KR102665047B1 - Reflection-type complex-spatial light modulators - Google Patents

Abstract

The present invention relates to a reflective complex spatial light modulator. According to one embodiment, the reflective complex spatial light modulator includes a reflective layer having a plurality of lower electrodes, a birefringent material formed on the reflective layer and having a plurality of birefringent layers, and a birefringent material. A polarization selection element formed on a material, wherein the birefringent material has a common electrode formed on an adjacent surface of the polarization selection element, and a plurality of electrodes that change in response to electrical signals applied to each of the common electrode and the plurality of lower electrodes. The complex amplitude of light incident through the polarization selection element can be adjusted based on the distribution of the birefringent layer.

Description

REFLECTION-TYPE COMPLEX-SPATIAL LIGHT MODULATORS}

The present invention relates to a reflective complex spatial light modulator, and more specifically, to the technical idea of controlling the complex amplitude of the entire complex space with a single pixel.

With advanced social development, various information processing such as phase and amplitude is required in various areas such as light and signal.

In particular, digital holograms and light-based quantum information processing technologies require free control of the phase and amplitude of light. For example, when there is quantum entanglement in a polarized state of light, the polarization of light is required to control gating in the entanglement state. Regardless, there is a need to independently adjust phase and amplitude.

In the field of optical engineering, a device that spatially adjusts the characteristics of light such as amplitude, phase, and polarization of light is called a spatial light modulator.

A typical spatial light modulator (SLM) adjusts only the amplitude or phase, or the amplitude and phase are combined.

Therefore, in order to adjust the complex amplitude of the entire complex space (0pi to 2pi phase * 0 to maximum transmittance or reflectance), it is necessary to combine multiple spatial light modulators or combine multiple pixels into one super-pixel. Use methods, etc.

In other words, a typical, popular spatial light modulator adjusts only either the amplitude or phase information of light, and a typical display device couples the amplitude and phase to each other.

Complex amplitude refers to the phase and amplitude information of light, and complex space or complex plane means that when the electric or magnetic field of light is expressed in phasor form, the x-axis is the Re component of the electric field or magnetic field, and the y-axis is the Im component. It is a space expressed as , where the size of the vector refers to the amplitude and the angle refers to the phase.

In addition, the entire complex space means 0 (i.e. black) to the relatively maximum value (transmittance or reflectivity) for the phase from 0pi to 2pi, and the complex amplitude can be adjusted in the entire complex space, This may mean that all complex amplitude values within a certain radius from the origin can be implemented in complex space.

In general, complex amplitude adjustment can be implemented by combining several pixels of one spatial light modulator or combining several spatial light modulators.

When combining multiple pixels of a single spatial light modulator, there are several methods, but the thin film-type structure allows two to four adjacent pixels to pass through multiple pixels by precisely arranging precisely patterned optical elements. It is a structure that combines one light into one, and in the case of a non-thin film structure, it passes light several times using a PBS (Polarizing Beam Splitter), lens, mirror, etc.

Resolution loss is inevitable for both thin film and non-thin film structures, and thin film structures have the disadvantage of requiring precise optical element technology and arrangement technology, while non-thin film structures have the disadvantage of requiring space for light to move, additional optical elements, and precise arrangement.

A spatial light modulator that adjusts only amplitude is referred to as A-SLM (amplitude only-SLM), and a spatial light modulator that adjusts only phase is referred to as P-SLM (Phase only-SLM).

As previously explained, the method of connecting multiple spatial light modulators is generally a combination of a spatial light modulator that combines amplitude and phase and a P-SLM for compensation and additional phase adjustment, or a combination of A-SLM and P-SLM. It can be seen that it is happening.

Additionally, the most commonly used A-SLM method is the DMD (Digital Micromirror Device) method, which turns incident light on or off by adjusting the angle of a very small mirror.

The light quantity is time-divided, and the average light quantity is adjusted to the average brightness per unit time by controlling the number of on and off cycles.

The DMD method has the advantage of being able to operate at a very high frame rate, but its reflective structure requires physical space for light to enter and reflect, and the structure for use is limited.

In addition, it may be okay for display purposes, but since the amplitude is adjusted in the form of on and off, if you examine the amplitude of the light according to the direction of light and time, you can observe discontinuous light waves, and the presence of light can be observed. Since the amplitude of light is not controlled in the area, there is a problem that it cannot be used in devices where the instantaneous light amount is more important than the average light amount.

The second most frequently used structure of A-SLM is the liquid crystal structure, which is available in both reflective and transmissive structures.

Unlike DMD, the liquid crystal structure allows continuous adjustment in space and time, and continuous amplitude adjustment up to maximum brightness, but the frame rate is much lower than that of DMD.

In the case of most existing A-SLMs, it is theoretically impossible to drive with perfect amplitude, and a certain amount of phase modulation exists. To solve this problem, most existing A-SLMs use additional compensation films or require additional structures.

In other words, it is difficult to identify a spatial light modulator capable of controlling complex amplitude in the entire complex space with a single structure.

Korean Patent No. 10-1505927, “Optical amplitude and phase modulation device” Korean Patent Publication No. 10-2020-0101044, “Multiple image display device providing holographic images” Korean Patent Publication No. 10-2017-0009255, “Spatial light modulator and digital holography using the same” Korean Patent No. 10-1993566, “Phase modulator that modulates light that interacts with a phase modulator”

The present invention is a reflective complex spatial light modulator that uses asymmetrically distributed birefringent layers and a polarization selection element to control the complex amplitude of the entire complex space with a single pixel while maintaining the existing resolution without additional optical elements and a spatial light modulator. We would like to provide.

In addition, the present invention seeks to provide a reflective complex spatial light modulator that can simultaneously adjust the amplitude and phase of light in various optical and quantum optical experiments and applications such as holograms, optical tweezers, optical communication, and quantum communication.

In addition, the present invention arranges a reflective layer below a birefringent material having asymmetrically distributed birefringent layers, so that it has substantially the same function as when the birefringent layers are symmetrically distributed, allowing the complex amplitude of the entire complex space to be adjusted with a single pixel. The object is to provide a reflective complex spatial light modulator that can

In addition, the present invention seeks to provide a reflective complex spatial light modulator that can process the amount of information that is doubled by adjusting the amplitude in at least two phase spaces.

In addition, the present invention seeks to provide a reflective complex spatial light modulator that can continuously adjust from negative amplitude to positive amplitude in phase space based on the relative phase difference in phase space.

