A broadband high-transmittance tuning ratio optical switch and its preparation method

Abstract

A broadband high-transmittance tuning ratio optical switch and its preparation method, which belongs to the field of smart materials and optical films. The present invention aims to solve the problems of existing optical switches, such as low transmittance and narrow bandwidth, and the long recovery time required to return to the initial high-transmittance state with the help of external stimulation once a phase change occurs. The broadband high-transmittance tuning ratio optical switch is composed of a transparent substrate, an anti-reflection layer and a VO2 layer; the anti-reflection layer and the VO2 layer are arranged on both sides of the transparent substrate from the inside to the outside; or the anti-reflection layer and the VO2 layer are arranged on one side of the transparent substrate from the inside to the outside, and the anti-reflection layer is arranged on the other side. Preparation method: 1. Cleaning the substrate; 2. Preparing the anti-reflection layer; 3. Preparing the VO2 layer. The present invention is used for a broadband high-transmittance tuning ratio optical switch and its preparation.

Description

Technical Field

[0001] The invention belongs to the field of smart materials and optical films. Background Art

[0002] An optical switch is a nonlinear device whose transmittance decreases with increasing incident light intensity, protecting sensitive optical components from laser damage. Recent research has found that devices based on multilayer photonic crystal structures and phase-change materials can achieve optical switching, transitioning from a high-transmittance state for low-intensity light to a high-intensity reflection or absorption state. However, multilayer photonic crystal structures have a large quality factor, resulting in low transmittance and a narrow bandwidth. Furthermore, non-volatile phase-change materials such as Ge2Sb2Te5 (GST), despite their large optical nonlinearity, require external stimulation once a phase transition occurs and require a long time to return to their initial high-transmittance state, resulting in only a single switching transition. Summary of the Invention

[0003] The present invention aims to solve the problems of existing optical switches, such as low transmittance and narrow bandwidth, and long recovery time after phase change, which requires external stimulation to return to the initial high transmittance state. The present invention provides a broadband high transmittance tuning ratio optical switch and its preparation method.

[0004] A broadband high-transmittance tuning ratio optical switch, comprising a transparent substrate, an anti-reflection layer and a VO2 layer; the thickness of the anti-reflection layer is 300nm~1000nm;

[0005] When both sides of the transparent substrate are provided with an anti-reflection layer and a VO2 layer with a thickness of 20nm to 100nm in sequence from the inside to the outside, the broadband high-transmittance tuning ratio optical switch has a low-temperature transmittance greater than -0.87dB at 35°C, and a maximum transmittance switching ratio of 23.93dB.

[0006] When an anti-reflection layer and a VO2 layer with a thickness of 20nm to 400nm are sequentially arranged on one side of the transparent substrate from the inside to the outside, and an anti-reflection layer is arranged on the other side, the broadband high-transmittance tuning ratio optical switch has a low-temperature transmittance greater than -2.22dB at 35°C, and the maximum transmittance switching ratio is 38.68dB.

[0007] A method for preparing a broadband high-transmittance tuning ratio optical switch is carried out according to the following steps:

[0008] 1. Cleaning the substrate:

[0009] polishing and cleaning the transparent substrate to obtain a pretreated transparent substrate;

[0010] 2. Preparation of anti-reflection layer:

[0011] Using magnetron sputtering, electron beam evaporation, pulsed laser deposition or atomic layer deposition, an antireflection layer is formed on both sides of the pretreated transparent substrate;

[0012] 3. VO2 layer preparation:

[0013] By using magnetron sputtering, electron beam evaporation, pulsed laser deposition or atomic layer deposition, a VO2 layer is prepared on the surface of one or both sides of the anti-reflection layer to obtain a broadband high transmission tuning ratio optical switch.

