CN110647024B - Method for realizing circuitous phase coding multiplexing based on super-surface array structure - Google Patents
Method for realizing circuitous phase coding multiplexing based on super-surface array structure Download PDFInfo
- Publication number
- CN110647024B CN110647024B CN201911043883.3A CN201911043883A CN110647024B CN 110647024 B CN110647024 B CN 110647024B CN 201911043883 A CN201911043883 A CN 201911043883A CN 110647024 B CN110647024 B CN 110647024B
- Authority
- CN
- China
- Prior art keywords
- nano
- brick
- super
- linearly polarized
- polarized light
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000000034 method Methods 0.000 title claims abstract description 38
- 239000011449 brick Substances 0.000 claims abstract description 123
- 238000005070 sampling Methods 0.000 claims abstract description 67
- 238000002834 transmittance Methods 0.000 claims abstract description 52
- 230000010287 polarization Effects 0.000 claims abstract description 28
- 239000011159 matrix material Substances 0.000 claims abstract description 27
- 238000001093 holography Methods 0.000 claims abstract description 16
- 230000005540 biological transmission Effects 0.000 claims description 25
- 239000000758 substrate Substances 0.000 claims description 21
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 8
- 238000009826 distribution Methods 0.000 claims description 7
- 238000005315 distribution function Methods 0.000 claims description 7
- 229910052709 silver Inorganic materials 0.000 claims description 5
- 239000004332 silver Substances 0.000 claims description 5
- 239000000377 silicon dioxide Substances 0.000 claims description 4
- 235000012239 silicon dioxide Nutrition 0.000 claims description 3
- 230000000737 periodic effect Effects 0.000 claims description 2
- 230000010355 oscillation Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 5
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000013500 data storage Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/26—Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
- G03H1/2645—Multiplexing processes, e.g. aperture, shift, or wavefront multiplexing
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/26—Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
- G03H1/2645—Multiplexing processes, e.g. aperture, shift, or wavefront multiplexing
- G03H2001/2675—Phase code multiplexing, wherein the sub-holograms are multiplexed according to spatial modulation of the reference beam
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Holo Graphy (AREA)
Abstract
The invention discloses a method for realizing circuitous phase coding multiplexing based on a super-surface array structure, which comprises the following steps: step 1, optimally designing a nano brick unit structure which can be equivalent to a micro polarizer; step 2, the transmittance codes corresponding to the nano brick unit structures; step 3, designing a sampling unit to realize complex amplitude modulation; step 4, designing complex amplitude holographic multiplexing; step 5, generating transmittance coding information, and obtaining a direction angle matrix containing four kinds of direction angle information; and 6, arranging the nano brick unit structures at equal intervals to form a super-surface array structure. The roundabout phase encoding multiplexing design method provided by the invention is simple, flexible in design and easy to operate, can realize complex amplitude holography, and can generate two completely different holographic sheets by changing the polarization state of incident linearly polarized light so as to realize complex amplitude holography multiplexing; the super-surface array structure has the advantages of simple structure, small volume, light weight and compact structure, and has great industrialization prospect.
Description
Technical Field
The invention relates to the technical field of micro-nano optics, in particular to a method for realizing circuitous phase coding multiplexing based on a super-surface array structure.
Background
Computer holography has been widely used in the fields of three-dimensional holographic imaging and optical data storage, etc. to record amplitude and phase information of a target object by approximation and digitization, and then reproduce the recorded complex amplitude information and reproduce the wave front. Most current computer-generated holography devices only provide amplitude or phase modulation, however, theoretically, in order to perfectly reproduce the light wave profile, the amplitude and the phase of the light wave need to be modulated at the same time, that is, the complex amplitude of the light wave needs to be modulated.
The super-surface is a plane optical element with a sub-wavelength scale structure, which is designed and manufactured manually, can flexibly and effectively regulate and control a light wave electromagnetic field in the sub-wavelength scale, is widely applied to wavefront engineering, and the holography is promoted to make a great progress under the promotion of super-surface research.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a method for realizing roundabout phase code multiplexing based on a super-surface array structure by combining the super-surface array structure aiming at the defects in the prior art, and the roundabout phase code multiplexing can be realized only by changing the polarization state of incident linearly polarized light.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the invention provides a method for realizing circuitous phase coding multiplexing based on a super-surface array structure, which comprises the following steps:
2, selecting four nano brick unit structures with different direction angles, and changing the corresponding transmittance of the nano brick unit structures by changing the polarization state of incident linear polarized light to form four codes;
step 3, the sampling unit comprises t multiplied by t nano brick unit structures, the number of the nano brick unit structures of the transmission part of the sampling unit is changed to control the transmittance of the sampling unit, namely, the light transmission area of the clear aperture is changed to code the amplitude, and meanwhile, the positions of the center of the clear aperture and the center of the sampling unit are changed to code the phase, so that complex amplitude holography is realized;
Step 5, matrix T1And matrix T2The element positions of (a) are in one-to-one correspondence, and the matrix T is formed1And matrix T2Simultaneously generating transmission rate coding information, and correspondingly obtaining a direction angle matrix only containing information corresponding to four direction angles according to the coding information in the step 2;
and 6, arranging the nano brick unit structures with the consistent size and the direction angles arranged according to the direction angle matrix at equal intervals in the x direction and the y direction to form the super surface array structure.