A reflective complex spatial light modulator according to an embodiment of the present invention includes a reflective layer having a plurality of lower electrodes, a birefringent material formed on the reflective layer and having a plurality of birefringent layers, and a polarization selection element formed on the birefringent material. Here, the birefringent material has a common electrode formed on an adjacent surface of the polarization selection element and is used as a polarization selection element based on the distribution of a plurality of birefringence layers that change in response to an electrical signal applied to each of the common electrode and the plurality of lower electrodes. The complex amplitude of incident light can be adjusted through .

According to one side, when the first light corresponding to the preset first polarization is incident on the polarization selection element, the first light is incident on the birefringent material, and when the second light corresponding to the second polarization is incident, the second light is transmitted. You can.

According to one side, the first light incident on the birefringent material is reflected through the reflective layer, and the third and fourth lights corresponding to the reflected first light may be incident on the birefringent material.

According to one side, the polarization selection element may cause the third light corresponding to the first polarization among the incident third and fourth lights to be emitted in the incident direction of the first light, and the fourth light may be transmitted.

According to one side, the birefringent material may be arranged so that the polar angle distribution and azimuth distribution of the plurality of birefringent layers are asymmetrically distributed.

According to one side, the plurality of birefringent layers are asymmetrically distributed within the birefringent material, but as the first light passes through the birefringent material twice due to the reflection layer, the complex amplitude can be adjusted to be the same as when distributed symmetrically. .

According to one side, the polarization selection element may be a polarizing beam spiller (PBS).

According to one side, the plurality of birefringent layers may be uniaxial birefringent layers.

According to one side, the plurality of birefringent layers may include a liquid crystal (LC) material.

According to one side, the reflective layer may include at least one of a mirror and a substrate having a reflective surface.

According to one embodiment, the present invention uses asymmetrically distributed birefringent layers and a polarization selection element to control the complex amplitude of the entire complex space with a single pixel while maintaining the existing resolution without additional optical elements and spatial light modulators. there is.

According to one embodiment, the present invention can simultaneously control the amplitude and phase of light in various optical and quantum optics experiments and applications such as holograms, optical tweezers, optical communication, and quantum communication.

According to one embodiment, the present invention arranges a reflective layer below a birefringent material having asymmetrically distributed birefringent layers, so that it performs substantially the same function as when the birefringent layers are symmetrically distributed, and displays the entire area of complex space with a single pixel. The complex amplitude can be adjusted.

According to one embodiment, the present invention is a reflective complex spatial light modulator that processes the amount of information that is doubled by adjusting the amplitude in at least two phase spaces, and generates negative signals in the phase space based on the relative phase difference in the phase space. It can be continuously adjusted from amplitude to positive amplitude.

1A to 1B are diagrams illustrating the operating concept of a reflective complex spatial light modulator according to an embodiment of the present invention.
2A to 2C are diagrams illustrating a reflective complex spatial light modulator according to an embodiment of the present invention.
3A to 3E are diagrams illustrating the director direction of a plurality of birefringent layers constituting a reflective complex spatial light modulator according to an embodiment of the present invention.
4 to 8 are diagrams illustrating a simulation using a reflective complex spatial light modulator according to an embodiment of the present invention.

Specific structural or functional descriptions of the embodiments according to the concept of the present invention disclosed in this specification are merely illustrative for the purpose of explaining the embodiments according to the concept of the present invention. They may be implemented in various forms and are not limited to the embodiments described herein.

Since the embodiments according to the concept of the present invention can make various changes and have various forms, the embodiments will be illustrated in the drawings and described in detail in this specification. However, this is not intended to limit the embodiments according to the concept of the present invention to specific disclosed forms, and includes changes, equivalents, or substitutes included in the spirit and technical scope of the present invention.

Terms such as first or second may be used to describe various components, but the components should not be limited by the terms. The terms are used solely for the purpose of distinguishing one component from another, for example, a first component may be named a second component, and similar Thus, the second component may also be referred to as the first component.

When a component is said to be "connected" or "connected" to another component, it is understood that it may be directly connected to or connected to the other component, but that other components may exist in between. It should be. On the other hand, when it is mentioned that a component is “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between. Expressions that describe the relationship between components, such as “between”, “immediately between” or “directly adjacent to”, should be interpreted similarly.

The terminology used herein is only used to describe specific embodiments and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "include" or "have" are intended to designate the presence of a described feature, number, step, operation, component, part, or combination thereof, and one or more other features or numbers, It should be understood that this does not exclude in advance the possibility of the presence or addition of steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having meanings consistent with the meanings they have in the context of the related technology, and unless clearly defined in this specification, should not be interpreted in an idealized or overly formal sense. No.

Hereinafter, embodiments will be described in detail with reference to the attached drawings. However, the scope of the patent application is not limited or limited by these examples. The same reference numerals in each drawing indicate the same members.

1A to 1B are diagrams illustrating the operating concept of a reflective complex spatial light modulator according to an embodiment of the present invention.

Specifically, FIG. 1A illustrates a conceptual diagram of the operation of a reflective complex spatial light modulator according to an embodiment of the present invention, and FIG. 1B illustrates the complex amplitude (amplitude + A timing diagram to explain the characteristics of controlling phase is illustrated.

Referring to FIG. 1A, the reflective complex spatial light modulator 104 according to an embodiment of the present invention includes an A-SLM 101, which is a spatial light modulator that adjusts only the amplitude, and a spatial light whose phase can be adjusted in binary. The BP-SLM 102, which is a modulator, can play the same role as the simple combined spatial light modulator 103.

Additionally, the reflective complex spatial light modulator 104 can play the same role as the combination of the P-SLM and A-SLM 101, which can be adjusted from 0 to 2pi.

Additionally, the reflective complex spatial light modulator 104 can play the same role as the combined spatial light modulator 103 when only horizontal electric field signals are used.

In the combined spatial light modulator 103, which corresponds to a general complex amplitude control technology, complex amplitude control can be implemented by combining several pixels of one spatial light modulator or combining several spatial light modulators.

When combining multiple pixels of a single spatial light modulator, there are several methods, but the thin film-type structure allows two to four adjacent pixels to pass through multiple pixels by precisely arranging precisely patterned optical elements. It can have a structure that combines one light into one.

The method of connecting multiple spatial light modulators is generally a combination of SLM for coupling amplitude and phase and P-SLM for compensation and additional phase adjustment, or A-SLM and P-SLM.

The reflective complex spatial light modulator 104 according to an embodiment of the present invention is capable of controlling complex amplitude with only a single pixel without additional optical elements, and involves a combination of a reflective layer, asymmetric distribution of a birefringent layer, and a polarization selection element. Includes all structures that

Referring to the timing diagram 110 of FIG. 1B, it can be divided into a first time section 111, a second time section 112, a third time section 113, and a fourth time section 114.