[0014] The beneficial effects of the present invention are:

[0015] The present invention utilizes the transmittance-enhancing effect of double-sided HfO2 and the characteristics of VO2, such as sudden change in optical transmittance with temperature, rapid phase change, easy recovery of phase change and high number of cycles, to achieve infrared transmittance enhancement, increased transmittance tuning ratio and fast response time. The transmittance peak position is dynamically adjusted by changing the thickness of HfO2. When the VO2 layer is single-sided, the high and low temperature transmittance and transmittance switching ratio can be dynamically regulated by the thickness of VO2. When the VO2 layer is double-sided, a high low-temperature transmittance, a wide transmittance band and a large transmittance switching ratio can be obtained by the thickness of VO2, and it can be reused many times, so that the infrared detector meets the needs of laser protection. The prepared optical switch can perform infrared imaging at low temperatures to realize infrared detection, and can perform laser protection at high temperatures to protect sensitive optical components and human eyes from damage. Because the transmittance-enhancing layer and VO2 can be obtained by a variety of preparation methods, the preparation process is diverse.

[0016] The present invention is used for a broadband high-transmittance tuning ratio optical switch and a preparation method thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of a broadband high-transmittance tuning ratio optical switch in the present invention when a VO2 layer is provided on one side of a transparent substrate, 1 is the transparent substrate, 2 is the anti-reflection layer, and 3 is the VO2 layer;

[0018] Figure 2 Schematic diagram of the structure of the broadband high-transmittance tuning ratio optical switch of the present invention when VO2 layers are provided on both sides of the transparent substrate, 1 is the transparent substrate, 2 is the anti-reflection layer, and 3 is the VO2 layer;

[0019] Figure 3 This is a comparison chart of the transmittance of the broadband high transmittance tuning ratio optical switch at different temperatures in Example 1;

[0020] Figure 4 This is a comparison chart of the transmittance of the broadband high transmittance tuning ratio optical switch at different temperatures in Example 2;

[0021] Figure 5 This is a comparison chart of the transmittance of the broadband high-transmittance tuning ratio optical switch at different temperatures in Example 3;

[0022] Figure 6 This is a comparison chart of the transmittance of the broadband high transmittance tuning ratio optical switch at different temperatures in Example 4;

[0023] Figure 7 This is a comparison chart of the transmittance of the broadband high transmittance tuning ratio optical switch at different temperatures in Example 5;

[0024] Figure 8 This is a comparison chart of the transmittance of the broadband high-transmittance tuning ratio optical switch at different temperatures in Example 6;

[0025] Figure 9 This is a comparison chart of the transmittance of the broadband high-transmittance tuning ratio optical switch at different temperatures according to Example 7;

[0026] Figure 10 This is a comparison chart of the transmittance of the broadband high-transmittance tuning ratio optical switch at different temperatures in Example 8;

[0027] Figure 11 This is a comparison chart of the transmittance of the broadband high-transmittance tuning ratio optical switch of Example 9 at different temperatures. DETAILED DESCRIPTION

[0028] Specific implementation method 1: Combination Figure 1 and 2 Specifically describing this embodiment, this embodiment is a broadband high-transmittance tuning ratio optical switch, which is composed of a transparent substrate, an anti-reflection layer and a VO2 layer; the thickness of the anti-reflection layer is 300nm~1000nm;

[0029] When both sides of the transparent substrate are provided with an anti-reflection layer and a VO2 layer with a thickness of 20nm to 100nm in sequence from the inside to the outside, the broadband high-transmittance tuning ratio optical switch has a low-temperature transmittance greater than -0.87dB at 35°C, and a maximum transmittance switching ratio of 23.93dB.

[0030] When an anti-reflection layer and a VO2 layer with a thickness of 20nm to 400nm are sequentially arranged on one side of the transparent substrate from the inside to the outside, and an anti-reflection layer is arranged on the other side, the broadband high-transmittance tuning ratio optical switch has a low-temperature transmittance greater than -2.22dB at 35°C, and the maximum transmittance switching ratio is 38.68dB.

[0031] VO2 is a thermochromic material whose optical and electrical properties undergo dramatic changes as the temperature rises. Specifically, at low temperatures, the VO2 film has high transmittance in the infrared band; at high temperatures, infrared light is reflected by the VO2 film, exhibiting low transmittance. It also has a fast phase change speed, a low phase change threshold, and a large transmittance tuning ratio, making it very suitable for use in optical switches.

