Thin film electric frequency multiplication device based on band edge enhancement effect

Abstract

The invention relates to a band edge enhancement effect-based thin film electric frequency multiplication device, which is characterized in that when a fundamental wave is obliquely incident, voltage is applied to a first electrode layer and a second electrode layer, and the fundamental wave penetrates through the transparent first electrode layer and a thin film layer, is reflected by the second electrode layer and then penetrates out of the first electrode layer through the thin film layer. In the process, the band edge enhancement effect of the thin film layer is utilized to enhance the third-order nonlinear polarizability, so that the generation efficiency of the second harmonic has a sharp peak value at the position of a certain wavelength, and the frequency doubling light corresponding to the fundamental wavelength at the sharp peak value just covers the energy band of the thin film layer. Therefore, the generation efficiency of the second harmonic is greatly improved under the condition that the voltage is applied. Therefore, an extremely high modulation ratio is obtained, and the modulation depth is far higher than that of a traditional electric frequency multiplication device. According to the thin film electric frequency multiplication device based on the band edge enhancement effect, the purpose of using electric frequency multiplication in a nonlinear material to achieve strong modulation can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of band edge enhancement components, and in particular to a thin film electro-frequency doubling device based on band edge enhancement effect. Background Art

[0002] Dynamic control of nonlinear optical signals has important application value in optical modulation and switching technology. All-optical control schemes can be used to develop various switching technologies based on Kerr or free-carrier nonlinearity in semiconductor materials. In addition, control of nonlinear optical signals can also be achieved through electro-optical interaction.

[0003] In nonlinear optics, the frequency conversion process depends on the chemical composition of the material and the spatial symmetry of the optical crystal. Symmetry is particularly important for second-order nonlinear optical processes. In the electric dipole approximation, there is no second-order polarizability χ(2) in centrosymmetric materials, so second harmonic generation (SHG) has only been widely studied in natural crystals with broken central inversion symmetry. Although the inversion symmetry of traditional optical crystals can be broken by introducing stress, the modulation depth of the nonlinear optical polarizability of the hybrid system is very limited.

[0004] Electrically induced frequency doubling (EFISH), proposed in the early 1960s, provides an alternative approach to designing nonlinear optical modulators. Electric field induced second harmonic generation (EFISH) is a third-order nonlinear process caused by the interaction of an external bias electric field with two incident photons. During the EFISH process, an external static electric field can mix with the fundamental wave to generate second harmonics in nonlinear optical materials with large third-order polarizability. EFISH can be used to dynamically control the nonlinear optical response of materials and therefore has broad application prospects in active nonlinear devices. However, achieving strong modulation using EFISH has always been a huge challenge in traditional nonlinear materials. Summary of the invention

[0005] In order to solve the defect that it is difficult to achieve strong modulation by using electric frequency doubling in nonlinear materials, the present invention proposes a thin film electric frequency doubling device based on the band edge enhancement effect.

[0006] The technical solution adopted by the present invention is a thin film electrochromic frequency doubling device based on the band edge enhancement effect, comprising a transparent thin film layer with a band edge enhancement effect, a transparent first electrode layer and a second electrode layer capable of reflecting light are respectively arranged on both sides in the thickness direction of the thin film layer, and a voltage is applied between the first electrode layer and the second electrode layer.

[0007] Preferably, the thin film layer is made of an organic semiconductor material with a conjugated structure.

[0008] Preferably, the film layer is a PFO film.

[0009] Preferably, the thickness of the PFO film ranges from 50 nanometers to 500 nanometers.

[0010] Preferably, the first electrode layer is an indium tin oxide layer.

[0011] Preferably, the input wavelength ranges from 810 nanometers to 885 nanometers.

[0012] Preferably, the input wavelength ranges from 820 nanometers to 865 nanometers.

[0013] Preferably, the second electrode layer is an aluminum film.

[0014] Preferably, a DC voltage is applied between the first electrode layer and the second electrode layer.