As an example, the timing diagram 110 illustrates the result of adjusting the complex amplitude when the amplitude and phase change in the second to fourth time sections 112 to 114.

The reflective complex spatial light modulator according to an embodiment of the present invention may be a complex amplitude-SLM (C-SLM) that adjusts complex amplitude including amplitude and phase (i.e., amplitude + phase).

In addition, the reflective complex spatial light modulator according to an embodiment of the present invention can adjust phase information while adjusting the vertical electric field to a specific horizontal electric field in order to solve the problem of the prior art that the phase is binary. By adjusting the vertical electric field and the horizontal electric field, the amplitude can be tuned in binary phase space.

The timing diagram 110 is an embodiment of the present invention, and the configuration for adjusting the complex amplitude including the amplitude and phase of the reflective complex spatial light modulator according to an embodiment of the present invention is limited to the timing diagram 110. It doesn't work.

2A to 2C are diagrams illustrating a reflective complex spatial light modulator according to an embodiment of the present invention.

Specifically, FIG. 2A illustrates the structure of a reflective complex spatial light modulator according to an embodiment, and FIGS. 2B to 2C illustrate a process of modulating light in the reflective complex spatial light modulator according to an embodiment.

Referring to FIGS. 2A to 2C, the reflective complex spatial light modulator according to one embodiment uses asymmetrically distributed birefringent layers and a polarization selection element, maintaining the existing resolution without additional optical elements and spatial light modulator and producing a single The complex amplitude of the entire complex space can be adjusted with pixels.

In addition, the reflective complex spatial light modulator can simultaneously control the amplitude and phase of light in various optical and quantum optics experiments and applications such as holograms, optical tweezers, optical communication, and quantum communication.

In addition, the reflective complex spatial light modulator arranges a reflective layer under a birefringent material having asymmetrically distributed birefringent layers, and performs substantially the same function as when the birefringent layers are symmetrically distributed, allowing a single pixel to display the entire complex space. The complex amplitude can be adjusted.

In addition, the reflective complex spatial light modulator processes the amount of information that is doubled by adjusting the amplitude in at least two phase spaces, and continuously moves from negative to positive amplitude in the phase space based on the relative phase difference in the phase space. It can be adjusted.

For this purpose, the reflective complex spatial light modulator, as shown in reference numeral 200, includes a reflective layer 201, a birefringent material 202 formed on the reflective layer 201, and a polarization selection element formed on the birefringent material 202. It may include (204).

For example, the reflective layer 201 may include at least one of a mirror having a reflective surface and a substrate, and the substrate may be a silicon substrate, but is not limited thereto.

Through this, the reflective layer 201 can reflect the light that has transmitted through the birefringent material 202 and provide the reflected light back to the birefringent material 202.

The reflective layer 201 may include a plurality of lower electrodes 201-1, and the birefringent material 202 may include a plurality of birefringent layers 202-1.

Here, the birefringent material 202 has a common electrode (i.e., upper electrode) 203 formed on an adjacent surface of the polarization selection element 204, and each of the common electrode 203 and the plurality of lower electrodes 201-1 The complex amplitude of light incident through the polarization selection element 204 may be adjusted based on the distribution of the plurality of birefringent layers 202-1 that change in response to the electrical signal applied to the light.

According to one side, the reflective complex spatial light modulator does not necessarily adjust multiple amplitudes based on electrical signals, but satisfies the arrangement conditions of the plurality of birefringent layers 202-1 and the polarization conditions of the polarization selection element 204. In this case, the complex amplitude can be adjusted, and this characteristic can be applied to optical SLM.

Hereinafter, unless otherwise specified, it can be assumed that the light incident on the birefringent material 202 is incident parallel to the z-axis plane, and the angle from the z-axis of the incident light is defined as the polar angle from the x-axis to the y-axis. An angle is defined as an azimuth.

According to one side, when the first light corresponding to the preset first polarization is incident, the polarization selection element 204 causes the first light to enter the birefringent material, and when the second light corresponding to the second polarization is incident, the second light is incident. can be transmitted.

For example, the first polarization may be one of x polarization and y polarization, and the second polarization may be a polarization other than one of x polarization and y polarization, but is not limited thereto. no.

In other words, the first polarization may be x-polarization and the second polarization may be y-polarization. Additionally, the first polarization may be y-polarization, and the second polarization may be x-polarization.

The birefringent material 202 may be arranged so that the polar angle distribution and azimuth distribution of the plurality of birefringent layers 202-1 are asymmetrically distributed.

According to one side, the plurality of birefringent layers 202-1 are asymmetrically distributed within the birefringent material 202, but are symmetrical as the first light passes through the birefringent material 202 twice due to the reflection layer 201. It performs the same function as when distributed, and the complex amplitude can be adjusted.

Specifically, in the plurality of birefringent layers 202-1, the phase difference term and the azimuthal direction of the slow axis are substantially symmetrically distributed with respect to the reflection layer 201, so that the entire common phase term determined by the polar angle distribution is formed. The phase can be adjusted based on the sum.

In addition, the plurality of birefringent layers 202-1 are based on a symmetrical distribution of the azimuthal direction of the phase difference term and the slow axis with respect to the reflection layer 201. The amplitude can be adjusted by changing the distribution.

For example, the plurality of asymmetrically distributed birefringent layers 202-1 have a polar angle, which is an angle from the z-axis with respect to the incident first light, and an angle in the x-axis and y-axis directions due to the reflection layer 201. The azimuth angle may be implemented in a substantially symmetrical structure.

For example, for a specific azimuth a, a+-180 degrees play the same role, and for a specific azimuth a and polar angle b, a and -b can also play the same role.

More specifically, the reflective complex spatial light modulator generates a horizontal electric field or a vertical electric field within the birefringent material 202 according to the electrical signal applied through each of the common electrode 203 and the plurality of lower electrodes 201-1. The azimuth angle distribution and polar angle distribution of the plurality of birefringent layers 202-1 are changed according to the formed electric field, and as a result, the complex amplitude of light incident on the birefringent material 202 can be adjusted.

For example, the plurality of birefringent layers 202-1 applies a preset first level voltage to the first lower electrode among the plurality of lower electrodes 201-1, and applies a preset second level voltage to the second lower electrode. When a voltage of is applied, the azimuth distribution may be changed.

In addition, the polar angle distribution of the plurality of birefringent layers 202-1 changes when a preset third level voltage is applied to the common electrode and a preset fourth level voltage is applied to the first lower electrode and the second lower electrode. It can be.

