A light wave complex amplitude modulation device

Abstract

The present invention discloses a light wave complex amplitude modulation device, which at least includes a first modulation layer, a second modulation layer and a heat insulation layer located therebetween. The light beam modulated by the first modulation pixel unit is projected through a unique heat insulation pixel unit and is only projected to the unique second modulation pixel unit. By setting a unique heat insulation pixel unit for precise projection, the front and back two-stage modulation of two complex amplitude modulation pixels is realized. Two-stage dynamic complex amplitude modulation is an ideal technical path with optimal performance in all aspects and greatly simplified structure. It breaks many shackles such as low amplitude and phase modulation levels, mutual interference, and complex preparation process. It can realize independent and multi-order amplitude modulation and phase modulation complex amplitude complete information reconstruction, and the amplitude and phase modulation processes are separated in time and space, thereby improving the performance such as resolution, amplitude distribution uniformity, accuracy and signal-to-noise ratio, so as to complete the dynamic switching of images and improve the quality of reconstructed images.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and in particular to a light wave complex amplitude modulation device. Background Art

[0002] Complex amplitude modulation technology records and reconstructs all wave information of a target and object by modulating the complex amplitude information of light waves. It has important application prospects in the fields of holographic technology and spatial light modulators, and has been widely used in 3D display, interferometry, military reconnaissance and surveillance, information storage, medical testing and many other national defense and military and real life.

[0003] Static complex amplitude modulation technology is a relatively common complex amplitude modulation technology. Its modulation effect is fixed when the modulation device structure is generated and cannot be adjusted. It can only generate a certain reconstructed image. Dynamic complex amplitude modulation can dynamically adjust the light wave information without changing the device structure and output a dynamically changing sequence of images. In the prior art, dynamic complex amplitude modulation is based on the excitation signal on the modulation unit structure to change its refractive index and extinction coefficient, thereby modulating the amplitude and phase values ​​of the light wave.

[0004] Since the amplitude modulation and phase modulation effects interfere with each other, a dynamic complex amplitude modulation unit (single-factor dynamic modulation) modulated by an electrical excitation often cannot obtain the required amplitude and phase combination, that is, the required complex amplitude value cannot be obtained.

[0005] Optimizing the modulation unit structure to achieve dynamic modulation is currently the focus of researchers. For example, increasing the size of the dynamic complex amplitude modulation unit can achieve multi-order amplitude and phase changes in the unit structure to a certain extent, thereby more finely modulating the complex amplitude value of the light wave. However, the increase in unit size leads to a decrease in the resolution of the entire device, which is contrary to the current trend of high resolution and high precision in complex amplitude modulation technology.

[0006] After the first modulation layer performs pixel-modulation on the phase of the light wave, the transmission direction of the light waves modulated by different units changes, which inevitably causes the problem of optical information crosstalk between the two modulation layers. In order to solve this problem, the existing technology limits the incident light to parallel light and the first modulation to pure amplitude modulation, which only changes the intensity of the light but does not change the phase of the light. That is, the transmission direction of the light beam remains unchanged after pure amplitude modulation, and after modulation by the amplitude modulator, the outgoing light still has the modulation effect of parallel light. However, the pure amplitude modulation unit is complex in design, large in unit size, and high in manufacturing cost, which greatly reduces the feasibility of this solution. Summary of the invention

[0007] The purpose of the present invention is to provide a lightwave complex amplitude modulation device. The present invention does not rely on the dynamic modulation effect of the modulation unit itself, but adopts two modulation units, combined with two easily controllable independent signal excitations, and greatly improves the controllability of complex amplitude modulation through second-order dynamic regulation.

[0008] Furthermore, the second-order dynamic regulation of the modulation unit inevitably has thermal crosstalk. In the initial scheme of the present invention, high-precision modulation cannot be achieved through the conventional thermal insulation layer. After in-depth research by the team, we found that the optical information crosstalk problem caused by the diffraction of the light beam at the interface between the first modulation layer and the thermal insulation layer and the optical path difference factor of the thermal insulation layer are important factors that lead to the imperfection of the initial scheme of the present invention. So far, no prior art has disclosed the above factors and related factors, and no prior art has linked the above factors and related factors to complex amplitude modulation.

