CN111083817B - A nonlinear transmitted light processor - Google Patents

Abstract

The invention relates to the technical field of light protection, and discloses a nonlinear transmitted light processor, comprising a substrate, an electric heater and a temperature controller. A phase change film is deposited on one side of the substrate, and another side of the substrate is deposited. The electric heater is arranged on one side, the electric heater is used for heating the substrate, the electric heater is electrically connected with an external power source through the temperature controller, and the temperature controller is used for controlling the substrate The temperature of the bottom is lower than the phase transition temperature of the phase change film, and the difference between the control temperature of the temperature controller and the phase transition temperature is smaller than a set threshold. The optical processor provided by the present invention has the technical effect of fast switching response.

Description

A nonlinear transmitted light processor

technical field

The invention relates to the technical field of light protection, in particular to a nonlinear transmitted light processor.

Background technique

High-sensitivity infrared detectors will have signal saturation under strong light such as laser irradiation, and in severe cases, some pixels of the detector may be permanently damaged. Therefore, preventing strong light from interfering with or destroying infrared detectors is a problem that must be solved in today's detector applications, especially in optoelectronic countermeasure applications. Existing protective measures include improving the anti-glare threshold through reasonable coating design on the optical system and detector, or configuring a nonlinear transmitted light element in front of the infrared detector to block or limit the passage of strong light, but still maintain weak light. pass. There are two main types of nonlinear transmitted light components, one is thin-film optical switching elements based on thermally induced phase change, such as VO ₂ thin-film optical switches, and the other is based on nonlinear optical absorption or scattering effects that lead to saturation of transmitted light. Coated elements, such as graphene-based coatings. Among them, although the nonlinear transmission elements based on phase change films have the characteristics of simple structure and intelligent response, their optical switching response characteristics are relatively simple and the response time is long.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above-mentioned technical deficiencies and provide a nonlinear transmitted light processor, which solves the technical problem that the optical switch in the prior art has a long response time and cannot well protect the detector.

In order to achieve the above technical purpose, the technical solution of the present invention provides a nonlinear transmitted light processor, including a substrate, an electric heater and a temperature controller, a phase change film is deposited on one side of the substrate, and the substrate is The electric heater is arranged on the other side of the substrate, and the electric heater is used to heat the substrate, and the electric heater is electrically connected to an external power supply through the temperature controller, and the temperature controller is used to control the The temperature of the substrate is lower than the phase transition temperature of the phase change film.

Compared with the prior art, the beneficial effects of the present invention include: the present invention configures an electric heater on the substrate, the electric heater heats the substrate, and the substrate transfers heat to the phase change film. The heating temperature of the electric heater is controlled by the temperature controller, and the substrate and the phase change film are preheated to a temperature value close to the phase change temperature of the phase change film but lower than the phase change temperature of the phase change film, so as to reduce the phase change of the phase change film. Therefore, the switching time of the phase change can be greatly shortened, the timely response capability of the optical processor to strong light irradiation can be improved, and the response time can be reduced. When the laser strikes, it only takes a short time and a small optical power to make the phase change film. When applied to the protection of the detector, it can greatly shorten the time that the detector is irradiated by strong light, reduce the power irradiated by the strong light, reduce the interference of the strong light, and better protect the detector. The invention integrates the electric heater on the passive nonlinear transmission light element, so that it has the adjustable performance of the phase transition threshold, and because the phase transition threshold is reduced, the strong light warning time is shortened, and the detection can be better protected. device.

Description of drawings

1 is a top view of an embodiment of a nonlinear transmitted light processor provided by the present invention;

Fig. 2 is a sectional view at A-A in Fig. 1;

3 is a front view of an embodiment of a nonlinear transmitted light processor provided by the present invention;

Figure 4 is a schematic diagram of typical curves and associated power values involved in the present invention.

Reference number:

1. Substrate, 2. Electric heater, 21. Heating electrode, 22. Connecting electrode, 3. Phase change film, 31. Metal electrode, 4. Bias power supply, 5. Signal acquisition circuit.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

Example 1

As shown in FIG. 1 and FIG. 2, Embodiment 1 of the present invention provides a nonlinear transmitted light processor, hereinafter referred to as the optical processor, including a substrate 1, an electric heater 2 and a temperature controller. The substrate 1 A phase change film 3 is deposited on one side of the substrate 1, and the electric heater 2 is arranged on the other side of the substrate 1, and the electric heater 2 is used to heat the substrate 1. The electric heater 2 The temperature controller is electrically connected to an external power source, and the temperature controller is used to control the temperature of the substrate 1 to be lower than the phase change temperature of the phase change film 3, and the control temperature of the temperature controller is the same as that of the temperature controller. The difference in phase transition temperature is less than the set threshold.