[0032] This specific embodiment is based on the volatile phase-change material VO2, utilizing its phase-change optical transmittance mutation and the ability to undergo multiple cycles, combined with the transmittance-enhancing effect of a double-sided anti-reflection layer. By adjusting the thickness of the anti-reflection layer, the transmission peak position can be regulated between 3μm and 11μm. By changing the transmittance of VO2, a large transmittance switching ratio and a large bandwidth can be achieved, thereby achieving the performance of dynamically adjustable peak position and transmittance. By doping VO2 with different elements and concentrations, dynamic regulation of the phase change temperature can be achieved.

[0033] The beneficial effects of this embodiment are:

[0034] This embodiment utilizes the transmittance-enhancing effect of double-sided HfO2 and the characteristics of VO2's optical transmittance that undergoes sudden changes with temperature, rapid phase changes, easy phase change recovery, and a high number of cycles, to achieve infrared transmittance enhancement, increased transmittance tuning ratio, and fast response time. The transmittance peak position is dynamically adjusted by changing the thickness of HfO2. When the VO2 layer is single-sided, the high and low temperature transmittance and transmittance switching ratio can be dynamically regulated by the thickness of VO2. When the VO2 layer is double-sided, a high low-temperature transmittance, a wide transmittance bandwidth, and a large transmittance switching ratio can be obtained by the thickness of VO2, and it can be reused many times, so that the infrared detector meets the needs of laser protection. The prepared optical switch can perform infrared imaging at low temperatures to achieve infrared detection, and can perform laser protection at high temperatures to protect sensitive optical components and human eyes from damage. Because the transmittance-enhancing layer and VO2 can be obtained using a variety of preparation methods, the preparation process is diverse.

[0035] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the transparent substrate has a transmittance of more than -2.6 dB in the 2.5 μm to 25 μm band. Other aspects are the same as specific embodiment 1.

[0036] Specific embodiment 3: This embodiment differs from specific embodiment 1 or 2 in that the anti-reflection layer has a transmittance of greater than -0.09 dB in the 2 μm to 10 μm band. Other aspects are the same as specific embodiment 1 or 2.

[0037] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the transparent substrate is a Si substrate, a sapphire substrate or a gallium arsenide substrate. Other aspects are the same as specific embodiments 1 to 3.

[0038] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that the anti-reflection layer is a HfO2 layer, an Al2O3 layer, a ZrO2 layer, a TiO2 layer, a CaF2 layer, or a Cr2O3 layer. Other aspects are the same as specific embodiments 1 to 4.

[0039] Specific embodiment 6: This embodiment provides a method for preparing a broadband high-transmittance tuning ratio optical switch, which is carried out according to the following steps:

[0040] 1. Cleaning the substrate:

[0041] polishing and cleaning the transparent substrate to obtain a pretreated transparent substrate;

[0042] 2. Preparation of anti-reflection layer:

[0043] Using magnetron sputtering, electron beam evaporation, pulsed laser deposition or atomic layer deposition, an antireflection layer is formed on both sides of the pretreated transparent substrate;

[0044] 3. VO2 layer preparation:

[0045] By using magnetron sputtering, electron beam evaporation, pulsed laser deposition or atomic layer deposition, a VO2 layer is prepared on the surface of one or both sides of the anti-reflection layer to obtain a broadband high transmission tuning ratio optical switch.

[0046] Specific embodiment seven: This embodiment differs from specific embodiment six in that: when the anti-reflection layer is a HfO2 layer, step two uses DC reactive magnetron sputtering to prepare an anti-reflection layer on both sides of the pre-treated transparent substrate, specifically, the following steps are performed: evacuate the vacuum chamber to 1×10 -3 Pa~5×10 -3 Pa, then the pretreated transparent substrate is heated to 200°C to 400°C, and a metal Hf target is used as the target material. Ar gas is introduced, and pre-sputtering is performed for 10 minutes to 30 minutes at a pre-sputtering pressure of 0.5 Pa to 1.0 Pa. O2 gas is then introduced, and sputtering is performed under the conditions of an Ar gas flow rate of 75 sccm to 85 sccm, an O2 gas flow rate of 4 sccm to 5 sccm, an operating pressure of 0.5 Pa to 1 Pa, and a sputtering power of 180 W to 220 W. Other steps are the same as those in the sixth embodiment.