[0009] Specifically, the present invention adopts the following technical solution: at least one first modulation layer and one second modulation layer, the first modulation layer includes one or more first modulation pixel units, and the second modulation layer includes one or more second modulation pixel units; the light beam modulated by the first modulation pixel unit is projected through a unique thermal insulation pixel unit and is only projected to the unique second modulation pixel unit for secondary modulation; when the number of the thermal insulation pixel units is two or more, the optical path of each thermal insulation pixel unit is the same.

[0010] In some preferred embodiments, the first modulation pixel unit directly adopts an amplitude modulation unit, and the second modulation unit directly adopts a phase modulation unit; or the first modulation pixel unit directly adopts a phase modulation unit, and the second modulation unit directly adopts an amplitude modulation unit. The aforementioned amplitude modulation unit is a pixel modulation unit that focuses on regulating the amplitude, and the phase modulation unit is a pixel modulation unit that focuses on regulating the phase. For example, the amplitude modulation unit adopted is: under the control of electrical excitation, the modulation of the amplitude of the light wave is uniform and multi-order in the range of 0-1, and the change in the phase of the light wave is within ±π / 5; the phase modulation unit is: under the control of electrical excitation, the modulation of the phase of the light wave is uniform and multi-order in the range of 0-2π, and the change in the amplitude of the light wave is stable, and the fluctuation value is within 10%.

[0011] Furthermore, the first modulation pixel unit and the second modulation pixel unit change their optical properties through additionally introduced signal excitation (electrical excitation, optical excitation, etc.) to achieve modulation of the light beam.

[0012] It should be noted that the optical properties of the modulated pixel unit refer to the various properties exhibited by the modulated pixel unit when absorbing, reflecting, refracting, scattering and diffracting light. When the excitation signal is activated (for example, the phase change material is activated by the electrical signal), the optical properties change, and the various properties exhibited by the absorption, reflection, refraction, scattering and diffraction of light change, and the corresponding amplitude attenuation ratio and phase shift also change. Therefore, materials such as phase change materials and liquid crystal materials that can achieve optical property regulation can be used as the modulated pixel unit of the present application.

[0013] That is, after a stimulus signal is applied to a modulated pixel unit, its optical properties such as refractive index and extinction coefficient change, and the corresponding amplitude attenuation ratio and phase shift also change (e.g. Figure 4 ). Those skilled in the art can obtain the required excitation signal from the required amplitude attenuation ratio and phase offset by reverse calculation, thereby achieving higher precision modulation. The present invention further modulates the excitation signal of the first modulation pixel unit and the second modulation pixel unit by the following method: according to the complex amplitude information A of the target light wave at the nth pixel unit n (t,λ) and P n (t,λ), remove the initial complex amplitude information of the input light wave at the nth pixel unit and The phase modulation variation and amplitude modulation variation of the nth pixel unit are obtained, and the amplitude attenuation ratio and phase offset of the nth first modulation pixel unit and the nth second modulation pixel unit are obtained by decoupling, so that the optical properties such as the refractive index and extinction coefficient of the nth first modulation pixel unit and the nth second modulation pixel unit can be obtained, and finally the excitation signal applied to the nth first modulation pixel unit and the nth second modulation pixel unit can be obtained. and After a modulated pixel unit receives an excitation signal, its optical properties such as refractive index and extinction coefficient can be tested by simple means, and even the relationship function between the excitation signal and the optical properties can be obtained by simple testing (such as Figure 4 ). The art can obtain the required excitation signal by reverse calculation based on this function.

[0014] The principle of decoupling is as follows: the phase information of the light wave in the nth pixel unit is modulated by the nth first modulation pixel unit and the nth second modulation pixel unit at the same time, and the phase difference between the target light wave and the incident light wave of the nth pixel unit is equal to the sum of the phase modulation amount of the nth first modulation pixel unit and the phase modulation amount of the nth second modulation pixel unit; the amplitude attenuation ratio of the target light wave and the incident light wave of the nth pixel modulation unit is modulated by the nth first modulation pixel unit and the nth second modulation pixel unit at the same time, and the amplitude attenuation ratio of the target light wave to the incident light wave is equal to the product of the amplitude modulation amount of the nth first modulation pixel unit and the amplitude modulation amount after the nth second modulation pixel unit.