According to one side, the polarization selection element 204 may be a polarizing beam spiltter (PBS), and the plurality of birefringent layers 202-1 may be a homogeneous material that optically exhibits uniaxial birefringence characteristics, which is a type of wavelength. It may correspond to a plate.

For example, the plurality of birefringent layers 202-1 may include a liquid crystal (LC) material, but is not limited thereto.

Here, a uniaxial birefringent layer showing uniaxial birefringence characteristics refers to a material that has the same refractive index ( _no , ordinary refractive index) in two directions and a different refractive index (ne _e , extraordinary refractive index) in one direction, and the director represents _ne . .

Meanwhile, the reflection-type complex spatial light modulator according to an embodiment may be implemented as a transmission-type complex spatial light modulator by replacing the polarization selection element 204 according to an embodiment with a plurality of polarizers and eliminating the reflection layer 201. .

Specifically, the transmission-type complex spatial light modulator arranges a first polarizer below the birefringent material 202, and disposes a second polarizer on top of the birefringent material 202 that is rotated 90 degrees to -90 degrees with respect to the first polarizer to face the other. It can be.

However, in order for the above-described transmission-type complex spatial light modulator to perform the same role as the reflection-type complex spatial light modulator according to one embodiment, a plurality of birefringent layers 202-1 must exist from z = 0 to z = d. (Reflective complex spatial light modulator exists only at z=0~d/2 or z=d/2~d). In the case of a distribution of multiple birefringent layers where it is difficult to satisfy the symmetry condition with a single distribution, an intermediate layer is inserted to create two layers. A method of making it symmetrical must be applied.

On the other hand, the reflection-type complex spatial light modulator according to one embodiment has a simple configuration of a reflection layer 201, a birefringent material 202, and a polarization selection element 204 to produce transmission-type complex space light in a smaller size without considering symmetry conditions. An optical modulator having substantially the same performance as the modulator can be implemented.

Hereinafter, the similarity between the reflective complex spatial light modulator and the transmissive complex spatial light modulator according to an embodiment will be described using Equations 1 to 7.

The optical modulator can be designed based on regular reflection, and can also be implemented with an oblique incidence structure if some error or correction optical components are used.

Specifically, the light modulator can be designed so that light, based on the laboratory coordinate system based on regular reflection, travels in the ±z direction, that is, the direction of incident light and reflected light in the birefringent material travels, and the polarization plane is set to the x, y plane. .

In addition, in the optical modulator, when the incident light on the birefringent material is reflected by the reflection layer, that is, when the reflected light is output, the traveling direction of the light and the axis directions of the optical coordinate system change, so the components constituting the incident light and the reflected light are expressed in Equation 1 below can be defined together.

[Formula 1]

Here, J refers to polarization, M _i refers to the birefringent layer, M _m refers to the birefringent material, and P refers to the polarizer.

The direction of light can be set to the z-axis for both incident and reflection based on the optical coordinate system. When incident is based on the coordinate system, it can be set to the z-axis direction, and when reflected, it can be set to the -z-axis direction. The y-axis coordinate can be set to the same direction in both coordinate systems. can be set.

In addition, the x, y, and z axes directions are set based on the right-handed coordinate system, so the axes directions of the two coordinate systems are the same when incident, but the x, z axes directions of the laboratory and light coordinate systems may be opposite to each other when reflected.

Since the polarization plane is defined as the x and y plane, the subsequent polarization directions of the polarization and birefringent layer, birefringent material, and polarization selection element can be y-axis symmetrical.

As described above, assuming that the homogeneous birefringent layer is M _i , the birefringent material (M _m ) composed of arbitrary M _i can be defined as shown in Equation 2 below.

[Formula 2]

At this time, the transmissive complex spatial light modulator according to one embodiment can be defined as Equation 3 below.

[Formula 3]

Here, J _in is the polarization at incident, J _out is the polarization at exit, P _in is the polarizer at incident, P _out is the polarizer at exit, and M _m,ro is a birefringent material composed of the same birefringent layers as M _m but arranged in reverse order. means, and M _m,ro can be defined as Equation 4 below.

[Formula 4]

If P _øin and P _øout are polarizers rotated ±90 degrees from each other, it is the same as a transmissive complex spatial light modulator, and although it is slightly different, it can operate as an approximate complex spatial light modulator.

Polarization at the midpoint of a plurality of birefringent materials can be defined as Equation 5 below.

[Formula 5]

As described above, at the time of reflection, the directions of the polarized light and the birefringent material act as if they are on the y-axis, and can pass through the birefringent material passed at the time of incidence in the reverse order. This can be expressed as Equation 6 below, Equation 6 Y means a y-axis symmetric matrix.

[Formula 6]

Polarization from reflection to final emission can be defined as Equation 7 below.

[Formula 7]

In other words, the final polarization of the reflective structure is the same as the result of the transmissive structure symmetrical along the Y axis, and except that it is symmetrical along the Y axis, the amplitude and phase are the same as those of the transmissive structure.

During reflection, the phase may change depending on the reflective material, but since the global phase is added to all polarization independent of polarization, except for special materials, there are two structures (transmissive and reflective) in the phase control range and amplitude control range. There is no difference in type).

However, the polarizer, birefringent material, and reflective layer all exist in the same layer, and assuming a general polarizer, the reflective polarizer is a mirror reflection of the incident polarizer, so it satisfies the condition that P _øin and P _øout are rotated ±90 degrees from each other. It is difficult to do this, and therefore, it is desirable to apply a polarization selection element in the reflective type.

In the above description according to Equations 1 to 7, the polar angle and azimuth angle were explained assuming only a function of the z position and assuming uniform characteristics in the xy plane. However, this was assumed for convenience of explanation, and the direction of the directors on each optical path was explained by assuming uniform characteristics in the xy plane. If the polar angle and azimuth distributions maintain symmetry, they can operate identically.

In other words, even if the complex amplitude of the emitted beams is non-uniform depending on the xy position, each beam can operate as a C-SLM according to the principles described, and in this case, the effective emission amplitude can be determined by the sum of each beam. .

Hereinafter, the reflective complex spatial light modulator according to an embodiment of the present invention will be described in more detail through reference numerals 210 to 220.

According to reference numerals 200 to 220, the polarization selection element 204 provided in the reflective complex spatial light modulator selects a first light corresponding to a preset first polarization as indicated by reference numeral '①' and a second light corresponding to the second polarization. When two lights are incident, the second light can be transmitted as indicated by reference numeral '②', and the first light can be incident on the birefringent layer 202 as indicated by reference numeral '③'.