[0047] Specific embodiment eight: This embodiment differs from either specific embodiment six or seven in that: when the anti-reflection layer is a HfO2 layer, step two uses electron beam evaporation to prepare an anti-reflection layer on both sides of the pre-treated transparent substrate, specifically by the following steps: evacuate the vacuum chamber to 2×10 -3 Pa~5×10 -3 Pa, then the pretreated transparent substrate is heated to 200°C to 400°C, and HfO2 particles are used as film material under the conditions of working pressure of 0.02Pa to 0.05Pa and electron beam current of 100mA to 130mA. Other steps are the same as those in the sixth or seventh embodiment.

[0048] Specific embodiment 9: This embodiment differs from any one of specific embodiments 6 to 8 in that: when the anti-reflection layer is a HfO2 layer, step 2 uses pulsed laser deposition to prepare an anti-reflection layer on both sides of the pre-treated transparent substrate, specifically by the following steps: evacuate the vacuum chamber to 1×10 -3 Pa~5×10 -3 Pa, then the pretreated transparent substrate is heated to 350°C to 600°C, and hafnium oxide is used as a target. O2 gas is introduced into a vacuum chamber, and sputtering is performed under the conditions of an O2 gas flow rate of 1.5 sccm to 2.5 sccm, a laser frequency of 5 Hz, an energy per pulse of 100 mJ to 200 mJ, and a deposition pressure of 0.2 Pa to 0.5 Pa. Other steps are the same as those in specific embodiments 6 to 8.

[0049] Specific embodiment 10: The difference between this embodiment and any one of specific embodiments 6 to 9 is that: Step 3 is to prepare a VO2 layer on one or both sides of the anti-reflection layer by using high-energy pulse reactive magnetron sputtering. Specifically, the steps are as follows: evacuate the vacuum chamber to 4×10 -4 Pa~6×10 -4 Pa, then the substrate is heated to 450°C to 600°C, and a metal V target is used as the target material. Ar gas is introduced, and pre-sputtering is performed for 10 minutes to 30 minutes at a pre-sputtering pressure of 0.5 Pa to 1.0 Pa. O2 gas is then introduced, and sputtering is performed under the following conditions: an Ar gas flow rate of 75 sccm to 85 sccm, an O2 gas flow rate of 1.5 sccm to 2.2 sccm, an operating pressure of 0.9 Pa, a sputtering power of 180 W to 220 W, a pulse frequency of 400 kHz, and a duty cycle of 1%. Other conditions are the same as those of specific embodiments 6 to 9.

[0050] The following examples are used to verify the beneficial effects of the present invention:

[0051] Example 1:

[0052] A broadband high-transmittance tuning ratio optical switch, comprising a transparent substrate, an anti-reflection layer and a VO2 layer; the anti-reflection layer has a thickness of 300 nm;

[0053] An anti-reflection layer and a 60nm thick VO2 layer are sequentially provided on both sides of the transparent substrate from the inside to the outside;

[0054] The transparent substrate is a Si substrate; the anti-reflection layer is a HfO2 layer with a transmittance of -0.09dB.

[0055] The method for preparing the broadband high-transmittance tuning ratio optical switch is carried out according to the following steps:

[0056] 1. Cleaning the substrate:

[0057] polishing and cleaning both sides of the transparent substrate to obtain a pretreated transparent substrate;

[0058] 2. Preparation of anti-reflection layer:

[0059] Using DC reactive magnetron sputtering, an antireflection layer is prepared on both sides of the pretreated transparent substrate;

[0060] 3. VO2 layer preparation:

[0061] By using high-energy pulse reactive magnetron sputtering, VO2 layers were prepared on the surface of the anti-reflection layers on both sides to obtain a broadband high-transmittance tuning ratio optical switch.