[0015] Furthermore, the first modulation pixel unit, the second modulation pixel unit and the thermal isolation pixel unit respectively form arrays. In the three arrays, the first modulation pixel unit, the second modulation pixel unit and the thermal isolation pixel unit have a unique one-to-one correspondence.

[0016] Furthermore, the heat-insulating pixel unit is a light-guiding structure (including but not limited to light-guiding fiber, photonic crystal, grating), which is configured to guide the light beam after the primary modulation to the second modulation pixel unit for secondary modulation. The heat-insulating performance of such a light-guiding structure can be achieved by selecting appropriate materials or designing appropriate structures, which is not described in detail in this application.

[0017] The beneficial effect of the present invention is that the present invention realizes the front and rear two-stage modulation of two complex amplitude modulation pixels by setting a unique heat-insulating pixel unit for precise projection. Two-stage dynamic complex amplitude modulation is an ideal technical path with the best performance in all aspects and greatly simplified structure. It also realizes the functions of dynamic modulation of the image, two-stage independent modulation of phase and amplitude, and can obtain high-quality wavefront reconstruction of real holographic dynamic images. It breaks the many shackles of low amplitude and phase modulation levels, mutual interference, and complex preparation process, and can realize independent and multi-level amplitude modulation and phase modulation of complex amplitude complete information reconstruction, and separate the amplitude and phase modulation processes in time and space, thereby improving the performance of resolution, amplitude distribution uniformity, accuracy and signal-to-noise ratio, so as to complete the dynamic switching of images and improve the quality of reconstructed images. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The first modulation pixel unit in Embodiment 1 adopts a digital metasurface structure based on phase change material and different crystalline / amorphous combinations;

[0019] Figure 2 yes Figure 1 The complex amplitude modulation of the first modulated pixel unit when different electrical excitation intensities are applied, Figure 2A is the adjustment amount of the amplitude with different electric excitation intensity, Figure 2 B is the amount of adjustment of the phase with different electrical excitation intensity;

[0020] Figure 3 The second modulation pixel unit in Embodiment 1 adopts a digital metasurface structure based on phase change material and different crystalline / amorphous combinations;

[0021] Figure 4 yes Figure 3 The complex amplitude modulation of the second modulation pixel unit when different electrical excitation intensities are applied, Figure 4 A is the adjustment amount of different phases with different electric excitation intensity, Figure 4 B is the adjustment amount with different amplitudes depending on the intensity of electrical excitation;

[0022] Figure 5 It is the complex amplitude modulation device structure in embodiments 2 and 3;

[0023] Figure 6 This is the unit structure adopted by the first modulation pixel unit and the second modulation pixel unit in embodiments 2 and 3;

[0024] Figure 7 It is the heat-insulating intermediate layer unit structure used in Examples 2 and 3;

[0025] Figure 8 It is the simulation unit structure used in Examples 2 and 3;

[0026] Fig. 9 This is the simulation result of the two-stage complex amplitude modulation in Example 2 using the heat-insulating intermediate layer and without using the decoupling algorithm. Fig. 9 A is the amplitude distribution diagram of the light wave output plane, Fig. 9 B is the phase value distribution diagram of the light wave output plane;

[0027] Fig.10 It is a simulation unit structure in Example 2 without using a heat-insulating intermediate layer and without using a decoupling algorithm;

[0028] Fig.11 This is the simulation result of the two-stage complex amplitude modulation in Example 2 without using the thermal insulation intermediate layer and the decoupling algorithm. Fig.11 A is the amplitude distribution diagram of the light wave output plane, Fig.11 B is the phase value distribution diagram of the light wave output plane;

[0029] Fig.12 is the simulation result of the two-stage complex amplitude modulation using the heat-insulating intermediate layer and the decoupling algorithm in Example 3, Fig.12 A is the amplitude distribution diagram of the light wave output plane, Fig.12 B is the phase value distribution diagram of the light wave output plane. DETAILED DESCRIPTION

[0030] Example 1

[0031] This embodiment takes a two-stage modulation pixel unit as an example to illustrate the unique advantage of two-stage regulation in improving the accuracy of complex amplitude dynamic modulation.

