absorption device provided by the present invention, a reflective layer is further included between the first metal layer and the first dielectric layer.

[0017] According to a narrowband absorption device based on phase change material provided by the present invention, the first metal layer is W, the reflective layer is Ag, and the first dielectric layer is TIO 2 , the phase change layer is GSST, and the second dielectric layer is TIO 2 The second metal layer is Ag, and the third dielectric layer is MgF 2 .

[0018] According to a narrowband absorption device based on phase change material provided by the present invention, the thickness of the first metal layer is 200nm, the thickness of the reflective layer is 200nm, the thickness of the first dielectric layer is 78nm, the thickness of the phase change layer is 100nm, the thickness of the second dielectric layer is 78nm, the thickness of the second metal layer is 22nm, the thickness of the third dielectric layer is 22nm, and the thickness of the lithium tantalate single crystal structure is 75 microns.

[0019] The narrow-band absorption device of the phase change material provided by the present invention absorbs the corresponding wavelength through the narrow-band absorption cavity structure. Due to the pyroelectric effect, the lithium tantalate single crystal structure can generate current, and the light intensity information can be obtained according to the current size to monitor the light intensity; and the state of the phase change layer is changed according to the current size, so as to adjust the proportion of target light absorption and realize dynamic switching control. The half-width is very narrow, insensitive to angles, simple in structure, easy to integrate, and high in switching ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces 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 creative work.

[0021] Figure 1 is a schematic structural diagram of a narrow-band absorption device based on phase change material provided by the present invention;

[0022] Figure 2 It is a schematic diagram of the absorption spectrum of the narrow-band absorption device based on phase change material provided by the present invention;

[0023] Figure 3 The present invention provides a schematic diagram of a curve showing the change of current detected by a narrow-band absorption device based on phase change material over time.

[0024] Reference numerals:

[0025] 101: first metal layer; 102: reflective layer; 103: first dielectric layer; 104: phase change layer; 105: second dielectric layer; 106: second metal layer; 107: third dielectric layer; 108: lithium tantalate single crystal structure. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Combine the following Figure 1 The invention discloses a narrowband absorption device based on phase change material, comprising:

[0028] A narrowband absorption cavity structure, comprising a metal layer, a dielectric layer and a phase change layer;

[0029] A lithium tantalate single crystal structure 108, located below the narrow-band absorption cavity structure;

[0030] When light hits the narrowband absorption cavity structure, the narrowband absorption cavity structure is used to absorb light of corresponding wavelength to produce a pyroelectric effect, and the lithium tantalate single crystal structure is used to generate current to obtain the light intensity information of the light according to the magnitude of the current, and change the state of the phase change layer according to the magnitude of the current to control the switching of the light.

[0031] This embodiment does not limit the number and arrangement order of metal layers, dielectric layers and phase change layers. Optionally, multiple metal layers are located on both sides of the phase change layer, and multiple dielectric layers are located on both sides of the phase change layer to form a FP (Fabry-perot, resonant cavity) cavity structure.

[0032] The phase change layer includes a phase change material, and the metal layers on both sides of the phase change material play the role of forming an FP cavity with the phase change material and controlling the phase change of the phase change material. By applying voltage to the metal layers on both sides of the phase change material, the crystal structure of the phase change material can be changed, thereby adjusting the absorption peak and position of the narrow-band absorber structure.

[0033] When the narrowband absorption cavity structure is combined with the lithium tantalate single crystal structure 108, light is irradiated to the narrowband absorption cavity structure, and the corresponding wavelength is absorbed. Due to the pyroelectric effect, the lithium tantalate single crystal structure can generate current, and the light intensity information is obtained according to the current. At the same time, the state of the phase change material can be changed according to the current to achieve the effect of switching on and off, and the switch can be controlled to be turned off according to actual needs.

[0034] The magnitude of the output current of the lithium tantalate single crystal structure 108 can be used as a reference for the regulation of the phase change material. The magnitude of the output current of the lithium tantalate single crystal structure 108 can be compared with the magnitude of the current required for the switch to be turned off, and the voltage or pulse current applied to the phase change material can be adjusted according to the comparison result, so that the magnitude of the output current of the lithium tantalate single crystal structure 108 is consistent with the magnitude of the current required for the switch to be turned off.

[0035] Through this design, the narrow-band absorption structure can be adjusted according to actual needs and the proportion of target light absorption can be adjusted, with a high switching ratio of more than 90%. It can also be made insensitive to angles to meet the needs of narrow-band absorbers for sensors and monochromatic light detectors.

[0036] This embodiment absorbs the corresponding wavelength through a narrow-band absorption cavity structure. Due to the pyroelectric effect, the lithium tantalate single crystal structure can generate current, and the light intensity information can be obtained according to the current size to monitor the light intensity; and the state of the phase change layer is changed according to the current size, so as to adjust the proportion of target light absorption and realize dynamic switching control. The half-width is very narrow, insensitive to angles, simple in structure, easy to integrate, and has a high switching ratio.