The working principle of the present invention is as follows: when the phase change film 3 on the large-area substrate 1 is irradiated by strong light IR, a thermally reversible phase change is generated mainly through the effect of radiation heating. Before and after the phase change, the infrared transmittance of the phase change film 3 changes greatly, from a high transparency state at low temperature to a low transmittance state at high temperature, so this nonlinear change is also called a phase change optical switch . When irradiated by strong light IR, since the radiative heating of light requires a certain amount of time to accumulate, the switching action time generated by the thermally induced phase transition can generally only reach the order of ms. In the embodiment of the present invention, an electric heater 2 is configured on the substrate 1, and the electric heater 2 preheats the substrate 1 to a temperature value close to the phase transition temperature, which can greatly shorten the phase transition switching time and reduce the generation of Optical power threshold for phase transition. When applied to the protection of the detector, the time that the detector is irradiated by strong light can be greatly shortened, and the power irradiated by the strong light can be reduced. In addition, the phase change film 3 also has a phase change threshold, that is, the optical power required to generate the phase change. Generally, when there is no preheating, the phase change threshold of the phase change film 3 is relatively high, and the strong light IR undergoes a phase change. The peak value of the transmitted light power behind the film 3 is higher than the signal saturation threshold of the detector, so even if the phase change film 3 is used, the detector signal may be saturated for a period of time, resulting in the detector not working effectively during this period of time. However, in this embodiment, the electric heater 2 is provided to preheat the substrate 1 and the phase change film 3 to a certain temperature, which can reduce the phase change threshold of the phase change film 3 and also reduce the optical power passing through the phase change film 3. There are It helps the light processor to respond to the strong light irradiation in time and reduces the strong light response time, which is very beneficial to reduce the interference of the strong light and protect the detector.

FIG. 4 presents a schematic diagram of the optical power distribution involving the intense light irradiation, the phase change film 3 and the light received by the detector. _PL is the laser peak power, curve 1 is the schematic curve of the strong light IR irradiation pulse; curve 2 is the transmitted light power curve of the VO ₂ phase change film 3 without preheating, and curve 3 is the VO ₂ phase change film 3 preheated The transmitted light power curve of , P _VO2 is the unpreheated transmission light peak power of the VO ₂ phase change film 3, P _VO2 ^′ is the preheated transmission light peak power of the VO ₂ phase change film 3; P _s,max is the normal condition The maximum optical power value of the signal light received by the lower detector, P _s,th is the optical power threshold value of the signal light received by the detector when the signal is saturated, P _d,th is the light received by the detector when it is damaged by strong light irradiation power threshold. It can be seen from FIG. 4 that after preheating, the peak power of the transmitted light of the phase change film 3 decreases, the phase change threshold decreases, and the phase change reaction is faster.

The present invention integrates the electric heater 2 on the passive nonlinear transmissive light element, and combines with the temperature controller to form an active light processor that can be actively preheated, so that it has the phase transition threshold adjustability, thereby reducing the The phase transition threshold shortens the calorific value phase transition reaction time and can better protect the detector.

Preferably, the electric heater 2 includes a heating electrode 21 and two connecting electrodes 22, the heating electrode 21 and the two connecting electrodes 22 are both disposed on the substrate 1, and one end of the heating electrode 21 is electrically connected to one of the connection electrodes 22, the other end of the heating electrode 21 is electrically connected to the other connection electrode 22, and the two connection electrodes 22 are respectively electrically connected to an external power source through the temperature control device, Realize the function of heating and temperature control.

Preferably, as shown in FIG. 1 , the heating electrode 21 is serpentine.

The serpentine heating electrodes 21 can be evenly distributed on the substrate 1 , which is beneficial to the uniform heating of the substrate 1 and the phase change film 3 . The resistance range of the heating electrode 21 can be set at 100-300Ω.

Preferably, the heating electrode 21 is an infrared transparent electrode. In order to ensure the transparency to the mid-wave infrared band, the heating electrode 21 in this embodiment selects an infrared transparent electrode, that is, the heating electrode 21 made of a material that transmits light in the infrared band. The infrared transparent electrode can be realized by a transparent conductive metal oxide film. Such as doped In ₂ O ₃ , NiCo ₂ O ₄ , LiCo ₂ O ₄ and other thin films.

Preferably, as shown in FIG. 3 , the optical processor further includes a bias power supply 4 and a signal acquisition circuit 5 , the bias power supply 4 is electrically connected to the phase change film 3 , and the signal acquisition circuit 5 is electrically connected to the The phase change film 3 is electrically connected and used to measure the resistance change of the phase change film 3 .