[0032] Figure 1 It is the first modulated pixel unit of this embodiment, which adopts a digital metasurface unit structure based on phase change materials. The substrate is a 1600nm×1600nm Si material, on which are placed four 800nm ​​high GSST (Ge2Sb2Se4Te) cylinders of different sizes, with radii of d1=425nm, d2=220nm, d3=205nm, and d4=230nm, respectively. There is an electric excitation source under each GSST cylinder, which can independently control the crystalline / amorphous state of each GSST material. The communication wavelength tested is 1550nm. Under the different crystalline / amorphous combinations of the four GSST materials, the modulation amount of the amplitude modulated digital metasurface unit (first modulated pixel unit) on the amplitude and phase of the light wave in the area is as follows: Figure 2 A and 2B, and the data are shown in Table 1 (ABCD represents the GSST cylinders with diameters of d1, d2, d3 and d4 respectively):

[0033] Table 1: Modulation amount of light wave amplitude and phase by the amplitude modulation digital metasurface unit (first modulation pixel unit) in Example 1

[0034]

[0035] Figure 3 It is the second modulation pixel unit made in this embodiment, which adopts a digital metasurface structure based on phase change material. The substrate is a 1600nm×1600nm Si material, on which are placed four 800nm ​​high GSST (Ge2Sb2Se4Te) cylinders of different sizes, with radii of D1=470nm, D2=435nm, D3=410nm, and D4=365nm. There is an electric excitation source under each GSST cylinder, which can independently control the crystalline / amorphous state of each GSST material. The communication wavelength of each test is 1550nm. Under the different crystalline / amorphous combinations of the four GSST materials, the modulation amount of the amplitude and phase of the light wave in the region by the phase modulation digital metasurface unit (second modulation pixel unit) is as follows: Figure 4 A and 4B, and the data are shown in Table 2 (WXYZ represents the GSST cylinders with diameters of D1, D2, D3 and D4 respectively):

[0036] Table 2: Modulation amount of light wave amplitude and phase by the phase modulation digital metasurface unit (second modulation pixel unit) in Example 1

[0037]

[0038] A single first modulation pixel unit has eight different amplitude modulation amounts and three different phase modulation amount changes, with a total of eight different complex amplitude values; a single second modulation pixel unit has eight complex amplitude values ​​with different amplitudes and phases. After combination, the range of complex amplitude modulation that can be modulated is expanded to 8×8. Assuming that the incident light is a plane wave perpendicular to the device, with a phase of 0 and an amplitude of 1, all the amplitude values ​​of the light waves obtained by all different crystalline / amorphous combinations of the first modulation pixel unit and the second modulation pixel unit are shown in Table 3:

[0039] Table 3: All light wave amplitude modulation values ​​obtained for different crystalline / amorphous combinations

[0040] Amplitude value BCD / A BD / AC CD / AB B / ACD / ABCD AB / CD AC / BD A / BCD XYZ / W 0.012 0.016 0.0096 0.0088 0.0088 0.0076 0.0008 0.0072 WXY / Z 0.108 0.144 0.0864 0.0792 0.0792 0.0684 0.0072 0.0648 WX / YZ 0.132 0.176 0.1056 0.0968 0.0968 0.0836 0.0088 0.0792 W / XYZ 0.216 0.288 0.1728 0.1584 0.1584 0.1368 0.0144 0.1296 / WXYZ 0.312 0.416 0.2496 0.2288 0.2288 0.1976 0.0208 0.1872 Z / WXY 0.384 0.512 0.3072 0.2816 0.2816 0.2432 0.0256 0.2304 Y / WXZ 0.432 0.576 0.3456 0.3168 0.3168 0.2736 0.0288 0.2592 YZ / WX 0.492 0.656 0.3936 0.3608 0.3608 0.3116 0.0328 0.2952

[0041] All phase values ​​of the light waves obtained by all different crystalline / amorphous combinations of the amplitude dynamic modulation unit and the phase dynamic modulation unit are shown in Table 4 and Table 3:

[0042] Table 4: All light wave phase modulation values ​​obtained for different crystalline / amorphous combinations

[0043]

[0044] From the above, it can be seen that by changing the excitation mode of the first modulation pixel unit and the second modulation pixel unit and selecting different crystalline / amorphous combinations, the original eight amplitude-phase combinations of primary modulation can be expanded to 64 amplitude-phase modulation combinations, greatly improving the accuracy of light wave complex amplitude modulation.