[0062] The antireflection layer is prepared on both sides of the pretreated transparent substrate by DC reactive magnetron sputtering in step 2. Specifically, the process is as follows: evacuate the vacuum chamber to 2.9×10 -3 Pa, and then the pretreated transparent substrate was heated to 400 ° C, and a metal Hf target with a purity of 99.99% was used as the target material, and Ar gas with a purity of 99.99% was introduced. Under the pre-sputtering pressure of 0.9 Pa, pre-sputtering was carried out for 15 minutes, and then O2 gas with a purity of 99.99% was introduced. Under the conditions of Ar gas flow rate of 81 sccm, O2 gas flow rate of 4.4 sccm, working pressure of 0.9 Pa and sputtering power of 210 W, sputtering was carried out for 1 hour.

[0063] In step 3, VO2 layer is prepared on the surface of the antireflection layer on both sides by high energy pulse reactive magnetron sputtering. Specifically, the following steps are performed: evacuate the vacuum chamber to 4.2×10 -4 Pa, and then heat the substrate to 550 ° C, use a metal V target with a purity of 99.999% as the target material, introduce Ar gas with a purity of 99.99%, and pre-sputter for 15 minutes at a pre-sputtering pressure of 0.9 Pa. Then introduce O2 gas with a purity of 99.99%, and sputter for 30 minutes at an Ar gas flow rate of 81 sccm, an O2 gas flow rate of 1.9 sccm, a working pressure of 0.9 Pa, a sputtering power of 200 W, a pulse frequency of 400 kHz and a duty cycle of 1%.

[0064] Figure 3 This is a comparison chart of the transmittance of the broadband high-transmittance tuning ratio optical switch of Example 1 at different temperatures. As can be seen from the figure, the low-temperature transmittance peak is at 3.8μm, the transmittance is -0.58dB at a low temperature of 35℃, and the transmittance is -23.07dB at a high temperature of 70℃, with a transmittance switching ratio of 22.49dB.

[0065] Example 2: This example differs from Example 1 in that it provides a broadband, high-transmittance, tunable-ratio optical switch comprising a transparent substrate, an anti-reflection layer, and a VO2 layer; the anti-reflection layer is 450 nm thick; an anti-reflection layer and a 60 nm thick VO2 layer are sequentially disposed on both sides of the transparent substrate, from the inside out; the transparent substrate is a Si substrate; the anti-reflection layer is an HfO2 layer with a transmittance of -0.09 dB; and in step 2, the HfO2 anti-reflection layer is prepared by DC reactive magnetron sputtering for 1.5 hours. Other aspects are the same as in Example 1.

[0066] Figure 4 This is a comparison chart of the transmittance of the broadband high-transmittance tuning ratio optical switch of Example 2 at different temperatures. As can be seen from the figure, the low-temperature transmittance peak is at 5μm, the transmittance is -0.34dB at a low temperature of 35℃, and the transmittance is -21.54dB at a high temperature of 70℃, with a transmittance switching ratio of 21.2dB.

[0067] Example 3: This example differs from Example 1 in that: a broadband, high-transmittance, tunable-ratio optical switch is provided. The broadband, high-transmittance, tunable-ratio optical switch comprises a transparent substrate, an anti-reflection layer, and a VO2 layer; the anti-reflection layer is 650 nm thick; an anti-reflection layer and a 60 nm thick VO2 layer are sequentially disposed on both sides of the transparent substrate, from the inside out; the transparent substrate is a Si substrate; the anti-reflection layer is an HfO2 layer with a transmittance of -0.09 dB; and in step 2, when the HfO2 anti-reflection layer is prepared by DC reactive magnetron sputtering, the sputtering time is 2 hours. All other aspects are the same as in Example 1.

[0068] Figure 5 This is a comparison chart of the transmittance of the broadband high-transmittance tuning ratio optical switch of Example 3 at different temperatures. As can be seen from the figure, the low-temperature transmittance peak is at 6.4μm, the transmittance is -0.43dB at a low temperature of 35℃, and the transmittance is -24.36dB at a high temperature of 70℃, with a transmittance switching ratio of 23.93dB.

[0069] Example 4: This example differs from Example 1 in that: a broadband, high-transmittance, tunable-ratio optical switch is provided. The broadband, high-transmittance, tunable-ratio optical switch comprises a transparent substrate, an anti-reflection layer, and a VO2 layer; the anti-reflection layer is 750 nm thick; an anti-reflection layer and a 60 nm thick VO2 layer are sequentially disposed on both sides of the transparent substrate, from the inside out; the transparent substrate is a Si substrate; the anti-reflection layer is an HfO2 layer with a transmittance of -0.09 dB; and in step 2, when the HfO2 anti-reflection layer is prepared by DC reactive magnetron sputtering, the sputtering time is 2.5 hours. Other aspects are the same as in Example 1.