[0015] Preferably, the thin film electrofrequency doubling device is packaged in a transparent packaging structure.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present application discloses a thin-film electro-frequency doubling device based on the band edge enhancement effect. When the fundamental wave is incident obliquely, a voltage is applied to the first electrode layer and the second electrode layer. The fundamental wave passes through the transparent first electrode layer and the thin film layer, is reflected by the second electrode layer, and then passes through the thin film layer and out of the first electrode layer. In this process, the band edge enhancement effect of the thin film layer is used to enhance the third-order nonlinear polarizability, so that the generation efficiency of the second harmonic has a sharp peak at a certain wavelength. The frequency doubling light corresponding to the fundamental wavelength at the sharp peak just covers the energy band of the thin film layer, thereby greatly improving the generation efficiency of the second harmonic when a voltage is applied. In addition, an extremely high modulation ratio is obtained, and its modulation depth is much higher than that of traditional electro-frequency doubling devices.

[0018] Compared with the prior art, the thin-film electro-frequency doubling device based on the band edge enhancement effect disclosed in the present application can achieve the purpose of using electro-frequency doubling to realize strong modulation in nonlinear materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention is described in detail below with reference to the embodiments and accompanying drawings, wherein:

[0020] Figure 1 A schematic diagram showing the principle of a thin-film electro-frequency doubling device based on a band edge enhancement effect provided in accordance with an embodiment of the present invention is shown;

[0021] Figure 2 The second harmonic spectrum of a thin-film electrically induced frequency doubling device based on the band edge enhancement effect provided by an embodiment of the present invention under two different applied voltages is shown;

[0022] Figure 3The second harmonic intensity spectrum under different applied voltages when the second harmonic wavelength is 420 nanometers generated in a thin-film electro-frequency doubling device based on the band edge enhancement effect provided by an embodiment of the present invention is shown;

[0023] Figure 4 The invention shows a processing flow chart of a method for preparing a thin-film electrically induced frequency doubling device based on a band edge enhancement effect provided in accordance with an embodiment of the invention.

[0024] Description of labels:

[0025] 1. Substrate; 2. Indium Tin Oxide; 3. PFO; 4. Aluminum Film; 5. Transparent Packaging Structure. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar components or components with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0027] The present invention discloses a thin film electro-frequency doubling device based on band edge enhancement effect, please refer to Figure 1 , including a transparent thin film layer with a band edge enhancement effect, a transparent first electrode layer and a second electrode layer that can reflect light are respectively arranged on both sides of the thin film layer in the thickness direction, and a voltage is applied between the first electrode layer and the second electrode layer.

[0028] When the fundamental wave is incident obliquely, a voltage is applied to the first electrode layer and the second electrode layer. The fundamental wave passes through the transparent first electrode layer and the thin film layer, is reflected by the second electrode layer, and then passes through the thin film layer and out of the first electrode layer. In this process, the band edge enhancement effect of the thin film layer is used to enhance the third-order nonlinear polarizability, so that the generation efficiency of the second harmonic appears a sharp peak at a certain wavelength. The frequency-doubled light corresponding to the fundamental wavelength at the sharp peak just covers the energy band of the thin film layer, thereby greatly improving the generation efficiency of the second harmonic when a voltage is applied. In addition, an extremely high modulation ratio is obtained, and its modulation depth is much higher than that of a traditional electro-induced frequency doubling device. Compared with the prior art, a thin film electro-induced frequency doubling device based on the band edge enhancement effect disclosed in the present application can achieve the purpose of using electro-induced frequency doubling to achieve strong modulation in nonlinear materials.

[0029] Figure 1A schematic diagram of a thin-film electro-frequency doubling device based on the band edge enhancement effect is disclosed. The "sandwich structure" micro-nano optoelectronic device is composed of a metal reflective layer of aluminum, an organic semiconductor PFO, and a transparent electrode ITO. Under the incidence of transverse magnetic light waves and the action of an external DC electric field, a huge electro-frequency doubling effect is generated.