Next, when the incident first light is reflected by the reflection layer 201, the birefringent layer 202 sends the third and fourth lights corresponding to the first light, as indicated by reference numeral '④', to the polarization selection element 204. ), where the third light may correspond to the first polarization and the fourth light may correspond to the second polarization.

Next, when the third light and the fourth light are incident from the birefringent layer 202, the polarization selection element 204 transmits the fourth light corresponding to the second polarization, as indicated by reference numeral '⑤', and the reference numeral '⑤' As shown in ⑥', the third light corresponding to the first polarized light can be emitted in the incident direction of the first light.

That is, the reflective complex spatial light modulator according to an embodiment of the present invention uses the plurality of birefringent materials 202-1 provided in the birefringent layer 202 in the light modulation process of reference numerals '①' to '⑥'. The complex amplitude of light can be adjusted according to changes in distribution.

Specifically, linearly polarized light in a specific direction of the birefringent layer 202 is in the form of a phasor. It can be expressed as follows, the amplitude can be expressed as E ₀ , the phase can be expressed as the angle of E, which is a complex value, and the complex amplitude can be expressed as amplitude and phase.

wavelength The light travels in the z-axis direction and can pass through the polarization selection element 204 located in the xy plane.

The director n of the birefringent layer 202 represents the direction of n _e (extraordinary refractive index), which may be the same as the slow axis direction.

The director n is only a function of z, It is expressed as, is the polar angle, can represent the azimuth angle.

The refractive indices of the birefringent layer 202 are respectively and and where It can be assumed that

Since the birefringent layer 202 is placed on the xy plane and is uniform in the direction of that plane, an effective refractive index can be defined, and the director about It can be expressed as

Here, the effective refractive index can be defined for convenience of calculation in the in-plane direction (perpendicular to the direction perpendicular to the plane) because the electric field generally exists perpendicular to the direction of light travel.

refractive index is the only polar angle is a function of , and in a uniaxial birefringent system, It may be the same as

In general, the Jones matrix of the birefringent layer 202 in the laboratory coordinate system is It is expressed as , and d is the thickness. In the principal coordinate system, the birefringent layer 202 is It is expressed as , and their relational expression may be the same as Equation 8.

[Formula 8]

In Equation 8, M represents the Jones matrix, W may represent the birefringent layer in the principal coordinate system, and R may represent the rotation matrix. means the wave number in vacuum.

Phase difference term ( ) and common phase term ( ) is as follows: , It can be expressed as

As the name suggests, the birefringent layer 202 is an optically anisotropic material, so its refractive index varies depending on the polarization direction of light.

When light travels along the z-axis, polarization in the azimuth direction passes relatively slowly (n _e > n _o ), and polarization in the +90 and -90 degree directions in the azimuth direction can be seen to pass relatively quickly.

That is, polarization in the azimuthal direction may be polarization in the slow axis direction of the birefringent material.

When passing through the birefringent material 202, the average of the phase lags of the two polarized lights is the common phase, and the difference is the phase difference term. Here, the two polarizations may be azimuth direction polarization and azimuth direction polarization of 90 degrees or -90 degrees.

When the common phase term is 0, the off-diagonal component of Equation 8 can represent a pure imaginary value excluding the amplitude. Amplitude and phase are phase difference terms ( ) and azimuth ( ) can be expressed as a function.

When the birefringent material 202 is composed of a plurality of birefringent layers 202-1 as shown in FIGS. 2A to 2C, the slow axis distribution can be changed while maintaining symmetry.

That is, in relation to Equation 8, when it is composed of a plurality of birefringent layers 202-1, the slow axis distribution can be changed while maintaining symmetry with respect to the reflection layer 201.

Additionally, when the first polarizer uses x and the second polarizer uses y in Equation 8, the off-diagonal component value may appear as a complex amplitude value.

When the common phase term is 0, the complex amplitude is a pure imaginary number, which can be interpreted as a result that the phase value is possible as +-pi/2.

Here, the result that a phase value of +-pi/2 is possible can indicate a structure in which amplitude can be adjusted in two phase spaces.

At this time, if polar angle control is added, a C-SLM structure may be possible.

The reflective complex spatial light modulator according to an embodiment of the present invention has a dual phase when the birefringent material 202 or the polarization selection element 204 (i.e., the first to second polarizers) is rotated while maintaining the polar angle. The amplitude can be adjusted in space.

The case of maintaining the above-described polar angle corresponds to the case of amplitude adjustment in a dual phase space, and in order to adjust the complex amplitude, both the polar angle distribution and the azimuth distribution need to be changed.

Although it is stated in Equation 8 that complex amplitude control is possible with a single birefringent layer, in this case, the complex amplitude control area is limited, energy efficiency is relatively low, and control is difficult.

However, when the birefringent layer is composed of a plurality of layers, as in the reflective complex spatial light modulator according to an embodiment of the present invention, the above-mentioned problems can be solved and the configuration can also be made easier. At this time, the complex amplitude can be adjusted by adjusting the polar angle and azimuth angle distributions, similar to when a plurality of birefringent layers are composed of one birefringent layer.

Specifically, when changing the polar angle, the reflective complex spatial light modulator according to an embodiment of the present invention can change both the common phase term and the phase difference term.

For example, a reflective complex spatial light modulator can use a look-up table, where the phase follows only the polar angle, but the amplitude is a function of the polar angle and azimuth, so the desired phase space is fixed at the polar angle, and the You can use an azimuth amplitude lookup table to find the amplitude.

Meanwhile, the plurality of birefringent layers 202-1 may have polar angle changes under a fixed azimuth.

In practice, in order to form a specific azimuth distribution and a specific polar angle distribution, a voltage application operation for changing the azimuth distribution and a voltage application operation for changing the polar angle distribution may be performed alternately, or a combination of specific voltages may be required.

When adjusting the amplitude in the dual phase space, the sum or integral value of the common phase term of the birefringent material 202 composed of the birefringent layers 202-1 can be kept constant, the azimuth distribution can be changed, and the complex SLM can be operated. To do this, adjust the sum or integral value of the common phase term and change the azimuth distribution.

In addition, in the case of a transmissive type, the birefringent material must be distributed mirror image symmetrically with respect to the center, but the reflective complex spatial light modulator according to an embodiment of the present invention is fundamentally designed to be symmetrical with respect to the reflective layer 201. Therefore, there is no need to satisfy the symmetry requirement in the transmissive type.

3A to 3E are diagrams illustrating the director direction of a plurality of birefringent layers constituting a reflective complex spatial light modulator according to an embodiment of the present invention.

3A to 3E illustrate the director directions of various uniaxial birefringent layers, where the uniaxial birefringent layer refers to a material that has the same refractive index in two directions and a different refractive index in one direction.