Further, the dimensional parameters of the nano-brick unit structure in step 1 of the present invention include: the length L, the width W, the height H and the side length C of the unit structure substrate of the nano brick.
Further, the orientation angles Φ of the nano-brick unit structures in step 2 of the present invention are 22.5 °, 67.5 °, 112.5 ° and 157.5 °, and the incident light is linearly polarized light with θ ═ 0 ° and θ ═ 45 °; the transmittances corresponding to the nano-brick unit structures at the four direction angles are respectively 0, 1 and 1, and when the polarization state of incident linearly polarized light is changed, the transmittances corresponding to the nano-brick unit structures are changed to form four codes of 00, 10, 11 and 01.
Further, the complex amplitude distribution function adopted in step 4 of the present invention is:
holographic plate H1The complex amplitude distribution of the (m, n) -th sampling unit in (a) is:
holographic plate H2The complex amplitude distribution of the (m, n) -th sampling unit in (a) is:
wherein A ismn1And Amn2For holographic disk H1And hologram H2Normalized amplitude of (i.e. 0 ≦ A)mn1≤1，0≤Amn2≤1；
And
for holographic disk H1And hologram H2The phase of (c).
Further, in step 6 of the present invention, the super-surface array structure is composed of a substrate and a nano-brick array etched on the substrate, and the nano-brick array is composed of (M × t) × (N × t) nano-brick unit structures.
Furthermore, the substrate material of the invention is silicon dioxide, and the nano brick unit structure material is silver.
Furthermore, the working wavelength in step 1 of the present invention is 633 nm.
Furthermore, when the working wavelength of the invention is 633nm, the length of the nano brick is 160nm, the width of the nano brick is 80nm, the height of the nano brick is 70nm, and the side length of the unit structure substrate is 300 nm.
The invention has the following beneficial effects: the method for realizing roundabout phase encoding multiplexing based on the super-surface array structure can realize complex amplitude holographic multiplexing only by changing the polarization state of incident linearly polarized light, and has the following advantages:
(1) the roundabout phase encoding multiplexing design method provided by the invention is simple, flexible in design and easy to operate, not only can realize complex amplitude holography, but also can generate two completely different holographic sheets by changing the polarization state of incident linearly polarized light so as to realize complex amplitude holography multiplexing;
(2) the super surface material (i.e. super surface array structure) has simple structure, small volume, light weight and compact structure, the related super surface manufacturing process is mature and simple, and can be copied and produced in large scale and at low cost, thereby having great industrialization prospect.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
fig. 1 is a schematic diagram of a direction angle of a nano-brick unit structure in a method for realizing roundabout phase coding multiplexing based on a super-surface array structure according to an embodiment of the present invention;
fig. 2 is a schematic size parameter diagram of a nano-brick unit structure in a method for implementing roundabout phase encoding multiplexing based on a super-surface array structure according to an embodiment of the present invention;
fig. 3 shows reflection and transmission efficiencies of a nano-brick unit structure designed in a method for implementing roundabout phase encoding multiplexing based on a super-surface array structure according to an embodiment of the present invention for linearly polarized light with two orthogonal polarization states vibrating in the major axis direction and the minor axis direction, respectively;
fig. 4 is a table of transmittance coding information corresponding to direction angles Φ of 22.5 °, 67.5 °, 112.5 °, and 157.5 ° when incident light is linearly polarized light with θ being 0 ° and θ being 45 ° in a method for implementing detour phase coding multiplexing based on a super-surface array structure according to an embodiment of the present invention;
FIG. 5 is a schematic diagram illustrating a principle of phase modulation implemented by a holographic sampling unit in a method for implementing roundabout phase encoding multiplexing based on a super-surface array structure according to an embodiment of the present invention;
fig. 6 is a schematic diagram illustrating a principle that a hologram sampling unit implements complex amplitude modulation in a method for implementing detour phase encoding multiplexing based on a super-surface array structure according to an embodiment of the present invention;
fig. 7 is an encoding process of implementing complex amplitude multiplexing by any sampling unit in a hologram in a method for implementing roundabout phase encoding multiplexing based on a super-surface array structure according to an embodiment of the present invention;
fig. 8 is a schematic diagram of a super-surface array structure formed by arranging four kinds of nano-brick unit structures with consistent size and direction angles of 22.5 °, 67.5 °, 112.5 °, and 157.5 ° at equal intervals in x and y directions in a method for realizing bypass phase coding multiplexing based on the super-surface array structure according to an embodiment of the present invention;
wherein, 1-nano brick unit structure and 2-substrate.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The embodiment provides a method for realizing roundabout phase coding multiplexing based on a super-surface array structure, which is characterized in that the transmittance of a sampling unit is controlled by changing the number of nano brick unit structures of a transmission part of the sampling unit, namely, the light transmission area of a clear aperture is changed to code amplitude, and the positions of the center of the clear aperture and the center of the sampling unit are changed to code phase, so that complex amplitude holography is realized. In addition, under the condition that the super-surface array structure is fixed, the complex amplitude distribution function of the holographic plate can be changed by adjusting the polarization state of incident linearly polarized light, so that complex amplitude holographic multiplexing is realized.