[0030] Specifically, the band edge enhancement effect refers to the fact that for organic or inorganic semiconductors, when the incident photon energy is close to the band gap, the semiconductor's absorption and radiation of light of this wavelength will be enhanced, which indicates the direct transition of carriers from the conduction band to the valence band in the semiconductor. Therefore, in the process of nonlinear optics, the band edge enhancement effect makes the intensity or response of the electromagnetic field at the edge of the band structure enhanced, and the radiation of nonlinear harmonics enhanced. At this time, the frequency-doubled light corresponding to the fundamental wavelength at the sharp peak can cover the energy band of the thin film layer, that is, the energy range of the frequency-doubled light can cover or cross the energy band to excite the electrons in the energy band to make transitions, thereby changing the electronic structure and properties of the thin film layer.

[0031] Among them, for thin film layers made of different materials, the band edge enhancement effect that can be obtained according to their own properties is not the same, and the value of the fundamental wavelength at the location of the corresponding sharp peak is also different. The fundamental wavelength at the sharp peak is mainly related to the material properties of the thin film layer, and the thickness of the thin film layer has almost no effect on the location of the sharp peak wavelength. In the consideration of this project, since there is no complex resonance effect involved, the peak value of the fundamental wavelength mainly depends on the material properties of the thin film layer itself.

[0032] It should be explained that the fundamental wavelength at the sharp peak has the maximum second harmonic generation gain, and the fundamental wavelengths on both sides of the sharp peak also have a certain gain effect, and the maximum second harmonic generation gain obtained at this time does not change with the change of the applied voltage.

[0033] Regarding the question of how to ensure that the frequency-doubled light just covers the energy band of the thin film layer, first, select the material of the thin film layer: in the design of actual devices, the material is first selected (such as PFO), and its band gap energy is also fixed. Secondly, determine the wavelength according to the band gap energy: select the appropriate fundamental wavelength according to the band gap energy of the material to ensure that the energy of the frequency-doubled light is closest to the band gap energy of the material, thereby achieving the best frequency-doubled generation. Finally, when the energy of the frequency-doubled light is closest to the band gap energy, the second harmonic intensity reaches its peak: this is the concrete manifestation of the band edge enhancement effect, and the resonance enhancement of the frequency-doubled light can maximize the intensity of the second harmonic signal.

[0034] In the present invention, when the fundamental wave is incident obliquely, a second harmonic can be generated in the organic polymer film layer. The reflected second harmonic intensity of the device can be described as: Among them, Eω is the electric field of the fundamental wave; EDC is the external electric field applied to the organic polymer thin film layer through the transparent electrode (first electrode layer) and the metal electrode (second electrode layer); χ(2) and χ(3) are the effective second-order and third-order polarizabilities of the organic polymer thin film layer, respectively. χ(2) is the second harmonic generated at the interface of the metal-organic polymer or ITO-organic polymer thin film layer. The first and third terms describe the electro-induced frequency doubling process and the conventional second harmonic process, respectively, while the second term represents the interference between the two, which depends on both the χ(2) and χ(3) coefficients of the system. This is contrary to the results of most active material studies, in which χ(3) plays a dominant role. Due to the coupling of the fundamental electric field with the DC field in the second term of the equation, the intensity of the electro-induced frequency doubling can also be adjusted by the sign of the DC field applied by the switch.

[0035] When the fundamental wave is incident normally on the "sandwich structure" electro-frequency doubling thin film electro-frequency doubling device, the generation of second harmonics in the organic polymer film layer is prohibited because the second-order polarizability χ(2) in the uniform film can be ignored.

[0036] The first electrode layer of the thin-film electro-frequency multiplier device with edge enhancement effect is connected to the anode / cathode of a DC power supply to apply positive / negative voltage. The transparent first electrode layer can be used as both an anode (U>0) and a cathode (U<0). Figure 2 As shown, by applying an external voltage to the first electrode layer and the second electrode layer and utilizing the oblique incidence of the fundamental wave, the external electrostatic field can be mixed with the fundamental wave (FW) to generate second harmonics in an organic polymer material with a large third-order polarizability. The device can strongly enhance the generation efficiency of the second harmonics.

[0037] In other application scenarios, electro-induced frequency doubling is a special case of third-order nonlinear optics. When an AC voltage is applied, a third-order nonlinear effect can also be generated. For common AC frequencies, it does not affect the normal operation of the device. The first electrode layer and the second electrode layer can also be connected to an AC power supply and used in application scenarios that require rapid response or multi-switch control.