A director can indicate the direction of a material with a different refractive index in one direction.

In a transmissive complex spatial light modulator structure, light enters and exits from bottom to top or top to bottom.

Here, the angle from the z-axis defines the polar angle, and the angle from the x-axis to the y-axis direction can be defined as the azimuth.

The graph 300, graph 310, graph 320, graph 330, and graph 340 are examples showing only the liquid crystal portion corresponding to the distribution of the birefringent layer of the birefringent material of the complex spatial light modulator, such as electricity. The signals are used to change the graph 300, graph 310, graph 320, graph 330, and graph 340, through which the reflective complex spatial light modulator can adjust the complex amplitude.

In other words, the graph 300, graph 310, graph 320, graph 330, and graph 340 are the distribution of birefringent layers of birefringent material corresponding to the liquid crystal portion of the reflective complex spatial light modulator of the same embodiment. It indicates that the polar angle distribution and azimuth distribution of each director can be adjusted.

According to one embodiment of the present invention, the reflective complex spatial light modulator can adjust the amplitude in a single phase space by adjusting the azimuth distribution while maintaining the polar angle distribution, and the amplitude and phase by adjusting the polar angle distribution while maintaining the azimuth distribution. can be adjusted.

For example, a reflective complex spatial light modulator can adjust from negative to positive amplitude in a single phase space.

Here, the central reference may correspond to the central portion of the z-axis on the graph 300, graph 310, graph 320, graph 330, and graph 340.

In a reflective complex spatial light modulator, the birefringent layers may have a symmetrical distribution based on the reflective layer, and here, the symmetrical distribution requires both polar angle distribution and azimuth distribution to be symmetrical. However, due to the characteristics of the uniaxial birefringent layer, if the polar angle is a and the azimuth angle is b, the polar angle a and the azimuth b+180 degrees may be the same.

Additionally, if the polar angle is c and the azimuth angle is d, the polar angle c may be equal to 180 degrees minus the polar angle c, and the azimuth angle d may be the same.

Graph 300, graph 310, and graph 320 represent symmetrical azimuth changes, graphs 300 and 330 represent symmetrical polar angle changes, and graph 340 represents both polar angle and azimuth ( It shows a symmetrical change compared to 300).

According to one embodiment of the present invention, the reflective complex spatial light modulator can display the birefringent layer corresponding to a very thin, homogeneous liquid crystal material by polar angle, azimuth, and thickness. Alternatively, the common phase It can be expressed in terms of terms, phase difference terms, and the direction of the slow axis.

In addition, the symmetric distribution requires that the phase difference term and the azimuth direction of the slow axis be symmetrically distributed based on the center, and the total sum of the common phase terms can contribute to controlling the overall phase.

Additionally, the amplitude can be adjusted by changing the distribution of the phase difference term and the azimuthal direction of the slow axis while maintaining symmetry while maintaining the common phase term related to the determination of the polar angle distribution.

4 to 8 are diagrams illustrating a simulation using a reflective complex spatial light modulator according to an embodiment of the present invention.

Figure 4 illustrates simulation results for the case where the thickness change and the polar angle distribution of the alignment layer of the reflective complex spatial light modulator according to an embodiment of the present invention are fixed and the azimuth distribution is changed.

Referring to FIG. 4, graphs 400, 410, and 420 illustrate changes in phase related to transmission amplitude, saturation ratio, and azimuth distribution according to changes in the thickness of the reflective complex spatial light modulator.

Additionally, the simulation results in Figure 4 assume that the modulation characteristics of the structure are a function of the rotation of the liquid crystal (LC) director and the applied in-plane electric field.

When the polar angle distribution is fixed, the phase value is fixed, and when the azimuth distribution is adjusted in this state, the amplitude can be adjusted in the phase value and the phase space obtained by adding 180 degrees to the phase value.

In other words, the polar angle changes the phase, and the azimuth angle changes the amplitude in dual phase space.

In addition, the long direction of the director or liquid crystal tends to be aligned in the direction of the electric field.

Therefore, the electric field exists in the direction within the plane, the azimuth angle changes, and the polar angle may change small as the electric field exists in the direction perpendicular to the plane. Here, small changes in polar angle can be corrected using an electric field perpendicular to the plane.

In the graph 400, the thickness of the reflective complex spatial light modulator is 1224 nm, in the graph 410, the thickness of the reflective complex spatial light modulator is 2232 nm, and in the graph 420, the thickness of the reflective complex spatial light modulator is 4360 nm. You can.

In the graph 400, the indicator line 401 indicates a change in transmission amplitude, the indicator line 402 indicates a change in saturation ratio, and the indicator line 403 indicates a change in phase.

Additionally, in the graph 410, the indicator line 411 indicates a change in transmission amplitude, the indicator line 412 indicates a change in saturation ratio, and the indicator line 413 indicates a change in phase.

Additionally, in the graph 420, the indicator line 421 indicates a change in transmission amplitude, the indicator line 422 indicates a change in saturation ratio, and the indicator line 423 indicates a change in phase.

The results shown in graphs 400 to 420 show that the LC director composed of birefringent layers is aligned parallel to the direction of the entrance polarizer but perpendicular to the outlet polarizer. That is, the entrance polarizer and the outlet polarizer form an angle of 90 degrees in the x-y plane.

Reflective complex spatial light modulators can ensure thickness-independent generally black operation.

Referring to the graphs 400 to 420, as the azimuth angle (δΦ(E _xy )) increases or the applied bias voltage increases, the transmission amplitude of the transmission coefficient increases and reaches a peak, and then the relative phase of the transmission coefficient While this is 0, the transmission amplitude decreases to 0. For example, the amplitude of the total velocity may be referred to as the amplitude of the transmission coefficient.

δΦ(Exy) is the azimuthal change width according to the electric field. The birefringent layer is oriented at the top and bottom of the birefringent layer as the voltage is in the direction of the alignment film, but when an electric field exists, it tries to rotate in the direction of the electric field.

Therefore, the top and bottom exist in the direction of the alignment film, and as they move toward the center, they gradually turn in the direction of the electric field. The degree to which they gradually turn may vary depending on the strength of the electric field (and material properties).

This simulation is a specific example, and although the azimuth distribution may change in other ways (while satisfying the symmetry condition), this simulation assumes that the azimuth difference between one birefringent layer and the next is δΦ(Exy), and no matter how strong the electric field is, Since it tries to be aligned in the direction of the electric field, the azimuth direction of the birefringent layer rotates up to the direction of the electric field.