The method for realizing circuitous phase coding multiplexing based on the super surface array structure mainly comprises the following steps:
and 2, coding the transmittance corresponding to the nano brick unit structure. Selecting four nano brick unit structures with phi of 22.5 degrees, 67.5 degrees, 112.5 degrees and 157.5 degrees and different direction angles, wherein when incident light is linearly polarized light with theta of 0 degree, the transmittance corresponding to the nano brick unit structures with the four direction angles is 0, 1 and 0 respectively; when the incident light is linearly polarized light with theta being 45 degrees, the transmittances corresponding to the nano-brick unit structures of the four direction angles are respectively 0, 1 and 1, namely when the polarization state of the incident linearly polarized light is changed, the transmittances corresponding to the nano-brick unit structures are also changed, and four codes of 00, 10, 11 and 01 can be formed;
and 3, designing a sampling unit to realize complex amplitude modulation. The sampling unit comprises t multiplied by t nano brick unit structures, the transmittance of the sampling unit is controlled by changing the number of the nano brick unit structures of the transmission part (the transmittance is 1) of the sampling unit, namely, the light transmission area of the clear aperture is changed to code the amplitude, and meanwhile, the positions of the center of the clear aperture and the center of the sampling unit are changed to code the phase, so that complex amplitude holography is realized;
and 4, designing complex amplitude holographic multiplexing. Suppose two holograms H1And H2Respectively contains M × N sampling units, wherein the complex amplitude distribution of the (M, N) th sampling unit is respectively
And
h is to be1And H2Generates two 0-1 transmittance matrixes T of (M x T) × (N x T) elements according to the step 3 coding1And T2；
Step 5, T1And T2The element positions of (A) are in one-to-one correspondence, and T is set1And T2Generating transmission rate coding information by matrix simultaneous, and correspondingly obtaining a direction angle matrix phi only containing four kinds of direction angle information of 22.5 degrees, 67.5 degrees, 112.5 degrees and 157.5 degrees according to the coding information in the step 2;
and 6, arranging the nano brick unit structures with consistent (M x t) x (N x t) sizes and direction angles arranged according to the direction angle matrix phi at equal intervals in the x and y directions to form the super-surface array structure.
The present invention is further described below.
1. The optimized design can be equivalent to a nano brick unit structure of a miniature polarizer.
The following description will be given taking the nano-brick unit structure as a rectangular parallelepiped. The length, width and height of the nano brick unit structure are all sub-wavelength.
As shown in fig. 1, an xoy rectangular coordinate system is established, the long side direction of the nano-brick unit structure 1 represents a long axis, the short side direction represents a short axis, and Φ is an included angle between the long axis and the x axis of the nano-brick unit structure 1, i.e., a direction angle (Φ is 0 ° -180 °) of the nano-brick unit structure 1, as shown in fig. 1.
Due to the difference in the long and short axis dimensions of the nano-tile unit structure 1, the electromagnetic response in both directions will also be different. The dimension parameters of the nano-brick unit structure, including the height H, length L, width W and unit structure base side length C of the nano-brick unit structure 1 (i.e. equivalent to dividing the substrate 2 into a plurality of unit structure bases), are optimized by electromagnetic simulation software, as shown in fig. 2. When linearly polarized light in any polarization state under working wavelength is normally incident to the nano brick unit structure 1, a group of size parameters with the smallest linearly polarized light component transmittance vibrating along the major axis direction of the nano brick unit structure 1 and the largest linearly polarized light component transmittance vibrating along the minor axis direction of the nano brick unit structure 1, namely the optimized size parameters of the nano brick unit structure 1, are obtained.
Because the linearly polarized light in any polarization state can be decomposed into two orthogonally polarized linearly polarized light, when the linearly polarized light in any polarization state is normally incident on the nano-brick unit structure under the working wavelength, the linearly polarized light component with the vibration direction consistent with the long axis direction of the nano-brick unit structure is reflected, and the linearly polarized light component with the vibration direction consistent with the short axis direction of the nano-brick unit structure is directly transmitted. Therefore, the nano brick unit structure after optimized design by electromagnetic simulation software can realize the function of polarization light splitting, and is equivalent to a miniature polarizer.
2. Sampling unit design and complex amplitude modulation principle.
(1) And (4) coding the transmittance.
Because the nano brick unit structure can be used as a miniature polarizer, the following requirements are met:
Iout＝Iinsin2(Φ-θ) (1)
wherein, IinIs the intensity of incident light, IoutAnd theta is the included angle between the vibration direction of the incident linearly polarized light and the x axis (the value range of theta is 0-180 DEG) for the light intensity of transmitted light.