[0070] Figure 6This is a comparison chart of the transmittance of the broadband high-transmittance tuning ratio optical switch of Example 4 at different temperatures. As can be seen from the figure, the low-temperature transmittance peak is at 6.6μm, the transmittance is -0.46dB at a low temperature of 35℃, and the transmittance is -22.98dB at a high temperature of 70℃, with a transmittance switching ratio of 22.52dB.

[0071] Example 5: This example differs from Example 1 in that: a broadband, high-transmittance, tunable-ratio optical switch is provided. The broadband, high-transmittance, tunable-ratio optical switch comprises a transparent substrate, an anti-reflection layer, and a VO2 layer; the anti-reflection layer is 1000 nm thick; an anti-reflection layer and a 60 nm thick VO2 layer are sequentially provided on both sides of the transparent substrate, from the inside out; the transparent substrate is a Si substrate; the anti-reflection layer is an HfO2 layer with a transmittance of -0.09 dB; and in step 2, when the HfO2 anti-reflection layer is prepared by DC reactive magnetron sputtering, the sputtering time is 3 hours. All other aspects are the same as in Example 1.

[0072] Figure 7 This is a comparison chart of the transmittance of the broadband high-transmittance tuning ratio optical switch of Example 5 at different temperatures. As can be seen from the figure, the low-temperature transmittance peak is at 7μm, the transmittance is -0.87dB at a low temperature of 35°C, and the transmittance is -23.83dB at a high temperature of 70°C, with a transmittance switching ratio of 22.93dB.

[0073] Example 6: This example differs from Example 1 in that: a broadband, high-transmittance, tunable-ratio optical switch is provided. The broadband, high-transmittance, tunable-ratio optical switch comprises a transparent substrate, an anti-reflection layer, and a VO2 layer; the anti-reflection layer is 450 nm thick; an anti-reflection layer and a 60 nm thick VO2 layer are sequentially disposed on one side of the transparent substrate, from the inside out, and an anti-reflection layer is disposed on the other side; the transparent substrate is a silicon substrate; the anti-reflection layer is an HfO2 layer with a transmittance of -0.09 dB; in step 2, the HfO2 anti-reflection layer is prepared by DC reactive magnetron sputtering for 1.5 hours; in step 3, the VO2 layer is prepared on the surface of the anti-reflection layer by DC reactive magnetron sputtering for 30 minutes. All other aspects are the same as in Example 1.

[0074] Figure 8 This is a comparison chart of the transmittance of the broadband high-transmittance tuning ratio optical switch of Example 6 at different temperatures. As can be seen from the figure, the low-temperature transmittance peak is at 4.23μm, the transmittance is -0.4dB at a low temperature of 35℃, and the transmittance is -12.48dB at a high temperature of 70℃, and the transmittance switching ratio is 12.08dB.

[0075] Example 7: This example differs from Example 1 in that: a broadband, high-transmittance, tunable-ratio optical switch is provided. The broadband, high-transmittance, tunable-ratio optical switch comprises a transparent substrate, an anti-reflection layer, and a VO2 layer; the anti-reflection layer is 450 nm thick; an anti-reflection layer and a 120 nm thick VO2 layer are sequentially disposed on one side of the transparent substrate, from the inside out, and an anti-reflection layer is disposed on the other side; the transparent substrate is a silicon substrate; the anti-reflection layer is an HfO2 layer with a transmittance of -0.09 dB; in step 2, the HfO2 anti-reflection layer is prepared by DC reactive magnetron sputtering for 1.5 hours; in step 3, the VO2 layer is prepared on the surface of the anti-reflection layer by DC reactive magnetron sputtering for 60 minutes. All other aspects are the same as in Example 1.