For example, if the azimuth direction of AL is 0 degrees both up and down, and the electric field direction is 90 degrees, when the electric field is weak, it becomes 0 1 2 3 ---89 90 90 90 89 - 3 2 1 0.

Or, if the electric field is weaker, it can be distributed as 0 0.1 0.2 0.3 --- 8.9 9 8.9 - 0.3 0.2 0.1 0, and if it is very strong, it can be distributed as 0 10 20 30 --- 90 90 90 --- 30 20 10 0. .

Referring to graphs 400 to 420, the transmission amplitude increases as the azimuth increases, but the phase of the transmission coefficient jumps to a constant while the portion of the saturation region increases. This modulation operation can be repeated more times as the thickness increases.

Accordingly, an alternating region of constant phase may exist while the transmission amplitude of the transmission coefficient increases or decreases as the zero or azimuth angle changes or the applied electric field is controlled.

The area between the points where the phase size is 0 is where the transmission coefficient is greater than the transmission coefficient. The area between the points where the amplitude size is 0 as the phase jumps +- pi at the part where the amplitude of the transmission coefficient becomes 0. is maintained at a constant phase.

This indicates that amplitude-only optical modulation can be achieved in the constant phase region.

At the same time, optical modulation with phase difference can be achieved by dynamically controlling the applied in-plane electric field, which indicates that when the dynamic modulation width in azimuth is sufficiently wide, binary phase complex optical modulation over zero of the transmission amplitude can be achieved. .

Referring to graphs 400 to 420, the ratio of the saturation region thickness to the total cell thickness clearly indicates that the saturation region becomes wider as the applied bias voltage increases and that there is no saturation region at low bias voltages. In other words, as the cell thickness increases, the saturation area becomes wider.

Figure 5 illustrates simulation results for a case where the thickness of the reflective complex spatial light modulator and the azimuth of the alignment layer are changed by 45 degrees according to an embodiment of the present invention.

Referring to FIG. 5, graphs 500, 510, and 520 illustrate changes in transmission amplitude, saturation ratio, and phase according to thickness changes of the reflective complex spatial light modulator.

The simulation results in Figure 5 assume that the modulation characteristics of the structure are proportional to the rotation of the LC director and the applied in-plane electric field.

In the graph 500, the thickness of the reflective complex spatial light modulator may be 600 nm, in the graph 510, the thickness of the complex spatial light modulator may be 1680 nm, and in the graph 520, the thickness of the complex spatial light modulator may be 2732 nm.

In the graph 500, the indicator line 501 indicates a change in transmission amplitude, the indicator line 502 indicates a change in saturation ratio, and the indicator line 503 indicates a change in phase.

Additionally, in the graph 510, the indicator line 511 indicates a change in transmission amplitude, the indicator line 512 indicates a change in saturation ratio, and the indicator line 513 indicates a change in phase.

Additionally, in the graph 520, the indicator line 521 indicates a change in transmission amplitude, the indicator line 522 indicates a change in saturation ratio, and the indicator line 523 indicates a change in phase.

Referring to graphs 500 to 520, the configuration of the reflective complex spatial light modulator no longer guarantees generally black operation in the off state, but can obtain a state close to black within 0.5 (degrees/nm). there is.

In particular, graphs 500 and 520 show that a nearly perfect black state can be obtained, and the amplitude of the transmission coefficient is close to 0.

Adjusting the transmission amplitude under the binary phase space of the reflective complex spatial light modulator by controlling the cell thickness as shown in graphs 500 to 520 can be achieved in both structures.

The transmittance of the reflective complex spatial light modulator in graphs 500 to 520 may have a cell configuration that is more advantageous compared to the reflective complex spatial light modulator that provides the results in graphs 400 to 420. It indicates that there is.

It can be seen that the reflective complex spatial light modulator in the graphs 500 to 520 can be applied as a limited complex spatial light modulator or a binary phase complex spatial light modulator, and can double the controllability of optical information. there is.

6A to 6B illustrate assumed conditions for performing simulation using a complex spatial light modulator according to an embodiment of the present invention.

Specifically, the graph 600 in FIG. 6A shows the relationship between the change in the order of the LC layers and the change in the polar angle, and the graph 610 in FIG. 9B shows the relationship between the change in the order of the LC layers and the change in the azimuth angle. represents the relationship. Here, the LC layer refers to the birefringent material described above, and the LC layer may be formed of multiple layers of birefringent layers making up the birefringent material.

Referring to the graph 600 and graph 610, for simulation, the incident polarizer was set to 0 degrees and the exit polarizer was set to 90 degrees. Assuming an alignment film, before applying voltage, the director direction of all LCs was set to a polar angle of 90 degrees. The azimuth can be set to 0 degrees.

Afterwards, the horizontal electric field acts in the direction of 90 degrees azimuth and 90 degrees polar angle, and the vertical electric field can be set in the direction of 0 degrees azimuth.

In addition, the strengths of the two electric fields vary depending on the individual signal, so the LC director direction changes linearly as shown below, and the polarization of the incident light can be assumed to be 0 degrees.

The simulation calculates a homogeneous and anisotropic multilayer LC layer through the Jones matrix.

The x-axis of the graphs 900 and 910 is the order in which multiple LC layers are stacked, and can be interpreted as the z-axis height.

Since the complex spatial light modulator according to an embodiment of the present invention has alignment films on the top and bottom planes, the top and bottom portions of the polar angle and azimuth angle are fixed at 90 degrees and 0 degrees, respectively.

In the reflective complex spatial light modulator according to an embodiment of the present invention, the direction of the director changes linearly toward the center due to a vertical electric field and/or a horizontal electric field, and since it cannot rotate beyond the direction of the electric field, It can be saturated in the horizontal electric field direction.

For example, the actual liquid crystal or birefringent layer does not change linearly as in the simulation, but can be approximated linearly, and if the symmetry conditions and polarizer arrangements of the present invention are satisfied, any change (linear change or distribution in the simulation) Likewise), the principles and structure of the present invention can be applied.

Polar angle and azimuth change according to z-axis change , It can be defined as: However, since the birefringent layer does not change continuously and is calculated as a finite multi-layer homogeneous birefringent layer, the effective polar angle and azimuth angle change according to the z-axis change, and discontinuous sections may exist in the simulation.

For example, each birefringent layer is 3 nm, In this case, the azimuth value of each birefringent layer is 0, 3, 6, ~ 90, 90, 90, ~, 6, 3, 0, but the azimuth value in 1nm units is 0, 0, 0, 3, 3, 3, It can be equal to ~ 90, 90, 90, ~, 0, 0, 0, 3, 3, 3.