From the formula (1), for a given θ, namely the polarization state of incident linearly polarized light, changing the direction angle Φ of the nano-brick unit structure, the light intensity of the transmitted light changes accordingly. Due to sin2(phi-theta) is a periodic even function, memoryAt two different direction angles phi1And phi2So that the incident light is incident on two beams with different direction angles phi1And phi2When the nano-bricks are arranged on the base plate, the light intensity of the transmitted light is the same. When theta is changed, the two beams are incident at different direction angles phi1And phi2When the nano-bricks are arranged on the surface of the substrate, the transmitted light intensity is different.
In particular, when the direction angles Φ of the nanoblock unit structures are 22.5 °, 67.5 °, 112.5 ° and 157.5 °, as shown in fig. 4, when the incident light is linearly polarized light with θ ═ 0 °, the transmittances corresponding to the nanoblock unit structures of the four direction angles are 0, 1, and 0, respectively; when the incident light is linearly polarized light with theta being 45 degrees, the transmittances corresponding to the nano-brick unit structures of the four direction angles are respectively 0, 1 and 1, namely when the polarization state of the incident linearly polarized light is changed, the transmittances corresponding to the nano-brick unit structures are also changed, and four codes of 00, 10, 11 and 01 can be formed.
(2) Phase modulation in complex amplitude is achieved using the diffraction effect of an irregular grating.
As shown in FIG. 5, when a plane wave perpendicularly irradiates a line grating, assuming that the pitch is constant, the K-th diffraction order is a plane wave, the equiphase plane is a plane perpendicular to the diffraction direction, and the pitch is d, the K-th diffraction angle is smaller by θKThen, as can be seen from the grating equation, at θKThe optical path difference of the adjacent light rays in the direction is as follows:
LK＝d sinθK＝Kλ (2)
if the grid distance at a certain position is increased by delta, the position is along thetaKThe optical path difference of the directionally adjacent light rays becomes:
LK’＝(d+Δ)sinθK(3)
then thetaKThe phase delay introduced at this location by the directionally diffracted light waves is:
the value of the phase delay is related only to the pitch shift amount and the diffraction order, and it can be seen from equation (4) that by changing the grating pitch locally, a desired phase modulation can be obtained in a certain diffraction direction, and the phase is called a winding phase.
(3) Sampling unit design and complex amplitude modulation principle.
The encoding method for converting a complex-valued function into a real-valued non-negative function is to represent one complex-valued function as two real-valued non-negative functions, i.e. to represent the complex amplitude with two real parameters of amplitude and phase, and to encode the amplitude and phase separately, which is called detour phase encoding.
Suppose that the hologram has a total of M × N sampling cells with a sampling interval ofxAndyeach sampling unit contains t × t nano-brick unit structures with uniform size and orientation angles Φ of 22.5 °, 67.5 °, 112.5 ° and 157.5 °, as shown in fig. 6, then:
x＝y＝t*C (5)
the complex amplitude of the light wave recorded by the (m, n) th sampling unit on the hologram is set as follows:
wherein A ismnIs normalized amplitude, i.e. 0 ≦ Amn≤1；
Is the phase.
The number of the nano-brick unit structures of the sampling unit is kept unchanged, the transmittance of the sampling unit is controlled by changing the number of the nano-brick unit structures of the transmission part of the sampling unit, namely, the light transmission area of the clear aperture is changed to code the amplitude, and meanwhile, the positions of the center of the clear aperture and the center of the sampling unit are changed to code the phase, so that the complex amplitude holography is realized.
In fig. 6, the gray area is composed of the nano brick unit structure with the transmittance of 0, and the area is opaque; the white area represents the transmission part of the sampling unit, namely the light transmission caliber, and is composed of a nano brick unit structure with the transmittance of 1. The width of the light-transmitting aperture is WxW is a constant and has a height Lmn yWith normalized amplitude AmnIs in direct proportion. Pmn xThe distance between the center of the clear aperture and the center of the sampling unit is proportional to the phase of the sampling unit. The relationship between aperture parameter and complex amplitude is as follows:
the above coding method adopts width modulation in y direction for recording amplitude information; position modulation is used in the x-direction for recording phase information, both of which record complex amplitude information of the light wave. The hologram produced by the encoding method can reproduce a hologram image recorded by the hologram at a specific diffraction order K along the x direction.
3. The method is based on the principle of complex amplitude holographic multiplexing of a sampling unit and a holographic design method.
(1) The complex amplitude information of the hologram is encoded as a 0-1 transmittance matrix of the sampling cells.
Suppose two holograms H1And H2There are M × N sampling units, the complex amplitude distribution of the (M, N) th sampling unit is respectively
And
h is to be1And H2The complex amplitude information of the hologram is encoded by the equation (7) to generate two 0-1 transmittance matrices T including (M × T) × (N × T) elements according to the sampling unit complex amplitude modulation principle, that is, the amplitude is encoded by changing the light transmission area of the clear aperture, the phase is encoded by changing the positions of the center of the clear aperture and the center of the sampling unit, and the phase is encoded by changing the angles θ between the vibration direction and the x axis to 0 ° and θ to 45 °1And T2，T1And T2The element positions of (a) are in one-to-one correspondence.
(2) The principle of detour phase code multiplexing.