[0045] Those skilled in the art should know that this embodiment can be equivalently replaced by other PCM microstructures, and can also achieve the high-precision technical effect of this embodiment, such as rod-shaped, V-shaped, cross-shaped, C-shaped structures, etc., with a thickness in the range of 50-600nm. The PCM microstructures are arranged and combined, and each microstructure has a separate electrical excitation source, which can realize the mutual transformation between the crystalline state and the amorphous state of each microstructure, so that the optical properties of the first modulated pixel unit change, thereby realizing the change of the phase modulation amount and the amplitude modulation amount of the entire digital metasurface unit (modulated pixel unit). In addition, several PCM microstructures of different shapes can be placed on a substrate to form a digital metasurface unit, and each microstructure is electrically excited to produce changes in the refractive index and extinction coefficient under different phase combinations, thereby realizing the change of the amplitude attenuation ratio and phase offset of the digital metasurface unit, and encoding each change value, which can realize nearly continuous multi-order phase changes in the full range of [0,2π] and nearly continuous multi-order amplitude changes in the full range of [0,1].

[0046] In the present application, each modulation pixel unit on the first modulation layer and the second modulation layer is controlled by an independent signal excitation source, and the units do not interfere with each other. Based on this embodiment, a person skilled in the art can foresee that the present application, based on the secondary modulation of the first modulation layer and the second modulation layer, can also greatly improve the modulation accuracy.

[0047] Example 2

[0048] like Figure 5 Figure 5 As shown, this embodiment provides a complex amplitude dynamic modulator, including a first modulation layer and a second modulation layer, and a thermal insulation layer located therebetween, wherein the first modulation layer has first modulation pixel units M1~M3, the second modulation layer has second modulation pixel units N1~N3, the thermal insulation layer has thermal insulation pixel units I1~I3, the first modulation pixel units, the second modulation pixel units, and the thermal insulation pixel units each form an array, and each unit corresponds one to one.

[0049] After the local light wave is modulated once by the first modulation pixel unit M1 of the first modulation layer of the device, it is constrained by the thermal insulation pixel unit I1 with a light guiding structure adjacent to the first modulation pixel unit M1, so that all light beams modulated by the first modulation pixel unit M1 can be completely and accurately projected and only projected to the second modulation pixel unit N1 of the second modulation layer for secondary modulation; similarly, the specific area light beam that is modulated once in the first modulation pixel unit M2 of the first modulation layer of the device can be projected and only projected to the second modulation pixel unit N2 of the second modulation layer for secondary modulation after being guided by the thermal insulation pixel unit I2 adjacent to the first modulation pixel unit M2.

[0050] In this embodiment, the first modulation pixel unit and the second modulation pixel unit can be used as follows Figure 6 The structure based on phase change material shown in the figure, in which the phase change material is GST material, with a size of 600nm×600nm×200nm, and transparent electrode material layers on the upper and lower sides. GST material will produce a variety of intermediate states with different crystallization degrees under the stimulation of different electric pulse intensities, and the complex refractive index will change in multiple orders, thereby realizing multiple orders of amplitude modulation and phase modulation.

[0051] In this embodiment, the heat-insulating pixel unit adopts Figure 7 The micrometer-scale optical fiber structure shown has a cladding refractive index greater than the core refractive index, which envelops the transmission light beam, so that the light wave modulated by the first modulation pixel unit is completely and accurately projected onto the only second modulation pixel unit. In order to ensure accuracy, the thickness, structure, material and other parameters of the thermal insulation pixel unit can be fine-tuned to ensure that the optical path difference of each thermal insulation pixel unit is consistent.