Figures 7 and 8 show simulation results using a reflective complex spatial light modulator according to an embodiment of the present invention, illustrating the resulting values of various polar angle and azimuth angle changes for eight angles by plotting them in complex space.

In other words, the angles shown in the graphs 700 to 707 and the graphs 800 to 807 express the value of the maximum phase difference term for all polar angles and azimuth angle distributions in each graph, and the phase difference term is the effective refractive index. As the product of the difference, wave number, and thickness, the difference in refractive index and wave number are the same for all graphs, so the difference between graphs 700 to 707 and graphs 800 to 807 can be considered thickness. .

Referring to graphs 700 to 707 of FIG. 7, each point is a change value of polar angle and azimuth angle, and the polar angle is , and the azimuth is It is displayed as This shows how rapidly the director distribution changes in the birefringent layer.

Graph 700 illustrates 180 degrees, graph 701 illustrates 360 degrees, graph 702 illustrates 540 degrees, graph 703 illustrates 720 degrees, and graph 704 illustrates 900 degrees. illustrating degrees, graph 705 illustrates 1080 degrees, graph 706 illustrates 1260 degrees, and graph 707 illustrates 1440 degrees.

Each thickness has a maximum phase control range ( ) were used for birefringence and thickness conditions corresponding to 180 to 1440 degrees, respectively. When the thickness was increased by n times, the number of layers was also increased by n times to keep the thickness per LC layer the same.

Points at the same angle mean the same phase value, and the radius means the transmission coefficient or reflection coefficient. same is plotted with the same color, and the same color means the same phase or same phase. shows. That is, the same The result is Even if is different, it exists in the dual phase space.

A radius of 1 means that all incident light is reflected or transmitted, and a small radius means the maximum reflection and transmission coefficients that can be adjusted from 0pi to 2pi, and as the small radius increases, the light efficiency increases. You can.

The above simulation is a structure created by applying a type of IPS (in-plane switching), but light efficiency can be increased if a different structure or thickness is used.

It can also be seen that the result values are more spread out in a specific phase space, which can be applied even when that characteristic is preferred or when there is no significant difference in the result values implemented by a general spatial light modulator.

Accordingly, the present invention can process the amount of information doubling by adjusting the amplitude in at least two phase spaces.

Additionally, the present invention can continuously adjust from negative amplitude to positive amplitude in phase space based on the relative phase difference in phase space.

Referring to graphs 800 to 807 in FIG. 8, graph 800 illustrates 180 degrees, graph 801 illustrates 360 degrees, graph 802 illustrates 540 degrees, and graph 800 illustrates 180 degrees. Graph 803 illustrates 720 degrees, graph 804 illustrates 900 degrees, graph 805 illustrates 1080 degrees, graph 806 illustrates 1260 degrees, and graph 807 illustrates 1440 degrees. exemplifies.

Graphs 800 to 807 show simulation results using the same simulation method as graphs 700 to 707, but the polar angle and azimuth distribution are different from the simulation method described above.

Specifically, graphs 800 to 807 are more realistic simulations of polar angle and azimuth angle distributions considering the role of molecular motion, have higher energy efficiency, and the present invention describes the principles and conditions. In addition to the two simulations described above, if other polar angle and azimuth distribution conditions are satisfied, the function of C-SLM can be implemented with various efficiencies.

Although the embodiments have been described with limited drawings as described above, various modifications and variations can be made by those skilled in the art from the above description. For example, the described techniques are performed in a different order than the described method, and/or components of the described device, structure, device, circuit, etc. are combined or combined in a different form than the described method, or other components are used. Alternatively, appropriate results may be achieved even if substituted or substituted by an equivalent.

Therefore, other implementations, other embodiments, and equivalents of the claims also fall within the scope of the claims described below.

200: reflective complex spatial light modulator 201: reflective layer
201-1: lower electrode 202: birefringent material
202-1: plurality of birefringent layers 203: common electrode
204: Polarization selection element

Claims (10)

A reflective layer having a plurality of lower electrodes;
A birefringent material formed on the reflective layer and having a plurality of birefringent layers, and
Polarization selection element formed on the birefringent material
Including,
The birefringent material has a common electrode formed on a surface adjacent to the polarization selection element, and the distribution of the plurality of birefringent layers changes in response to electrical signals applied to each of the common electrode and the plurality of lower electrodes. The complex amplitude of light incident through the polarization selection element is adjusted,
When first light corresponding to a preset first polarization is incident on the polarization selection element, the first light is incident on the birefringent material, and when second light corresponding to the second polarization is incident, the second light is transmitted. ,
The birefringent material causes the incident first light to be reflected through the reflective layer, and third and fourth lights corresponding to the reflected first light are incident to the birefringent material,
The birefringent material is arranged so that the polar angle distribution and azimuth distribution of the plurality of birefringent layers are asymmetrically distributed.
Reflective complex spatial light modulator. delete delete According to paragraph 1,
The polarization selection element is characterized in that among the incident third light and fourth light, the third light corresponding to the first polarization is emitted in the incident direction of the first light, and the fourth light is transmitted.
Reflective complex spatial light modulator. delete A reflective layer having a plurality of lower electrodes;
A birefringent material formed on the reflective layer and having a plurality of birefringent layers, and
Polarization selection element formed on the birefringent material
Including,
The birefringent material has a common electrode formed on a surface adjacent to the polarization selection element, and the distribution of the plurality of birefringent layers changes in response to electrical signals applied to each of the common electrode and the plurality of lower electrodes. The complex amplitude of light incident through the polarization selection element is adjusted,
When first light corresponding to a preset first polarization is incident on the polarization selection element, the first light is incident on the birefringent material, and when second light corresponding to the second polarization is incident, the second light is transmitted. ,
The birefringent material causes the incident first light to be reflected through the reflective layer, and third and fourth lights corresponding to the reflected first light are incident to the birefringent material,
The plurality of birefringent layers are asymmetrically distributed within the birefringent material, and the complex amplitude is adjusted in the same way as when the first light is symmetrically distributed as it passes through the birefringent material twice due to the reflective layer. characterized by
Reflective complex spatial light modulator. According to paragraph 1,
The polarization selection element is characterized in that it is a polarizing beam splitter (PBS).
Reflective complex spatial light modulator. According to paragraph 1,
Characterized in that the plurality of birefringent layers are uniaxial birefringent layers.
Reflective complex spatial light modulator. According to paragraph 1,
The plurality of birefringent layers are characterized in that they include a liquid crystal (LC) material.
Reflective complex spatial light modulator. According to paragraph 1,
The reflective layer is characterized in that it includes at least one of a mirror and a substrate having a reflective surface.
Reflective complex spatial light modulator.