[0037] On the basis of the above embodiments, the narrow-band light absorber cavity structure in this embodiment includes a first metal layer 101, a first dielectric layer 103, a phase change layer 104, a second dielectric layer 105, a second metal layer 106 and a third dielectric layer 107 arranged sequentially from bottom to top.

[0038] The narrowband light absorber cavity structure is composed of a dielectric-metal-dielectric-phase change material-dielectric-metal (MDM) cavity or a plurality of cavities of the same type, wherein the third dielectric layer 107 at the top is a lossless material covering layer.

[0039] On the basis of the above embodiment, in this embodiment, the voltage applied to the first metal layer is regulated according to the magnitude of the current to control the crystallization and amorphization ratio of the phase change material in the phase change layer to regulate the absorption of the light.

[0040] The phase change material of the phase change layer 104 can be converted between a crystalline state and an amorphous state under electrical stimulation or laser stimulation, thereby changing the transmittance and reflectivity of the phase change layer. A transparent lossless material MgF 2 The phase change layer 104 can control the crystallization state of the phase change material by applying a voltage on the first metal layer 101W.

[0041] Specifically, when a pulse voltage of medium intensity is applied to W, W will generate heat. Under the action of heat, the temperature of the phase change material rises to a temperature range above the crystallization temperature and below the melting temperature, and is maintained for a certain period of time. At this time, the lattice is orderly arranged to form a crystalline state, realizing the transformation from amorphous to crystalline.

[0042] A short and strong voltage is applied to W, which generates high heat in an instant, causing the temperature of the phase change material to rise above the melting temperature, destroying the long-range order of the crystalline state. The pulse falling edge is very short, causing the phase change material to be quickly cooled to below the crystallization temperature, fixing the phase change material in the amorphous state, and realizing the transition from crystalline to amorphous state.

[0043] The ratio of light absorption by the narrow-band absorption cavity structure is regulated by the changes in transmittance and reflectivity of the phase change material of the phase change layer 104 when the phase change material transforms between the amorphous state and the crystalline state.

[0044] The phase change material of the phase change layer 104 may include the following chalcogenides and their alloys, including but not limited to GST, GSST, IST, GeSbTe, AgInSbTe, InSbTe, AgSbTe, Ag 2 In 4 Sb 76 Te 17 (AIST) and other high-loss and low-refractive-index characteristic phase change materials. In addition, the atomic percentages in the above chemical formulas can be varied. The phase change material layer can further include at least one dopant, such as C and N. Preferably, the phase change material is GSST, which has high loss in the visible light range and low refractive index, and GSST has good thermal stability.

[0045] The phase change layer of the phase change narrow-band absorption cavity structure has very different absorption of light in different states. The phase change material is stable in the crystalline and amorphous states, so the voltage or laser can be removed when the phase change material is in a stable state. The power consumption of the entire detection device during the detection process is very low and is dynamically adjustable.

[0046] Based on the above embodiment, the phase change material used in the phase change layer in this embodiment has an optical loss greater than a first preset threshold value, and a refractive index less than a second preset threshold value;

[0047] The reflectivity of the metal layer is greater than a third preset threshold.

[0048] The phase change material of the narrowband absorber cavity structure can be GSST, and the metal can be Ag. GSST is an ultra-thin phase change material with strong optical loss, and Ag is a high reflectivity material metal. The phase change material in the narrowband absorber cavity is high loss and low refractive index, including but not limited to GSST, and materials with this characteristic formed by doping.

[0049] The narrowband absorption cavity structure is composed of high-loss and low-refractive-index phase-change materials and metal materials. An ultra-thin phase-change material film with strong optical loss and low refractive index is deposited on a highly reflective metal substrate.

[0050] A lithium tantalate single crystal is bonded to the bottom of the structure. The selectively absorbed light will be converted into heat energy and transmitted to the pyroelectric material. The pyroelectric material converts heat energy into electrical energy through the pyroelectric effect. Therefore, the intensity of the light signal can be detected according to the magnitude of the current, and the voltage applied to the metal driving the phase change material can be adjusted to control the crystallization and amorphization ratio of the phase change material to control the absorption of light. Compared with the traditional narrow-band absorption structure, this design can monitor the intensity of the target light and realize dynamic switch control. It has a simple structure and is easy to integrate.

[0051] Based on the above embodiment, the thickness of the phase change material used in the phase change layer 104 in this embodiment is less than 1 micron.

[0052] The thickness of the phase change material used in the phase change layer 104 is less than 1 micron. Since the increase in the thickness of the phase change material will increase the temperature required for the crystallization of the phase change material, the more suitable thickness is within 1 micron. The phase change material of the phase change layer 104 can be driven by voltage. When driven by voltage, the metal W at the bottom of the narrow-band absorption cavity structure applies voltage to cause the phase change material to undergo phase change.

[0053] On the basis of the above embodiment, in this embodiment, there are a plurality of phase change layers 104 , and each phase change layer 104 includes a phase change material layer and electrode layers located on both sides of the phase change material layer.