[0052] This embodiment is simulated and a simulation model of the heat insulation intermediate layer is configured as follows Figure 8 As shown, the excitation signal applied to the first modulation pixel unit and the second modulation pixel unit is changed, thereby changing the optical properties of the two modulation units respectively. The input light wave of this example is Target light wave The amplitude value of the output plane center light wave is about 0.021, with a deviation of 34.4%; the phase value is about 0.608π, with a deviation of 21.6% from the target phase value. The simulation results are as follows: Fig. 9 shown.

[0053] Fig.10 It is a two-stage complex amplitude control scheme without an intermediate insulation layer. Figure 8 The same electrical excitation. The amplitude of the output plane center light wave is about 0.025, with a deviation of 21.9%; the phase value is about 0.56π, with a deviation of 12% from the target phase value; the simulation results are as follows Fig.11 shown.

[0054] It can be seen from the above embodiments that the intermediate heat insulating layer can greatly improve the accuracy of light wave complex amplitude modulation.

[0055] Example 3

[0056] In this embodiment, the first modulation pixel unit and the second modulation pixel unit can be used as follows Figure 6The structure based on phase change material shown in the figure, in which the phase change material is GST material, with a size of 600nm×600nm×200nm, and transparent electrode material layers on the upper and lower sides. GST material will produce a variety of intermediate states with different crystallization degrees under the stimulation of different electric pulse intensities, and the refractive index and extinction coefficient will undergo multi-order changes, thereby realizing multi-order amplitude modulation and phase modulation.

[0057] In this embodiment, the heat-insulating pixel unit can be used as follows: Figure 7 The micrometer-scale optical fiber structure shown has a cladding refractive index greater than the core refractive index, which envelops the transmission light beam, so that the light wave modulated by the first modulation pixel unit is completely and accurately projected onto the only second modulation pixel unit. In order to ensure accuracy, the thickness, structure, material and other parameters of the thermal insulation pixel unit can be fine-tuned to ensure that the optical path difference of each thermal insulation pixel unit is consistent.

[0058] On the basis of improving the precision of the two-stage modulation in Embodiment 2, this embodiment further adopts a decoupling algorithm to optimize the excitation signal, including the electrical excitation of each first modulated pixel unit and the electrical excitation of each second modulated pixel unit. M1 and the electrical excitation U of the second modulation pixel unit N1 N1 The decoupling process is as follows:

[0059]

[0060] Where A and P are the amplitude and phase of the target light wave, respectively; A0 and P0 are the amplitude and phase of the incident light wave, respectively; A M1 and P M1 A represents the modulation of the light wave amplitude and the shift of the light wave phase caused by the first modulation pixel unit M1; N1 and P N1 Indicates the modulation of the light wave amplitude and the shift of the light wave phase by the second modulation pixel unit N1; satisfies:

[0061] A M1 =f MA (U M1 )

[0062] P M1 =f MP (U M1 )

[0063] P N1 =f NP (U N1 )

[0064] A N1 =f NA (UN1 )

[0065] f MA (U M1 ) is the amplitude modulation function of the first modulation pixel unit, indicating that the first modulation pixel unit M1 is M1 The amplitude attenuation ratio of the light wave generated under electrical excitation. NA (U N1 ) is the amplitude modulation function of the second modulation pixel unit, indicating that the second modulation pixel unit N1 is N1 The amplitude attenuation ratio of the light wave generated under electrical excitation. MP (U M1 ) is the phase modulation function of the first modulation pixel unit, indicating that the first modulation pixel unit M1 is at U M1 The phase shift of the light wave generated by the electrical excitation. NP (U N1 ) The phase modulation function of the second modulation pixel unit, indicating that the second modulation pixel unit N1 is in U N1 The phase shift of the light wave generated by the electrical excitation is

[0066] By controlling parameters such as the width and number of electric pulses, the electric excitation signal changes the signal excitation intensity, and inputs it into the first modulation pixel unit and the second modulation pixel unit based on the phase change material respectively, so that the phase change material undergoes a phase change and the optical properties of the device change, thereby realizing independent dynamic modulation of the amplitude and phase information.