In this preferred embodiment, the signal acquisition circuit 5 is used to output the early warning signal of the strong light in time, so as to realize the capability of outputting the early warning signal without waiting for the completion of the phase change. Specifically, a pair of metal electrodes 31 are deposited on opposite sides of the phase change film 3 , the phase change film 3 is connected to the bias power supply 4 through the metal electrodes 31 , and the bias power supply 4 provides a bias voltage for the phase change film 3 , while the phase change film 3 is The film 3 is electrically connected to the external signal acquisition circuit 5 through the metal electrode 31 , and the signal acquisition circuit 5 is used to measure the voltage change caused by the resistance change of the phase change film 3 . The signal acquisition circuit 5 can be implemented by using a voltage divider measurement circuit, as long as the measurement of the resistance change can be realized. During the interaction between the strong light and the phase change film 3, as the temperature increases, the resistance of the phase change film 3 is continuously decreasing, and the voltage signal obtained by the signal acquisition circuit 5 is also changing, but the transmitted strong light Power is still growing. When the transmitted power is significantly higher than the maximum power value P _s,max of normal light, but has not yet reached the optical power threshold P _s,th at saturation, the signal acquisition circuit 5 can compare the real-time signal with the preset signal value , the judgment result of the appearance of strong light can be obtained, so the early warning signal of the appearance of strong light can be quickly sent to the detector or other devices, so that the detector or other devices can take preventive measures or perform certain actions in time. On the other hand, based on the pre-scaled data, it is also possible to judge whether the temperature value of the substrate 1 reaches or exceeds the set value through the change of the voltage.

Preferably, the phase change film 3 has multiple layers, and the multiple layers of the phase change films 3 are sequentially stacked and deposited on the substrate 1 , and the multiple layers of the phase change films 3 are respectively phase change films 3 of different materials.

The phase change film 3 with a multi-layer structure is used to further improve the infrared transmittance and at the same time improve the anti-strong light damage threshold.

Preferably, the substrate 1 is a sapphire substrate 1 .

In this embodiment, a sapphire substrate 1 made of sapphire material is used, and other substrates 1, such as a mid-wave infrared transparent substrate 1 such as silicon, germanium, and ZnSe, may also be used.

Preferably, the phase change film 3 is a VO ₂ phase change film 3 .

In this embodiment, a VO ₂ phase change film 3 made of vanadium dioxide is used. Specifically, a square or rectangular VO ₂ phase change film 3 with a thickness of 50-200 nm is deposited on the first surface of the sapphire substrate 1 . The phase change film ₃ can also be a film system based on a VO2 film, the film system includes a surface antireflection layer, such as a _SiO2 layer, and also includes a buffer layer between the VO2 film and the substrate ₁ , such as _Al2 O ₃ layers.

The specific embodiments of the present invention described above do not limit the protection scope of the present invention. Any other corresponding changes and modifications made according to the technical concept of the present invention shall be included in the protection scope of the claims of the present invention.

Claims (6)

1. a nonlinear transmitted light processor, is characterized in that, comprises substrate, electric heater and temperature controller, and phase change film is deposited on one side of described substrate, and the other side of described substrate is provided with The electric heater is used for heating the substrate, and the electric heater is electrically connected with an external power source through the temperature controller, and the temperature controller is used for controlling the temperature of the substrate to be low At the phase transition temperature of the phase change film, the difference between the control temperature of the temperature controller and the phase transition temperature is less than a set threshold; Wherein, the nonlinear transmitted light processor further includes a bias power supply and a signal acquisition circuit, the bias power supply is electrically connected with the phase change film, the signal acquisition circuit is electrically connected with the phase change film, and is connected with the phase change film. In order to measure the resistance change of the phase change film, the signal acquisition circuit compares the real-time signal with the preset signal value to determine whether the detector is currently interfered by strong light, and when the detector encounters the interference of strong light, an early warning signal is issued; The phase change film has multiple layers, and the multiple layers of the phase change films are sequentially stacked and deposited on the substrate, and the multiple layers of the phase change films are phase change films of different materials respectively. 2 . The nonlinear transmitted light processor according to claim 1 , wherein the electric heater comprises a heating electrode and two connection electrodes, and the heating electrode and the two connection electrodes are both disposed on the On the substrate, one end of the heating electrode is electrically connected to one of the connection electrodes, the other end of the heating electrode is electrically connected to the other connection electrode, and the two connection electrodes pass through the temperature control device respectively Electrically connected to an external power source. 3 . The nonlinear transmitted light processor according to claim 2 , wherein the heating electrode is serpentine. 4 . 4. The nonlinear transmitted light processor according to claim 2, wherein the heating electrode is an infrared transparent electrode. 5. The nonlinear transmitted light processor of claim 1, wherein the substrate is a sapphire substrate. 6 . The nonlinear transmitted light processor of claim 1 , wherein the phase change film is a VO ₂ phase change film. 7 .

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