[0054] On the basis of the above embodiment, in this embodiment, the electrode layer between two adjacent phase change material layers is shared.

[0055] Based on the above embodiments, Figure 1 As shown, in this embodiment, a reflective layer 102 is further included between the first metal layer 101 and the first dielectric layer 103 .

[0056] Based on the above embodiment, in this embodiment, the first metal layer 101 is W, the reflective layer 102 is Ag, and the first dielectric layer 103 is TiO. 2 The phase change layer 104 is GSST, and the second dielectric layer 105 is TIO 2 The second metal layer 106 is Ag, and the third dielectric layer 107 is MgF 2 .

[0057] On the basis of the above embodiments, in this embodiment, the thickness of the first metal layer 101 is 200nm, the thickness of the reflective layer 102 is 200nm, the thickness of the first dielectric layer 103 is 78nm, the thickness of the phase change layer 104 is 100nm, the thickness of the second dielectric layer 105 is 78nm, the thickness of the second metal layer 106 is 22nm, the thickness of the third dielectric layer 107 is 22nm, and the thickness of the lithium tantalate single crystal structure 108 is 75 microns.

[0058] like Figure 2 As shown, by applying different voltages, the phase change material layer changes from amorphous to partially crystallized to fully crystallized. The magnitude of the applied voltage depends on the magnitude of the output current of the lithium tantalate single crystal wafer, and corresponding negative feedback is performed until the absorption effect reaches the target effect. The absorption ratio of the target light is adjusted according to actual needs.

[0059] This embodiment provides an absorption structure composed of a narrow-band absorber structure and a detector based on a lithium tantalate single crystal. The two together form a tunable narrow-band absorption structure based on phase change materials, which can solve the problem that the absorption structures based on metasurfaces, gratings, etc. cannot always adjust the proportion of light absorbed in the target band, and the narrow band is sensitive to angle changes and has a complex structure. This embodiment can adjust the thickness of the phase change layer, dielectric layer, and metal layer structure and the state of the phase change layer according to actual applications to achieve the absorption ratio of light in a certain band, which can be applied to devices such as optical detectors, and has high practicality and broad application prospects.

[0060] 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 embodiments of the present invention.

Claims

1. A narrowband absorption device based on phase change material, characterized in that: include: A narrowband absorption cavity structure, comprising a metal layer, a dielectric layer and a phase change layer; A lithium tantalate single crystal structure, located below the narrow-band absorption cavity structure; When light hits the narrowband absorption cavity structure, the narrowband absorption cavity structure is used to absorb light of corresponding wavelength to produce a pyroelectric effect, and the lithium tantalate single crystal structure is used to generate current to obtain the light intensity information of the light according to the magnitude of the current, and change the state of the phase change layer according to the magnitude of the current to control the switching of the light.

2. The narrowband absorption device based on phase change material according to claim 1, characterized in that: The narrowband absorption cavity structure comprises a first metal layer, a first dielectric layer, a phase change layer, a second dielectric layer, a second metal layer and a third dielectric layer which are arranged in sequence from bottom to top.

3. The narrowband absorption device based on phase change material according to claim 2, characterized in that: The voltage applied to the first metal layer is regulated according to the magnitude of the current, and the ratio of crystallization and amorphization of the phase change material in the phase change layer is controlled to regulate the absorption of the light.

4. The narrowband absorption device based on phase change material according to claim 1, characterized in that: The phase change material used in the phase change layer has an optical loss greater than a first preset threshold value, and a refractive index less than a second preset threshold value; The reflectivity of the metal layer is greater than a third preset threshold.

5. The narrowband absorption device based on phase change material according to claim 1, characterized in that: The thickness of the phase change material used in the phase change layer is less than 1 micron.

6. The narrowband absorption device based on phase change material according to claim 1, characterized in that: There are a plurality of phase change layers, and each phase change layer comprises a phase change material layer and electrode layers located on both sides of the phase change material layer.

7. The narrowband absorption device based on phase change material according to claim 6, characterized in that: The electrode layer between two adjacent phase change material layers is shared.

8. The narrowband absorption device based on phase change material according to claim 2, characterized in that: A reflective layer is further included between the first metal layer and the first dielectric layer.

9. The narrowband absorption device based on phase change material according to claim 8, characterized in that: The first metal layer is W, the reflective layer is Ag, the first dielectric layer is TIO2, the phase change layer is GSST, the second dielectric layer is TIO2, the second metal layer is Ag, and the third dielectric layer is MgF2.

10. The narrowband absorption device based on phase change material according to claim 9, characterized in that: The thickness of the first metal layer is 200nm, the thickness of the reflective layer is 200nm, the thickness of the first dielectric layer is 78nm, the thickness of the phase change layer is 100nm, the thickness of the second dielectric layer is 78nm, the thickness of the second metal layer is 22nm, the thickness of the third dielectric layer is 22nm, and the thickness of the lithium tantalate single crystal structure is 75 microns.

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