[0038] In some embodiments, the thin film layer is made of an organic semiconductor material with a conjugated structure.

[0039] On the one hand, materials with conjugated structures usually have a delocalized π electron system. These π electrons can move freely throughout the molecular skeleton. The delocalization of this electron significantly enhances the third-order nonlinear polarizability χ(3) of the material, resulting in a higher nonlinear optical response. On the other hand, materials with conjugated structures usually have good solution processability, which is very advantageous in the preparation of optical films.

[0040] The advantages of conjugated organic semiconductors are: 1. Compared with ordinary organic matter, the conjugated structure has a larger nonlinear polarizability; 2. Compared with inorganic semiconductors, organic semiconductors can be processed and realized with simple spin coating; 3. Conjugated organic semiconductors can adjust the wavelength of the band edge effect by changing the chemical synthesis method.

[0041] In some embodiments, the film layer is a PFO film.

[0042] The fundamental wavelength at the sharp peak is related to the characteristics of PFO itself. When the fundamental wavelength is 840nm, the wavelength of the second harmonic (doubled frequency) light is 420nm, which is closest to the band gap of PFO. This enhances the nonlinear polarization response of the material, causing the second harmonic generation efficiency to reach a peak at this wavelength.

[0043] Specifically, PFO is polyoctylfluorene (Poly (9,9-di-n-octyl-2,7-fluorene). As a conjugated organic semiconductor material, the π electron conjugated system in its molecular structure enables PFO to have good optical absorption and emission properties in the visible light range, and the molecular chain of PFO can present chain conformations with various torsion angles. The stability of these chain conformations has an important influence on the improvement of the band edge enhancement effect of PFO. Therefore, the film layer of this application is selected as PFO film.

[0044] In other embodiments, other organic conjugated polymer materials with band edge enhancement effect and transparency can also be selected. In addition to PFO, other conjugated organic semiconductor films can also be selected as nonlinear materials, such as BEHP-PPV, MEH-PPV, etc. These organic semiconductors have large nonlinear polarizability, and the wavelength of the band edge effect can be adjusted to cover almost the entire visible light range by adjusting the mixing ratio of these organic semiconductors. In addition to the organic conjugated polymers listed below, such as MEH-PPV and BEHP-PPV, some perovskite materials and two-dimensional materials such as ZnO, transition metal disulfide compounds (WS2, MoS2, etc.) can also be selected as thin film layers.

[0045] In some specific embodiments, the PFO film has a thickness ranging from 50 nanometers to 500 nanometers.

[0046] It should be noted that the thickness range of the PFO film is limited to between 50 nanometers and 500 nanometers. On the one hand, this thickness range can meet the relatively basic band edge enhancement effect strength of the PFO film. On the other hand, the PFO film in this thickness range can present a more transparent material to meet better optical properties during operation. On the other hand, this thickness range can make the thin-film electrochromic frequency doubling device have a lighter texture, which is suitable for use in a variety of scenarios.

[0047] Preferably, it has been verified through experiments that when the thickness of the PFO film is 100 nanometers, the optical properties of the PFO film and the strength of its band edge enhancement effect can reach the best matching value, thereby enabling the thin film electro-frequency doubling device to have a stronger performance.

[0048] In some specific embodiments, the first electrode layer is an optical crystal with spatial symmetry.

[0049] In other embodiments, the first electrode layer is composed of a first part with non-spatial symmetry and a second part with spatial symmetry, so that when the fundamental wave is incident and reflected in the first part or the second part, the second harmonic value generated is different, which provides more options for the input and output mode of the thin film electro-frequency multiplier device. It should be noted that some materials can form crystals with spatial symmetry and optical crystals with non-spatial symmetry respectively according to their different preparation processes, so the first part and the second part can be made of the same material or different materials.

[0050] In some more specific embodiments, the first electrode layer is an indium tin oxide layer.