[0076] Figure 9 This is a comparison chart of the transmittance of the broadband high-transmittance tuning ratio optical switch of Example 7 at different temperatures. As can be seen from the figure, the low-temperature transmittance peak is at 5.48μm, the transmittance is -0.96dB at a low temperature of 35℃, and the transmittance is -17.84dB at a high temperature of 70℃, with a transmittance switching ratio of 16.88dB.

[0077] Example 8: This example differs from Example 1 in that: a broadband, high-transmittance, tunable-ratio optical switch is provided. The broadband, high-transmittance, tunable-ratio optical switch comprises a transparent substrate, an anti-reflection layer, and a VO2 layer; the anti-reflection layer is 450 nm thick; an anti-reflection layer and a 220 nm thick VO2 layer are sequentially disposed on one side of the transparent substrate, from the inside out, and an anti-reflection layer is disposed on the other side; the transparent substrate is a silicon substrate; the anti-reflection layer is an HfO2 layer with a transmittance of -0.09 dB; in step 2, the HfO2 anti-reflection layer is prepared by DC reactive magnetron sputtering for 1.5 hours; in step 3, the VO2 layer is prepared on the surface of the anti-reflection layer by DC reactive magnetron sputtering for 90 minutes. All other aspects are the same as in Example 1.

[0078] Figure 10 This is a comparison chart of the transmittance of the broadband high-transmittance tuning ratio optical switch of Example 8 at different temperatures. As can be seen from the figure, the maximum low-temperature transmittance is at 6.31μm, the transmittance is -1.51dB at a low temperature of 35℃, and the transmittance is -23.63dB at a high temperature of 70℃, with a transmittance switching ratio of 22.13dB.

[0079] Example 9: This example differs from Example 1 in that it provides a broadband, high-transmittance, tunable-ratio optical switch comprising a transparent substrate, an anti-reflection layer, and a VO2 layer. The anti-reflection layer is 450 nm thick. The anti-reflection layer and a 290 nm thick VO2 layer are sequentially arranged on one side of the transparent substrate, from the inside out, and the anti-reflection layer is arranged on the other side. The transparent substrate is a silicon substrate. The anti-reflection layer is an HfO2 layer with a transmittance of -0.09 dB. In step 2, the HfO2 anti-reflection layer is prepared by DC reactive magnetron sputtering for 1.5 hours. In step 3, the VO2 layer is prepared on the surface of the anti-reflection layer by DC reactive magnetron sputtering for 120 minutes. All other aspects are the same as in Example 1.

[0080] Figure 11 This is a comparison chart of the transmittance of the broadband high-transmittance tuning ratio optical switch of Example 9 at different temperatures. As can be seen from the figure, the maximum low-temperature transmittance is at 2.7μm, the transmittance is -2.22dB at a low temperature of 35℃, and the transmittance is -40.9dB at a high temperature of 70℃, with a transmittance switching ratio of 38.68dB.

Claims

1. A broadband high transmission tuning ratio optical switch, characterized in that The broadband high transmission tuning ratio optical switch is composed of a transparent substrate, an anti-reflection layer and a VO2 layer; the thickness of the anti-reflection layer is 300nm~1000nm; When both sides of the transparent substrate are provided with an anti-reflection layer and a VO2 layer with a thickness of 20nm to 100nm in sequence from the inside to the outside, the broadband high-transmittance tuning ratio optical switch has a low-temperature transmittance greater than -0.87dB at 35°C, and a maximum transmittance switching ratio of 23.93dB. When an anti-reflection layer and a VO2 layer with a thickness of 20nm to 400nm are sequentially arranged on one side of the transparent substrate from the inside to the outside, and an anti-reflection layer is arranged on the other side, the broadband high-transmittance tuning ratio optical switch has a low-temperature transmittance greater than -2.22dB at 35°C, and the maximum transmittance switching ratio is 38.68dB.

2. A broadband high transmission tuning ratio optical switch according to claim 1, characterized in that The transparent substrate has a transmittance of more than -2.6 dB in the 2.5 μm to 25 μm waveband.

3. The broadband high transmission tuning ratio optical switch according to claim 1, characterized in that The anti-reflection layer has a transmittance of more than -0.09dB in the 2μm~10μm band.