Linear polarized light with an incident angle θ of 0 ° is assumedThen, a hologram H is correspondingly generated1When the 0-1 transmittance matrix of the nano brick unit structure is T1(ii) a When linearly polarized light with an angle theta of 45 DEG is incident, a hologram H is generated correspondingly2When the 0-1 transmittance matrix of the nano brick unit structure is T2。T1And T2As can be seen from fig. 4, the transmittance of the nano-brick unit structure at four direction angles of 22.5 °, 67.5 °, 112.5 ° and 157.5 ° when linearly polarized light with θ of 0 ° and θ of 45 ° is incident is 0, 1, 0 and 0, 1 and 1, respectively, and four codes of 00, 10, 11 and 01 can be formed. Thus can change T1And T2The orientation angle information of the nano-brick unit structures with the consistent size and the orientation angles arranged according to the orientation angle matrix phi is arranged at equal intervals in the x direction and the y direction to form a super-surface array structure (M x t) × (N x t) to generate the orientation angle matrix phi only containing the four orientation angle information of 22.5 degrees, 67.5 degrees, 112.5 degrees and 157.5 degrees.
(3) And designing a complex amplitude type holographic plate based on the super surface array structure.
The complex amplitude type holographic plate based on the super surface array structure is composed of a substrate and a nano brick array on the substrate, wherein the nano brick array is formed by arranging nano brick unit structures with consistent (M x t) x (N x t) sizes and direction angles arranged according to a direction angle matrix phi at equal intervals in the x direction and the y direction, and is shown in figure 8.
When the super-surface array structure is fixed, the polarization state of incident linearly polarized light is adjusted, and the hologram is irradiated by linearly polarized light with θ being 0 ° and θ being 45 °, respectively, the hologram can realize two completely different complex amplitude distribution functions, that is, complex amplitude holographic multiplexing.
The working mode of the complex amplitude type holographic plate is a transmission mode, the substrate material is a silicon dioxide substrate, and the nano brick unit structure material is silver, but not limited thereto.
To sum up, the method for realizing roundabout phase encoding multiplexing based on the super-surface array structure mainly comprises the following steps:
(1) optimizing the size parameter of the nano brick unit structure to be equivalent to a micro polarizer;
(2) the transmittance codes corresponding to the nano brick unit structures;
(3) designing a hologram sampling unit;
(4) and designing a complex amplitude holographic plate based on roundabout phase encoding multiplexing.
The invention will be further explained with reference to the drawings.
In the method for realizing detour phase encoding multiplexing based on the super-surface array structure provided by this embodiment, detour phase encoding multiplexing based on the super-surface array structure is realized for incident linearly polarized light with an included angle θ of 0 ° and an included angle θ of 45 ° between the vibration direction and the x axis, and the function that the hologram can realize two completely different complex amplitude distribution functions when the incident linearly polarized light with θ of 0 ° and the incident linearly polarized light with θ of 45 ° are respectively incident on the hologram, that is, the invention can realize detour phase encoding multiplexing based on the super-surface array structure.
In this embodiment, the nano unit structure is composed of a silica substrate and silver nano bricks etched on the substrate, the design wavelength is selected to be λ 633nm, and for the wavelength, the nano brick unit structure is optimized and simulated by the electromagnetic simulation software CST, so as to obtain the optimized silver nano bricks with the size parameters: the length is 160nm, the width is 80nm, the height is 70nm, and the side length of the unit structure substrate is 300 nm. The reflection and transmission efficiency of the nano-brick unit structure under the structural parameters to linearly polarized light with two orthogonal polarization states vibrating along the major axis and the minor axis directions respectively is shown in figure 3, wherein Rl、TlRespectively representing the reflectance and transmittance, R, of linearly polarized light vibrating in the major axis direction of the nano-brick unit structures、TsRespectively, the reflectance and transmittance of linearly polarized light vibrating in the minor axis direction of the nanoblock unit structure. As can be seen from FIG. 3, R is measured at the wavelength of the incident light between 550nm and 700nmlAnd TsIs relatively high, RsAnd TlThe value of (a) is relatively low. Especially at the working wavelength of 633nmLower, RlAnd TsGreater than 90%, RsAnd TlLess than 10 percent, which shows that the linearly polarized light vibrating along the short axis direction almost completely transmits, but the linearly polarized light vibrating along the long axis direction only transmits a small amount of light, namely the optimized nano-brick unit structure can realize the function of polarization and light splitting and can be equivalent to a micro polarizer.
In this embodiment, when the direction angles Φ of the nano-brick unit structures are 22.5 °, 67.5 °, 112.5 ° and 157.5 °, as shown in fig. 4, when the incident light is linearly polarized light with θ being 0 °, the transmittances corresponding to the nano-brick unit structures at the four direction angles are 0, 1 and 0, respectively; when the incident light is linearly polarized light with theta being 45 degrees, the transmittances corresponding to the nano-brick unit structures of the four direction angles are respectively 0, 1 and 1, namely when the polarization state of the incident linearly polarized light is changed, the transmittances corresponding to the nano-brick unit structures are also changed, and four codes of 00, 10, 11 and 01 can be formed.