[0051] Among them, indium tin oxide (ITO) is a substitutional solid solution and also a metal oxide material with excellent electrical properties. It is transparent and colorless in a thin film state and has excellent transparency in this state. Using an indium tin oxide layer as a transparent first electrode layer can minimize the impact of the first electrode layer on the PFO thin film layer. Preferably, the thickness of the indium tin oxide layer ranges from 50 nanometers to 500 nanometers. It should be noted that the thickness selection of indium tin oxide needs to be selected according to the magnitude of the applied voltage. This is because high concentrations of charge carriers increase the conductivity of the material, but also reduce its transparency. Controlling the thickness range of the indium tin oxide layer within 50 nanometers to 500 nanometers is conducive to controlling the magnitude of the applied voltage within a smaller range, so that indium tin oxide maintains its excellent transparent properties.

[0052] like Figure 3 As shown, Figure 3The second harmonic intensity spectrum under different applied voltages when the second harmonic wavelength is 420nm. As the applied DC voltage changes, the experimental second harmonic intensity is consistent with the nonlinear polarization theory. At the resonant wavelength of 840nm, regardless of the applied DC electric field, the second harmonic always has the highest efficiency for this electro-optical frequency doubling device. When the applied voltage is changed, the intensity of the second harmonic drops to the minimum value at U=1.5V, then increases rapidly, and increases to the maximum value at U=6V. The device has an extremely high modulation ratio. If a reverse voltage is applied to the device, the electro-optical frequency doubling of the electro-optical device exhibits very unusual behavior. When U is swept from 0 to -6V, the intensity of the second harmonic continues to increase, and there is also an extremely high SHG negative modulation depth.

[0053] In some further specific embodiments, the input wavelength ranges from 810 nanometers to 885 nanometers.

[0054] Specifically, please refer to Figure 2 , spectra of the second harmonics under two different applied voltages. In the absence of an external DC electric field, the sandwich-structured micro-nano device exhibits a very weak second harmonic efficiency (the triangle line in the figure). When the applied DC voltage is 6V (the dotted line in the figure), the second harmonic generation efficiency is greatly improved, and reaches a maximum value at a pump wavelength of 840nm. The second harmonics generated at this wavelength (wavelength 420nm) correspond to the energy band width of the organic semiconductor PFO, indicating that the band edge enhances the generation of electro-induced frequency doubling. When the input wavelength range is 810nm to 885nm, its SHG gain is above 0.3, thus obtaining a better gain effect.

[0055] In some particularly specific embodiments, the input wavelength ranges from 820 nanometers to 865 nanometers.

[0056] Among them, Figure 2 It can be seen that when the input wavelength ranges from 820 nanometers to 865 nanometers, the SHG gain is above 0.6, thereby obtaining a better gain effect. If the best gain effect is required, the input wavelength can be set to 840 nanometers, at which time the efficiency of second harmonic generation is at its maximum.

[0057] In some embodiments, the second electrode layer is an aluminum thin film.

[0058] Specifically, the second electrode layer can be made of metal, preferably aluminum film, which has excellent electrical properties and can reflect the fundamental wave. Preferably, the thickness of the aluminum film is 100 nanometers to keep the thin film electro-frequency doubling device at the nanometer level.

[0059] In some embodiments, a DC voltage is applied between the first electrode layer and the second electrode layer.

[0060] A DC voltage is applied to the first electrode layer and the second electrode layer, so that the electro-frequency doubling device can obtain a stable second harmonic, and its robust performance is higher. At a resonant wavelength of 840nm, regardless of the DC electric field applied, the second harmonic always has the highest efficiency for the electro-frequency doubling optoelectronic device. Figure 3 As shown, when the applied voltage is changed, the intensity of the second harmonic drops to the minimum value at U=1.5V, then increases rapidly, and reaches the highest value at U=6V. The thin film electro-frequency doubling device has an extremely high modulation ratio.

[0061] In some embodiments, the thin film electro-frequency doubling device is packaged in a transparent packaging structure.

[0062] The thin film electro-frequency doubling device is placed in a chamber surrounded by a substrate and a transparent packaging structure, thereby providing good protection for the thin film electro-frequency doubling device and preventing it from being damaged and affecting the normal realization of its functions.