4. The broadband high transmission tuning ratio optical switch according to claim 2, characterized in that The transparent substrate is a Si substrate, a sapphire substrate or a gallium arsenide substrate.

5. The broadband high transmission tuning ratio optical switch according to claim 3, characterized in that The anti-reflection layer is a HfO2 layer, an Al2O3 layer, a ZrO2 layer, a TiO2 layer, a CaF2 layer or a Cr2O3 layer.

6. The method for preparing a broadband high-transmittance tuning ratio optical switch according to claim 1, characterized in that It is carried out in the following steps:

1. Cleaning the substrate: polishing and cleaning the transparent substrate to obtain a pretreated transparent substrate; 2. Preparation of anti-reflection layer: Using magnetron sputtering, electron beam evaporation, pulsed laser deposition or atomic layer deposition, an antireflection layer is formed on both sides of the pretreated transparent substrate; 3. VO2 layer preparation: By using magnetron sputtering, electron beam evaporation, pulsed laser deposition or atomic layer deposition, a VO2 layer is prepared on the surface of one or both sides of the anti-reflection layer to obtain a broadband high transmission tuning ratio optical switch.

7. The method for preparing a broadband high-transmittance tuning ratio optical switch according to claim 6, characterized in that When the anti-reflection layer is a HfO2 layer, the anti-reflection layer is prepared on both sides of the pre-treated transparent substrate by DC reactive magnetron sputtering. Specifically, the steps are as follows: evacuate the vacuum chamber to 1×10 -3 Pa~5×10 -3 Pa, and then heat the pretreated transparent substrate to 200℃~400℃, use metal Hf target as target material, introduce Ar gas, and pre-sputter for 10min~30min under the pre-sputtering pressure of 0.5Pa~1.0Pa, and then introduce O2 gas, and sputter under the conditions of Ar gas flow rate of 75sccm~85sccm, O2 gas flow rate of 4sccm~5sccm, working pressure of 0.5Pa~1Pa and sputtering power of 180W~220W.

8. The method for preparing a broadband high-transmittance tuning ratio optical switch according to claim 6, characterized in that When the anti-reflection layer is a HfO2 layer, the anti-reflection layer is prepared on both sides of the pre-treated transparent substrate by electron beam evaporation. Specifically, the following steps are performed: evacuate the vacuum chamber to 2×10 -3 Pa~5×10 -3 Pa, and then the pretreated transparent substrate is heated to 200℃~400℃, and HfO2 particles are used as film material, and it is prepared under the conditions of working pressure of 0.02Pa~0.05Pa and electron beam current of 100mA~130mA.

9. The method for preparing a broadband high-transmittance tuning ratio optical switch according to claim 6, characterized in that When the anti-reflection layer is a HfO2 layer, the second step is to prepare an anti-reflection layer on both sides of the pre-treated transparent substrate by pulsed laser deposition. Specifically, the steps are as follows: evacuate the vacuum chamber to 1×10 -3 Pa~5×10 -3 Pa, and then the pretreated transparent substrate is heated to 350℃~600℃, hafnium oxide is used as the target, O2 gas is introduced into the vacuum chamber, and sputtering is performed under the conditions of O2 gas flow rate of 1.5sccm~2.5sccm, laser frequency of 5Hz, energy of each pulse of 100mJ~200mJ and deposition pressure of 0.2Pa~0.5Pa.

10. The method for preparing a broadband high-transmittance tuning ratio optical switch according to claim 6, characterized in that Step 3: When using high energy pulse reactive magnetron sputtering to prepare VO2 layer on one or both sides of the antireflection layer, the specific steps are as follows: evacuate the vacuum chamber to 4×10 -4 Pa~6×10 -4 Pa, and then heat the substrate to 450℃~600℃, use metal V target as target material, introduce Ar gas, and pre-sputter for 10min~30min under the pre-sputtering pressure of 0.5Pa~1.0Pa, then introduce O2 gas, and sputter under the conditions of Ar gas flow rate of 75sccm~85sccm, O2 gas flow rate of 1.5sccm~2.2sccm, working pressure of 0.9Pa, sputtering power of 180W~220W, pulse frequency of 400kHz and duty cycle of 1%.

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