The sampling unit comprises t multiplied by t four nano brick unit structures with consistent size and direction angles phi of 22.5 degrees, 67.5 degrees, 112.5 degrees and 157.5 degrees, the number of the nano brick unit structures of the sampling unit is kept unchanged, the transmittance of the sampling unit is controlled by changing the number of the nano brick unit structures of the transmission part of the sampling unit, namely the light transmission area of the clear aperture is changed to code the amplitude, and meanwhile, the positions of the center of the clear aperture and the center of the sampling unit are changed to code the phase, so that complex amplitude holography is realized.
Taking a sampling unit at an arbitrary position of the hologram as an example, assuming that T is 8, incident linearly polarized light is linearly polarized light with θ being 0 ° and θ being 45 °, and the 0-1 transmittance matrix of the corresponding sampling unit is T1And T2As shown in fig. 7. As can be seen from the figure, when the polarization state of incident light is different, the light transmission area of the corresponding clear aperture and the positions of the center of the clear aperture and the center of the sampling unit are different, so the corresponding complex amplitudes are also different. T is1And T2The element positions of (A) are in one-to-one correspondence, and T is set1And T2The transmission rate coding information is generated simultaneously by the matrix, and four values including only 22.5 °, 67.5 °, 112.5 ° and 157.5 ° are obtained by correspondence from the coding information table of fig. 4The direction angle matrix Φ of the seed direction angle information. The other sampling units of the hologram are designed in the same way, and are not described in detail here.
By adjusting the polarization state of incident linearly polarized light, when a designed hologram is irradiated with linearly polarized light having θ of 0 ° and θ of 45 °, the hologram can realize two completely different complex amplitude distribution functions, that is, complex amplitude holographic multiplexing.
The method for realizing circuitous phase coding multiplexing based on the super-surface array structure provided by the embodiment of the invention at least comprises the following technical effects:
(1) the roundabout phase encoding multiplexing design method provided by the invention is simple, flexible in design and easy to operate, not only can realize complex amplitude holography, but also can generate two completely different holographic sheets by changing the polarization state of incident linearly polarized light so as to realize complex amplitude holography multiplexing;
(2) the super surface material (i.e. super surface array structure) has simple structure, small volume, light weight and compact structure, the related super surface manufacturing process is mature and simple, and can be copied and produced in large scale and at low cost, thereby having great industrialization prospect.
It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.
Claims (8)
1. A method for realizing roundabout phase code multiplexing based on a super-surface array structure is characterized by comprising the following steps:
step 1, determining a working wavelength, and optimizing the size parameters of a nano brick unit structure through electromagnetic simulation software, so that when linearly polarized light in any polarization state under the working wavelength is normally incident to the nano brick unit structure, the linearly polarized light component transmittance vibrating along the major axis direction of the nano brick unit structure is minimum, and the linearly polarized light component transmittance vibrating along the minor axis direction of the nano brick unit structure is maximum;
2, selecting four nano brick unit structures with different direction angles, and changing the corresponding transmittance of the nano brick unit structures by changing the polarization state of incident linear polarized light to form four codes;
the method for selecting the direction angle specifically comprises the following steps:
the nano-brick unit structure is used as a miniature polarizer, thus satisfying the following conditions:
Iout＝Iinsin2(Φ-θ)
wherein, IinIs the intensity of incident light, IoutThe intensity of transmitted light is theta, the included angle between the vibration direction of incident linearly polarized light and the x axis is theta, the value range of theta is 0-180 degrees, and the direction angle is phi; for a given theta, namely the polarization state of incident linearly polarized light is determined, the direction angle phi of the unit structure of the nano brick is changed, and then the light intensity of transmitted light is changed; due to sin2(phi-theta) is a periodic even function with two different orientation angles phi1And phi2So that the incident light is incident on two beams with different direction angles phi1And phi2When the nano-bricks are arranged on the base plate, the transmitted light intensity is the same;
when the incident light is linearly polarized light with theta equal to 0 DEG, a set of direction angles phi are obtained1And phi2When the incident light is linearly polarized light with θ being 45 °, another set of direction angles Φ is obtained1And phi2Obtaining four nano brick unit structures with different direction angles;