[0067] This embodiment is simulated, and the simulation model is as follows Figure 8 As shown, the signal excitation intensity applied to the first modulation pixel unit and the second modulation pixel unit is changed, thereby changing the optical properties of the two modulation units respectively, and then controlling the amplitude modulation amount and phase modulation amount of the first modulation pixel unit and the second modulation pixel unit respectively.

[0068] The input light wave of this embodiment is the same as that of embodiment 2. Target light wave After optimizing the excitation signal using the above decoupling algorithm, the simulation results are as follows: the amplitude of the light wave at the center of the output plane is The deviation from the target amplitude is 3.1%; the light wave phase value at the center of the output plane is The deviation from the target amplitude is 2%, such as Fig.12 shown.

[0069] Compared with the simulation results of Example 2 which includes an intermediate layer and does not use the decoupling algorithm, the error between the simulation results of this embodiment and the expected complex amplitude value is greatly reduced. It can be seen from the above embodiments that the decoupling algorithm can greatly improve the accuracy of light wave complex amplitude modulation and the degree of freedom of modulation.

[0070] It should be noted in this embodiment that the structures of the two layers of modulated pixel units do not have to be exactly the same. Those skilled in the art should know that both the phase change material in this embodiment and the metasurface material can be used as the modulated pixel unit. Therefore, the phase change material unit in this embodiment can also be replaced by a pixel unit made of a metasurface material, etc.

Claims

1. A lightwave complex amplitude modulation device, characterized in that: At least includes a first modulation layer, a second modulation layer and a heat-insulating layer located therebetween; the first modulation layer includes one or more first modulation pixel units, the second modulation layer includes one or more second modulation pixel units; the heat-insulating layer includes one or more heat-insulating pixel units, the light beam modulated by the first modulation pixel unit is projected through a unique heat-insulating pixel unit and only projected to the unique second modulation pixel unit; the first modulation pixel unit and the second modulation pixel unit change their optical properties through signal excitation to achieve modulation of the light beam; The heat-insulating pixel unit is a micrometer-scale optical fiber structure, configured to guide the light beam modulated by the first modulation pixel unit to the second modulation pixel unit for modulation; The number of the heat-insulating pixel units is two or more, and the optical paths of the heat-insulating pixel units are the same.

2. The lightwave complex amplitude modulation device according to claim 1, characterized in that: The first modulation pixel unit is an amplitude modulation unit, and the second modulation unit is a phase modulation unit; or the first modulation pixel unit is a phase modulation unit, and the second modulation unit is an amplitude modulation unit.

3. The lightwave complex amplitude modulation device according to claim 1, characterized in that: The first modulation pixel unit and the second modulation pixel unit are phase change materials, liquid crystal materials or other materials capable of adjusting optical properties.

4. The lightwave complex amplitude modulation device according to claim 3, characterized in that: The phase change material is selected from: GeSbTe, GeSeSbTe, VO2.

5. The lightwave complex amplitude modulation device according to claim 3, characterized in that: The liquid crystal material is selected from: biphenyl liquid crystal, phenylcyclohexane liquid crystal, and ester liquid crystal.

6. The lightwave complex amplitude modulation device according to claim 1, characterized in that: The first modulation pixel unit, the second modulation pixel unit and the heat insulation pixel unit respectively form an array.

7. The lightwave complex amplitude modulation device according to claim 1, characterized in that: The excitation signals of the first modulated pixel unit and the second modulated pixel unit are also modulated by the following method: according to the complex amplitude information A^n(t,λ) and P^n(t,λ) of the target light wave at the nth pixel unit, and the initial complex amplitude information A_0^n(t,λ) and P_0^n(t,λ) of the input light wave at the nth pixel unit, the phase modulation change amount and the amplitude modulation change amount of the nth pixel unit are obtained, and the amplitude attenuation ratio and the phase offset of each of the nth first modulated pixel unit and the nth second modulated pixel unit are obtained by decoupling, and finally the excitation signals applied to the nth first modulated pixel unit and the nth second modulated pixel unit can be obtained.

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