[0063] The present invention also discloses a method for preparing a thin film electro-frequency doubling device based on the band edge enhancement effect, comprising:

[0064] preparing an indium tin oxide thin film as a first electrode layer on a substrate;

[0065] Coating a uniform PFO thin film layer on the first electrode layer;

[0066] An aluminum film is plated on the PFO film layer as a second electrode layer.

[0067] In some particularly specific embodiments, comprising:

[0068] An indium tin oxide (ITO) film is prepared on a substrate 1 as a transparent electrode layer 2. Figure 4 a;

[0069] A uniform 100 nm organic polymer PFO film 3 was prepared by spin coating on the transparent electrode layer 2. Figure 4 b;

[0070] Thermal evaporation coating was performed on the organic polymer film layer to obtain 100 nm aluminum as the electrode layer 4. Figure 4 c;

[0071] The prepared thin film electrofrequency doubling device is packaged using a transparent packaging structure 5, such as epoxy resin, and connected to an external power supply to obtain a thin film electrofrequency doubling device. Figure 4 d.

[0072] In the description of this specification, if the terms "embodiment one", "this embodiment", "in an embodiment" and the like appear, it means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in the invention or at least one embodiment or example of the invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example; moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in an appropriate manner.

[0073] In the description of this specification, the terms "connect", "install", "fix", "set", "have", etc. are all understood in a broad sense. For example, "connection" 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 a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0074] In the description of this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0075] The above description of the embodiments is to facilitate ordinary technicians in the technical field to understand and apply the technology of this case. People familiar with the technology in this field can obviously easily make various modifications to these examples and apply the general principles described here to other embodiments without creative work. Therefore, this case is not limited to the above embodiments. Modifications to the following situations should all be within the scope of protection of this case: ① A new technical solution implemented based on the technical solution of the present invention and combined with existing common knowledge, the technical effect produced by the new technical solution does not exceed the technical effect of the present invention; ② The equivalent replacement of some features of the technical solution of the present invention by using known technology, the technical effect produced is the same as the technical effect of the present invention; ③ The technical solution of the present invention can be expanded, and the substantive content of the expanded technical solution does not exceed the technical solution of the present invention; ④ The equivalent transformation made by using the contents of the description and drawings of the present invention is directly or indirectly applied to other related technical fields.

Claims

1. A thin film electro-frequency doubling device based on band edge enhancement effect, characterized in that: It comprises a transparent thin film layer with edge enhancement effect, a transparent first electrode layer and a second electrode layer capable of reflecting light are arranged on both sides of the thin film layer in the thickness direction, and a voltage is applied between the first electrode layer and the second electrode layer.

2. A thin film electro-frequency doubling device based on band edge enhancement effect according to claim 1, characterized in that: The thin film layer is made of an organic semiconductor material with a conjugated structure.

3. The thin film electro-frequency doubling device based on band edge enhancement effect according to claim 2, characterized in that: The film layer is a PFO film.

4. The thin film electro-frequency doubling device based on band edge enhancement effect according to claim 3, characterized in that: The thickness of the PFO film ranges from 50 nanometers to 500 nanometers.

5. The thin film electro-frequency doubling device based on band edge enhancement effect according to claim 3, characterized in that: The first electrode layer is an indium tin oxide layer.

6. The thin film electro-frequency doubling device based on band edge enhancement effect according to claim 5, characterized in that: The input wavelength range is 810 nm to 885 nm.

7. The thin film electro-frequency doubling device based on band edge enhancement effect according to claim 6, characterized in that: The input wavelength ranges from 820 nanometers to 865 nanometers.

8. The thin film electro-frequency doubling device based on band edge enhancement effect according to claim 1, characterized in that: The second electrode layer is an aluminum thin film.

9. A thin film electro-frequency doubling device based on band edge enhancement effect according to any one of claims 1 to 8, characterized in that: A direct current voltage is applied between the first electrode layer and the second electrode layer.

10. A thin film electro-frequency doubling device based on band edge enhancement effect according to any one of claims 1 to 8, characterized in that: The thin film electro-frequency doubling device is packaged in a transparent packaging structure.

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