combining the transmittances corresponding to the nano-brick unit structures at the four direction angles when the incident light is linearly polarized light with theta equal to 0 degrees, and the transmittances corresponding to the nano-brick unit structures at the four direction angles when the incident light is linearly polarized light with theta equal to 45 degrees to obtain four codes;
step 3, the sampling unit comprises t multiplied by t nano brick unit structures, the number of the nano brick unit structures of the transmission part of the sampling unit is changed to control the transmittance of the sampling unit, namely, the light transmission area of the clear aperture is changed to code the amplitude, and meanwhile, the positions of the center of the clear aperture and the center of the sampling unit are changed to code the phase, so that complex amplitude holography is realized;
step 4, designing two holographic films: holographic plate H1And hologram H2Respectively contains M × NGenerating two holograms according to step 3 coding to generate two 0-1 transmittance matrices T of (M T) × (N T) elements1And matrix T2；
The encoding mode of the amplitude and the phase is specifically as follows:
the hologram has M × N sampling units with sampling intervalxAndyeach sampling unit comprises t × t nano brick unit structures with the same size and different direction angles, and then:
x＝y＝t*C
c is the side length of the unit structure substrate;
the complex amplitude of the light wave recorded by the (m, n) th sampling unit on the hologram is set as follows:
wherein A ismnIs normalized amplitude, i.e. 0 ≦ Amn≤1；
Is the phase;
the number of the nano brick unit structures of the sampling unit is kept unchanged, the transmittance of the sampling unit is controlled by changing the number of the nano brick unit structures of the transmission part of the sampling unit, namely, the light transmission area of the clear aperture is changed to code the amplitude, and meanwhile, the positions of the center of the clear aperture and the center of the sampling unit are changed to code the phase, so that complex amplitude holography is realized;
the width of the light-transmitting aperture is WxW is a constant and has a height Lmn yWith normalized amplitude AmnIs in direct proportion; pmn xThe distance between the center of the clear aperture and the center of the sampling unit is in direct proportion to the phase of the sampling unit; the relationship between aperture parameter and complex amplitude is as follows:
Lmn＝Amn，
step 5, matrix T1And matrix T2The element positions of (a) are in one-to-one correspondence, and the matrix T is formed1And matrix T2Simultaneously generating transmission rate coding information, and correspondingly obtaining a direction angle matrix only containing information corresponding to four direction angles according to the coding information in the step 2;
and 6, arranging the nano brick unit structures with the consistent size and the direction angles arranged according to the direction angle matrix at equal intervals in the x direction and the y direction to form the super surface array structure.
2. The method for realizing detour phase encoding multiplexing based on the super-surface array structure as claimed in claim 1, wherein the size parameters of the nano-brick unit structure in step 1 include: the length L, the width W, the height H and the side length C of the unit structure substrate of the nano brick.
3. The method for realizing roundabout phase coding multiplexing based on the super-surface array structure according to claim 1, wherein the orientation angles Φ of the nano-brick unit structures in the step 2 are 22.5 °, 67.5 °, 112.5 ° and 157.5 °, and the incident light is linearly polarized light with θ ═ 0 ° and θ ═ 45 °; the transmittances corresponding to the nano-brick unit structures at the four direction angles are respectively 0, 1 and 1, and when the polarization state of incident linearly polarized light is changed, the transmittances corresponding to the nano-brick unit structures are changed to form four codes of 00, 10, 11 and 01.
4. The method for realizing detour phase encoding multiplexing based on the super surface array structure as claimed in claim 1, wherein the complex amplitude distribution function adopted in step 4 is:
holographic plate H1The complex amplitude distribution of the (m, n) -th sampling unit in (a) is:
holographic plate H2Complex oscillation of the (m, n) -th sampling unit in (1)The web distribution is:
wherein A ismn1And Amn2For holographic disk H1And hologram H2Normalized amplitude of (i.e. 0 ≦ A)mn1≤1，0≤Amn2≤1；
And
for holographic disk H1And hologram H2The phase of (c).
5. The method for realizing detour phase encoding multiplexing based on the super-surface array structure of claim 1, wherein the super-surface array structure in step 6 is composed of a substrate and a nano-brick array etched on the substrate, and the nano-brick array is composed of (M × t) × (N × t) nano-brick unit structures.
6. The method for realizing roundabout phase coding multiplexing based on the super-surface array structure as claimed in claim 5, wherein the substrate material is silicon dioxide, and the nano-brick unit structure material is silver.
7. The method for realizing detour phase encoding multiplexing based on the super-surface array structure as claimed in claim 1, wherein the operating wavelength in step 1 is 633 nm.
8. The method for realizing roundabout phase encoding multiplexing based on the super-surface array structure as claimed in claim 7, wherein when the operating wavelength is 633nm, the length of the nano-brick is 160nm, the width of the nano-brick is 80nm, the height of the nano-brick is 70nm, and the side length of the unit structure substrate is 300 nm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911043883.3A CN110647024B (en) | 2019-10-30 | 2019-10-30 | Method for realizing circuitous phase coding multiplexing based on super-surface array structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911043883.3A CN110647024B (en) | 2019-10-30 | 2019-10-30 | Method for realizing circuitous phase coding multiplexing based on super-surface array structure |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110647024A CN110647024A (en) | 2020-01-03 |
| CN110647024B true CN110647024B (en) | 2020-10-09 |
Family
ID=69013894
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911043883.3A Expired - Fee Related CN110647024B (en) | 2019-10-30 | 2019-10-30 | Method for realizing circuitous phase coding multiplexing based on super-surface array structure |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110647024B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111562707B (en) * | 2020-04-28 | 2022-06-24 | 南京邮电大学 | Roundabout coding design method for superlattice nonlinear imaging process |
| CN113820853B (en) * | 2020-06-18 | 2022-09-23 | 华为技术有限公司 | Method for processing multi-plane optical converter and multi-plane optical converter |
| CN112784467B (en) * | 2021-02-06 | 2022-05-03 | 中国人民解放军国防科技大学 | Programmable super-surface array coding design method for radiation field generation |
| CN114217514B (en) * | 2021-12-22 | 2024-02-02 | 河南工业大学 | Information encryption method based on detour phase and resonance phase hybridization super-structured surface |
| CN114839772B (en) * | 2022-07-04 | 2022-10-21 | 华中科技大学 | Design and implementation method of complex amplitude modulation super-surface device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105974766A (en) * | 2016-05-17 | 2016-09-28 | 南京大学 | Metamaterial capable of realizing acoustic holography based on phase amplitude modulation |
| DE102016100793A1 (en) * | 2016-01-19 | 2017-07-20 | Seereal Technologies S.A. | Method and device for coding complex-valued signals for the reconstruction of three-dimensional objects |
| CN108733924A (en) * | 2018-05-21 | 2018-11-02 | 东南大学 | A kind of intellectualized design method of digital coding metamaterial unit |
| CN110335533A (en) * | 2019-06-19 | 2019-10-15 | 武汉大学 | A kind of optical information hiding method based on super surface array structure |
| CN110380224A (en) * | 2019-07-25 | 2019-10-25 | 东南大学 | A kind of two bit of anisotropic emission formula is difunctional to encode super surface and its design method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103928764B (en) * | 2014-04-11 | 2016-08-17 | 东南大学 | A kind of many bits electromagnetism coding Meta Materials |
| CN110110398B (en) * | 2019-04-19 | 2023-05-12 | 西安工程大学 | Super-surface automatic design method based on convolution self-encoder |
| CN110147022B (en) * | 2019-06-11 | 2020-07-07 | 北京理工大学 | Four-wave mixing holographic multiplexing method based on nonlinear metasurfaces |
-
2019
- 2019-10-30 CN CN201911043883.3A patent/CN110647024B/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102016100793A1 (en) * | 2016-01-19 | 2017-07-20 | Seereal Technologies S.A. | Method and device for coding complex-valued signals for the reconstruction of three-dimensional objects |
| CN105974766A (en) * | 2016-05-17 | 2016-09-28 | 南京大学 | Metamaterial capable of realizing acoustic holography based on phase amplitude modulation |
| CN108733924A (en) * | 2018-05-21 | 2018-11-02 | 东南大学 | A kind of intellectualized design method of digital coding metamaterial unit |
| CN110335533A (en) * | 2019-06-19 | 2019-10-15 | 武汉大学 | A kind of optical information hiding method based on super surface array structure |
| CN110380224A (en) * | 2019-07-25 | 2019-10-25 | 东南大学 | A kind of two bit of anisotropic emission formula is difunctional to encode super surface and its design method |
Non-Patent Citations (1)
| Title |
|---|
| 电磁编码超材料的理论与应用;张磊，刘硕，崔铁军;《中国光学》;20170215;1-12 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110647024A (en) | 2020-01-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110647024B (en) | Method for realizing circuitous phase coding multiplexing based on super-surface array structure | |
| CN108803292B (en) | Polarization multiplexing holographic imaging method based on transmission type all-dielectric super-surface | |
| CN110568528A (en) | Double-mode super surface based on SOI material and double-mode display application thereof | |
| JP2021505942A (en) | 3D beam shaping using metasurface | |
| CN108663740B (en) | Linearly polarized light polarizer based on dielectric nano brick metamaterial and preparation method thereof | |
| CN110794661B (en) | Method for realizing double-channel nano printing and double-channel holography based on laminated super surface | |
| EP0883837A1 (en) | An optical arrangement for processing an optical wave | |
| CN111290063A (en) | Complex amplitude modulated medium-metal double-layer super surface | |
| CN110597022B (en) | Gray scale mask multiplexing technology based on super surface array structure | |
| CN105589203A (en) | Method and device for generating radial polarized array beam | |
| CN111258060B (en) | Super surface design method capable of realizing transflective dual-channel holographic multiplexing | |
| CN110794662B (en) | Design method of amplitude type super surface computer hologram for eliminating zero-order light | |
| CN110361864B (en) | Method for generating Bessel beam array based on Huygens metasurface | |
| CN114690304B (en) | Near-far field double-channel image display method based on super-surface material | |
| CN1322339C (en) | High diffraction efficiency quartz transmission grating with 532 nm wavelength | |
| JP4620220B2 (en) | Computer generated hologram and method for manufacturing the same | |
| CN111399086B (en) | Fork-shaped grating multiplexing method based on super-surface material | |
| CN218037416U (en) | Volume holographic grating preparation system and volume holographic grating | |
| CN1322340C (en) | High diffraction efficiency quartz transmission grating with 1053 nanometer wavelength | |
| JP2004184609A (en) | Method for making computer-generated hologram | |
| CN1322341C (en) | 632.8 nm wavelength high diffraction efficiency quartz transmission grating | |
| Hossfeld et al. | Polarizing computer-generated holograms | |
| CN114895543B (en) | Gray nanometer printing design method based on holographic zero-order and super-surface geometric phase | |
| JP6788622B2 (en) | Diffractive element design method | |
| Sergeev et al. | Diffraction structures formed by two crossed superimposed diffraction gratings |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20201009 Termination date: 20211030 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |