KR20190019396A - Ultra-thin circular polarization analyzer integrated meta surface and plasmon photodetector - Google Patents

Abstract

Provided is a circular polarization analyzer to analyze a polarization direction of circular polarization with a meta surface and a photodetector. Moreover, the circular polarization incident on the meta surface is spread toward the photodetector in the shape of a surface electromagnetic wave, and the photodetector is used to measure a photoelectric current by the surface electromagnetic wave to analyze the polarization direction of the incident circular polarization.

Description

TECHNICAL FIELD [0001] The present invention relates to an ultra-thin film circular polarized light analyzer having a meta surface and a plasmon photodetector integrated therein,

The present invention relates to a circularly polarized analyzer that analyzes whether a circularly polarized light is a right-handed circularly polarized light or a left-handed circularly polarized light.

Meta material is a material designed to have characteristics not found in nature. It consists of a collection of repeating composite elements formed from common materials such as plastics and metals. The properties of a metamaterial are determined not by their intrinsic properties but by their shape, geometry, size, orientation and arrangement. Properly designed metamaterials interfere with electromagnetic waves or sound, making certain objects inaccessible. Typically, metamaterials have negative refractive indices. Unlike the phenomenon of nature, it refracts light at a negative angle and wants to have the property of amplifying the evanescent wave inversely.

The meta surface is a two-dimensional single thin film surface produced from a metamaterial and made in consideration of the difficulty and cost of the metamaterial technology that is stacked in three dimensions. The meta surface is more suitable for the current process based on the thin film structure, and has the advantage that the material showing various properties can be realized through the thin film structure. The meta-surface maintains the basic shape of the unit structure of the thin film, and displays various characteristics by adjusting the rotation angle of the unit structure and relative position information between the structures on a cycle unit basis.

Plasmon is a phenomenon in which electrons in a material vibrate at the same time and are called waves of electrons. There are many free electrons inside the conductor, and electrons that are not bound to metal easily react by external stimulation.

Surface plasmon is a collective charge density oscillation of electrons occurring on the surface of a metal thin film, and the surface plasmon waves are surface electromagnetic waves traveling along the interface between the metal and the dielectric material adjacent thereto.

Current optical systems occupy a large amount of physical space, and many optics are precisely arranged. Due to these factors, it is very difficult to miniaturize an optical system having various functions, and the cost of miniaturization is very small. In recent years, meta materials or meta surfaces have emerged to overcome these limitations of optical systems.

In particular, a device having various functions has been implemented using a meta surface, which is a structure made of a thin film. However, until now, it has been limited to passive device development, and active optical devices in which the meta surface is actually integrated have not been realized.

An embodiment according to the present invention provides a circularly polarized light analyzer which can be used in an optical apparatus in which a meta-surface and a plasmon photodetector are integrated and miniaturized, and a manufacturing method thereof.

One embodiment of the present invention provides a circularly polarized light analyzer for analyzing a polarization direction by converting a surface plasmon into a photocurrent in a photodetector when the circularly polarized light incident on the meta surface propagates in a surface plasmon form, and a method of manufacturing the same .

A circular polarization analyzer according to the present invention comprises a bottom metal plate; Upper metal plate; At least one meta surface disposed on at least a portion of the upper metal plate and patterned to generate surface electromagnetic waves traveling in different directions according to the polarization direction of the incident circularly polarized light; A dielectric disposed between the bottom metal plate and the top metal plate and through which the surface electromagnetic waves at least partially pass; And at least one photodetector for converting the surface electromagnetic wave into an electrical signal for detection.

The at least one meta-surface generates electromagnetic waves having a constructive interference or an attenuating interfering planar wave when the circularly polarized light is incident, and a linear double orthogonal slit is formed in order to change the traveling direction of the plane wave in accordance with the polarization direction of the circularly polarized light Can be patterned.

Furthermore, the at least one photodetector may be located in the traveling direction of the plane waveform.

The at least one meta-surface generates electromagnetic waves of a circularly-shaped interference interference or attenuating interference when the circularly polarized light is incident, and a helical double orthogonal slit is formed in order to change the traveling direction of the circular wave- form according to the polarization direction of the circularly polarized light Can be patterned.

Furthermore, the at least one photodetector may be located in the traveling direction of the circular waveform.

The dielectric may have a thickness to at least partially form a single mode optical waveguide capable of generating only a single surface electromagnetic wave.

A method of manufacturing a circularly polarized light analyzer according to the present invention includes: forming a photodetector on at least a portion of a substrate; Forming a waveguide by coating a dielectric on the substrate as a whole; Depositing a first metal plate on the waveguide; Removing the substrate and depositing a second metal plate on the removed portion; And patterning a meta surface on at least a portion of the second metal plate to generate surface electromagnetic waves traveling in different directions depending on the polarization direction of the incident circularly polarized light.

The step of coating the dielectric may include coating a dielectric having a thickness that at least partially forms a single mode optical waveguide capable of generating only a single surface electromagnetic wave.

Wherein the step of patterning the meta surface on at least a portion of the second metal plate comprises the steps of generating an electromagnetic wave of a constructive interference or a planar interfering interference wave when the circularly polarized light is incident, And patterning a linear double orthogonal slit on at least a portion of the second metal plate to cause the second metal plate to vary.

Further, forming the photodetector on at least a portion of the substrate may include forming the photodetector on at least a portion of the substrate such that the photodetector is positioned in the direction of travel of the planar waveguide.

Wherein the step of patterning the meta surface on at least a portion of the second metal plate comprises the steps of generating an electromagnetic wave of a circularly polarized interference or interference interference pattern when the circularly polarized light is incident on the polarizing direction of the circularly polarized light, And patterning a spiral dual orthogonal slit on at least a portion of the second metal plate to cause the second metal plate to vary.

Further, forming the photodetector on at least a portion of the substrate may include forming the photodetector on at least a portion of the substrate such that the photodetector is positioned in the direction of travel of the circular waveform.

The circular polarized light analyzer according to the present invention can be manufactured by the circular polarized light analyzer manufacturing method.

The circularly polarized light analyzer and the method of manufacturing the same according to the present invention can be used in an optical apparatus in which a meta-surface and a plasmon photodetector are integrated and miniaturized.

The circularly polarized light analyzer and its manufacturing method according to the present invention can analyze the polarization direction by converting a surface plasmon into a photocurrent in a photodetector when the circularly polarized light incident on the meta surface propagates in the form of a surface plasmon.

1 is a schematic diagram of a circular polarization analyzer including a meta surface patterned with a linear dual orthogonal slit in accordance with an embodiment of the present invention.
2 is a schematic diagram of a circularly polarized light analyzer including a meta-surface patterned with a spiral dual orthogonal slit in accordance with an embodiment of the present invention.
Fig. 3 is a view for explaining the polarization of light.
4 is a view for explaining destructive interference or constructive interference due to a meta surface patterned with a linear double orthogonal slit.
5 is a view for explaining surface electromagnetic waves generated according to the principle of FIG.
6 is a diagram for explaining destructive interference or constructive interference by a meta-surface patterned with a spiral dual orthogonal slit.
7 is a view showing surface electromagnetic waves generated according to the principle of FIG.
8 is a view for explaining a method of manufacturing a circularly polarized light analyzer according to an embodiment of the present invention.
9 is a graph of the current intensity according to the circular polarization direction measured in a circular polarization analyzer including a meta surface patterned with a linear double orthogonal slit and having one photodetector.
10 is a graph of the current intensity according to the circular polarization direction measured in a circular polarization analyzer including a meta surface patterned with a linear double orthogonal slit and having two photodetectors.
11 is a graph of the current intensity along the circular polarization direction measured in a circular polarization analyzer including a meta surface patterned with a spiral dual orthogonal slit.

Hereinafter, specific embodiments among various embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, this specific embodiment does not limit or limit the invention. The same reference numerals denote the same elements regardless of the reference numerals in the drawings, and a duplicate description will be omitted.

1 is a schematic diagram of a circular polarization analyzer including a meta surface patterned with a linear dual orthogonal slit in accordance with an embodiment of the present invention.

Referring to FIG. 1, a circularly polarized light analyzer includes an upper metal plate 110, a lower metal plate 120, a dielectric 130, a meta surface 160, and a photodetector 170.

The circularly polarized light 140 may be right-handed circularly polarized light or left-polarized light, i.e., left-handed circularly polarized light.

The meta surface 160 is a surface that is patterned in the shape of a linear, double orthogonal slit on the top metal plate 110. When the circularly polarized light 140 is incident on the meta surface 160, the surface plasmon, that is, the surface electromagnetic wave 150 propagates through the gap between the upper metal plate 110 and the dielectric material 130.

As shown in FIG. 1, when the meta surface 160 is patterned in the shape of a linear double orthogonal slit, the surface electromagnetic wave 150 propagates in a single direction in a direction perpendicular to the straight line.

The surface electromagnetic wave 150 is generated by each of the linear double orthogonal slits, and constructive interference or destructive interference occurs based on the interval between the slits, the interval between the slit lines, the wavelength of the surface electromagnetic wave, the thickness of the dielectric,

In one example, when a right-handed circularly polarized light is vertically incident on a patterned meta-surface in the form of a linearly bi-orthogonal slit, constructive interference occurs in the left portion of the straight, double orthogonal slit, However, in the right part, destructive interference may occur and surface electromagnetic waves may not propagate.

When the left-handed circularly polarized light is vertically incident on the patterned meta-surface in the form of a linear double-orthogonal slit, the right-hand portion of the straight double-orthogonal slit can propagate surface electromagnetic waves due to constructive interference , Destructive interference occurs in the left part, and surface electromagnetic waves may not propagate.

That is, when a right-handed circularly polarized light is vertically incident on a patterned meta-surface in the form of a linear double-orthogonal slit, the surface electromagnetic wave can propagate in the left direction perpendicular to the straight line, left-handed circularly polarized light is incident vertically on a patterned meta-surface in the form of a linear double-sided slit, the surface electromagnetic wave can propagate to the right, perpendicular to the straight line.

The photodetector 170 converts the propagating surface electromagnetic wave 150 into an electrical signal.

It is possible to determine the polarization direction of the circularly polarized light by judging from which position the electric signal is detected in the photodetector.

For example, when a right-handed circularly polarized light is vertically incident on a patterned meta-surface in the form of a linear, double-orthogonal slit, the photodetector located on the left of the meta surface, An electrical signal is detected, but no electrical signal is detected in the photodetector disposed on the right side.

When a left-handed circularly polarized light is incident vertically on a patterned meta-surface in the form of a linearly-biased orthogonal slit, since the surface electromagnetic wave propagates to the right, in the photodetector disposed on the right side of the meta surface, However, in the photodetector disposed on the left side, an electrical signal is not detected.

The photodetector 170 may be a semiconductor photodiode such as a PN photodiode, a Positive-Intrinsic-Negative (PIN) photodiode, an Avalanche photodiode, or the like.

The photodetector 170 may be electrically connected to the upper metal plate 110 and the lower metal plate 120 to detect surface electromagnetic waves and transmit the converted electrical signals to an external device.

The dielectric 130 is present between the upper metal plate 110 and the lower metal plate 120 and a waveguide along which the surface electromagnetic waves propagate can be formed together with the upper metal plate 110. Dielectric 130 may be, for example, benzocyclobutene (BCB). The mode of surface electromagnetic waves propagating to the thickness of the dielectric can be changed. In order to generate a single-mode surface electromagnetic wave, the dielectric thickness can be determined using a finite difference time domain (FDTD) method. In one example, when dielectric 130 is benzocyclobutene, the thickness of the dielectric can be set to 500 nm by the FDTD technique.

2 is a schematic diagram of a circularly polarized light analyzer including a meta-surface patterned with a spiral dual orthogonal slit in accordance with an embodiment of the present invention.

Referring to FIG. 2, the meta surface 210 is a spiral, double slit patterned surface on the top metal plate 110.

When the circularly polarized light 140 is incident on the meta surface 160, the surface plasmon, that is, the surface electromagnetic wave 150 propagates through the gap between the upper metal plate 110 and the dielectric material 130.

As shown in FIG. 2, when the meta surface 160 is patterned in the form of a helical double orthogonal slit, the surface electromagnetic wave 150 propagates in the radial direction of the helix. The surface electromagnetic wave 150 is generated by each of the helical double orthogonal slits, and constructive interference or destructive interference occurs based on the interval between the slits, the interval between the spirals, the wavelength of the surface electromagnetic wave, the thickness of the dielectric,

In one example, when a right-handed circularly polarized light is vertically incident on a patterned meta-surface in the form of a spirally-biased orthogonal slit, surface interference may occur due to constructive interference in the interior of the helix , Destructive interference may occur in the outer portion, and surface electromagnetic waves may not propagate.

When the left-handed circularly polarized light is vertically incident on the patterned meta-surface in the form of a helical double orthogonal slit, the surface electromagnetic waves may propagate due to constructive interference at the outer portion of the helix, Destructive interference may occur and surface electromagnetic waves may not propagate.

That is, when a right-handed circularly polarized light is vertically incident on a patterned meta-surface in the form of a helical double orthogonal slit, the surface electromagnetic wave can propagate inward in the spiral radial direction, and the left circularly polarized light When a circularly-handled circularly polarized light is vertically incident on a patterned meta-surface in the form of a spirally bi-orthogonal slit, the surface electromagnetic wave can propagate outward in the spiral radial direction.

The photodetector 220 converts the propagating surface electromagnetic wave 150 into an electrical signal.

It is possible to determine the polarization direction of the circularly polarized light by judging from which position the electric signal is detected in the photodetector.

For example, when a right-handed circularly polarized light is incident vertically on a patterned meta surface in the form of a spiral, double orthogonal slit, the surface electromagnetic waves propagate inward in the spiral radial direction, An electrical signal is detected in the photodetector, but no electrical signal is detected in the photodetector disposed outside the radius.

When a left-handed circularly polarized light is incident vertically on a patterned meta-surface in the form of a helical double orthogonal slit, since the surface electromagnetic wave propagates outward in the spiral radial direction, An electric signal is detected, but an electric signal is not detected in the photodetector disposed inside the intrinsic radius.

Fig. 3 is a view for explaining the polarization of light.

In the traveling electromagnetic wave, the vectors of the electric field and the magnetic field are perpendicular to each other. Therefore, electromagnetic waves can be explained using only an electric field. the x-axis component and the y-axis component in the electric field traveling in the z-axis direction can be expressed by the following relational expressions 1 and 2.

(Relational expression 1)

(Relational expression 2)

및

가 1로 동일할 때,

가

이면 전기장이 진행함에 따라 시계 방향으로 회전하고, 이를 좌원형 편광이라고 한다.

가 -

이면 전기장이 진행함에 따라 반시계 방향으로 회전하고, 이를 우원형 편광이라고 한다.In Figure 3, the direction of the electric field is the direction through the ground. As shown in Figure 3,

And

Is equal to 1,

end

And it rotates in a clockwise direction as the electric field advances, which is called a left circularly polarized light.

In addition,

As the electric field progresses, it rotates in a counterclockwise direction, and this is called circular polarization.

4 is a view for explaining destructive interference or constructive interference due to a meta surface patterned with a linear double orthogonal slit.

의 1/4배일 수 있다. 이 경우, 제1 슬릿(410)에 의해 진행하는 표면 전자기파와 제2 슬릿(420)에 의해 진행하는 표면 전자기파 간에는

만큼 위상 차가 발생한다.Referring to FIG. 4, the first slit 410 of the double orthogonal slit is inclined by 135 ° with respect to the horizontal line, the second slit 420 is inclined by 45 °, and the first slit and the second slit are inclined by 90 ° . The first slit 410 and the second slit 420 receive circularly polarized light and generate surface electromagnetic waves that propagate to the waveguide between the meta surface and the dielectric. The interval between the first slit 410 and the second slit 420 can be set so that the traveling direction of the surface electromagnetic wave is determined in accordance with the polarization direction of the circularly polarized light. For example, as shown in FIG. 4, the interval S between the first slit 410 and the second slit 420 is the surface electromagnetic wave wavelength

/ RTI > In this case, between the surface electromagnetic wave propagated by the first slit 410 and the surface electromagnetic wave propagated by the second slit 420

Phase difference occurs.

4, when a linearly polarized light is incident on the meta surface, surface electromagnetic waves generated by the first slit 410 and the second slit 420 have the same intensity and are transmitted through the first slit 410 And the right side of the second slit 420, as shown in Fig.

When the left circularly polarized light is incident on the meta surface, a phase difference occurs due to the inter-slit interval S, and on the left side of the first slit 410, destructive interference occurs due to the phase difference, and surface electromagnetic waves are not propagated. On the right side of the second slit 420, constructive interference occurs due to the phase difference, and the surface electromagnetic wave propagates. Therefore, in the photodetector located on the left side of the first slit 410, an electrical signal is not detected but in the photodetector located on the right side of the second slit 420, an electrical signal is detected.

When the right circularly polarized light enters the meta surface, a phase difference occurs due to the inter-slit interval S, and on the left side of the first slit 410, a constructive interference occurs due to a phase difference, and surface electromagnetic waves propagate. On the right side of the second slit 420, destructive interference occurs due to the phase difference, and surface electromagnetic waves are not propagated. Therefore, in the photodetector positioned on the left side of the first slit 410, an electrical signal is detected, but in the photodetector positioned on the right side of the second slit 420, no electrical signal is detected.

5 is a view for explaining surface electromagnetic waves generated according to the principle of FIG.

The first slit 410, which is inclined at 135 ° with respect to the horizontal line, and the second slit 420, which is inclined at 45 °, alternate with each other at 90 ° to the meta surface 510 patterned with the linear dual orthogonal slits And are arranged in a straight line. As shown in the meta surface 510, such a straight line may be arranged in at least one or more rows.

530 and 540, respectively, showing the intensity of the surface electromagnetic wave are a diagram 520 when linearly polarized light is incident, a diagram 530 when left circularly polarized light is incident, a diagram 530 when a right-handed circularly polarized light is incident (540).

In the diagram 520 when the linearly polarized light is incident, the surface electromagnetic waves propagate with similar intensity in the left and right directions of the meta surface. Since the surface electromagnetic wave has a property of rapidly decreasing intensity along the distance, the photodetector can be disposed close to the meta surface in order to detect surface electromagnetic waves. A circular polarization analyzer including a meta surface and a photodetector can be integrated within several tens of micrometers, and thus can be used in various optical devices.

In the figure 530 where the left circularly polarized light is incident, the surface electromagnetic wave in the right direction of the meta surface has a reinforced intensity and the surface electromagnetic wave in the left direction has a destructive interference intensity. Therefore, The signal is not detected, and in the photodetector disposed on the right side, an electrical signal is detected.

Since the surface electromagnetic wave in the left direction of the meta surface has the intensity strengthened and the surface electromagnetic wave in the right direction has the destructive interference intensity in the figure 540 when the right circularly polarized light is incident, And an electrical signal is detected in the photodetector disposed on the left side.

6 is a diagram for explaining destructive interference or constructive interference by a meta-surface patterned with a spiral dual orthogonal slit.

Referring to FIG. 6, the radius of the helix can be expressed by the following relational expression 3.

(Relational expression 3)

는 시계방향으로 커지는 각도이다. 우원형 편광인 경우 r0는 나선의 가장 큰 반경이고,

는 반시계방향으로 커지는 각도이다.In the case of the left circularly polarized light, r0 is the smallest radius,

Is an angle that increases in the clockwise direction. In the case of right circularly polarized light, r0 is the largest radius of the helix,

Is an angle that increases in the counterclockwise direction.

, C 지점에서 발생하는 표면 전자 기파의 위상은

이다. 이 때, 각 지점에서 나선의 중심으로 진행하는 표면 전자기파는 나선의 각 지점으로부터 나선의 중심까지 각 지점 에서의 나선 반경만큼의 거리를 진행한다. 예를 들어, A 지점에서 발생하는 표면 전자기파는 r0만큼의 거리, B 지점에서 발생하는 표면 전자기파는

만큼의 거리, C 지점에서 발생하는 표면 전자기파는

만큼의 거리를 진행한다. 진행한 거리만큼 위상의 변화가 발생하므로, 좌원형 편광이 입사하는 경우 나선의 중심에서는 상쇄 간섭이 발생한다. 우원형 편광이 입사한 경우(620), A' 지점에서 발생하는 표면 전자기파의 위상을 0이라고 하면, B' 지점에서 발생하는 표면 전자기파의 위상은

, C' 지점에서 발생하는 표면 전자 기파의 위상은

이다. 이 때, 각 지점에서 나선의 중심으로 진행하는 표면 전자기파는 나선의 각 지점으로부터 나선의 중심까지 각 지점 에서의 나선 반경만큼의 거리를 진행한다. 예를 들어, A' 지점에서 발생하는 표면 전자기파는 r0만큼의 거리, B' 지점에서 발생하는 표면

전자기파는

만큼의 거리, C' 지점에서 발생하는 표면 전자기파는

만큼의 거리를 진행한다. 진행한 거리만큼 위상의 변화가 발생하므로, 우원형 편광이 입사하는 경우 나선의 중심에서는 보강 간섭이 발생한다.The circularly polarized light incident on the helical meta surface is converted to the surface electromagnetic wave form at each slit of the helical meta surface and proceeds to the center of the helix. The surface electromagnetic waves propagating in each slit have different phases. For example, if the left circularly polarized light is incident (610) and the phase of the surface electromagnetic wave generated at the point A is 0, then the phase of the surface electromagnetic wave generated at the point B is

, The phase of the surface electromagnetic wave generated at point C is

to be. At this point, the surface electromagnetic waves traveling to the center of the helix at each point proceed from the point of each helix to the center of the helix by the helix radius at each point. For example, the surface electromagnetic wave generated at point A is a distance of r0, the surface electromagnetic wave generated at point B is

, The surface electromagnetic waves generated at the point C

. A phase change is generated by the distance that has been progressed. Therefore, when the left circularly polarized light is incident, destructive interference occurs at the center of the helix. When the right circularly polarized light is incident (620), if the phase of the surface electromagnetic wave generated at the point A 'is 0, the phase of the surface electromagnetic wave generated at the point B'

, The phase of the surface electromagnetic wave generated at point C '

to be. At this point, the surface electromagnetic waves traveling to the center of the helix at each point proceed from the point of each helix to the center of the helix by the helix radius at each point. For example, the surface electromagnetic wave generated at point A 'is a distance of r0, the surface at point B'

Electromagnetic waves

, The surface electromagnetic wave generated at the point C '

. Since the phase changes as much as the progressed distance, constructive interference occurs at the center of the helix when right circularly polarized light is incident.

7 is a view showing surface electromagnetic waves generated according to the principle of FIG.

The meta surface 710 patterned with the spiral dual orthogonal slits is arranged in a spiral shape with alternating first slits and second slits 90 ° at an angle of 90 °. These helical slits may be arranged to rotate at least once.

Each of the diagrams 720 and 730 showing the intensity of the surface electromagnetic wave shows a diagram 720 when the left circularly polarized light is incident and a diagram 730 when the right circularly polarized light is incident.

In the figure 720 when the left circularly polarized light is incident, the surface electromagnetic wave inside the radial echo of the helical meta surface has the interfering intensity and the outer surface electromagnetic wave has the destructive interference intensity, , An electrical signal is not detected and an optical signal is detected in the photodetector disposed inside.

In Figure 730 where the right circularly polarized light is incident, the surface electromagnetic wave radially outward of the helical meta surface has the interfering intensity and the surface electromagnetic wave in the inner direction has the canceled interference intensity, An electrical signal is not detected and an electrical signal is detected in the photodetector disposed outside.

A circular polarization analyzer including a meta surface and a photodetector can be integrated within several tens of micrometers, and thus can be used in various optical devices.

8 is a view for explaining a method of manufacturing a circularly polarized light analyzer according to an embodiment of the present invention.

At S810, a semiconductor material corresponding to the material of the photodetector may be grown on the first substrate to form a photodetector. For example, InGaAs or InAlGaAs, which is a material of the photodetector, can be grown on a first substrate of indium phosphide. The growth method includes, for example, at least one of molecular beam epitaxy growth, vapor phase epitaxy growth, and liquid chamfer epitaxy growth .

At S820, an insulating material may be deposited on the semiconductor material. For example, silicon dioxide may be deposited on InGaAs or InAlGaAs, a semiconductor material. The method of depositing may include, for example, plasma enhanced chemical vapor deposition (PECVD).

At S830, a semiconductor material may be patterned to form a photodetector on the first substrate. The method of patterning may include, for example, at least one of dry etching, wet etching, electron beam lithography, ultraviolet lithography, and visible light lithography.

At S840, the dielectric may be coated on the first substrate to at least partially form the waveguide. Since the mode of the surface electromagnetic wave can be determined according to the thickness of the dielectric, the thickness of the dielectric can be determined using a finite difference time domain method (FDTD) to form a single mode surface electromagnetic wave. For example, benzocyclobutene (BCB) having a thickness of 500 nm can be coated on the first substrate using FDTD. Considering the thickness of the dielectric, the thickness of the metal, the wavelength of the surface electromagnetic wave, etc. in addition to the benzocyclobutene, a dielectric material capable of generating a single mode surface electromagnetic wave can be coated on the first substrate.

At S850, the top of the coated dielectric may be planarized to deposit a metal layer on the coated dielectric. The planarization method may include, for example, mechanical-chemical planarization (CMP).

At S860, a bottom metal layer may be deposited on the planarized dielectric. The deposition method may include, for example, plasma enhanced chemical vapor deposition (PECVD).

In S870, the lower metal layer may be positioned below and the lower metal layer and the second substrate may be bonded. The bonding method may include at least one of, for example, thermocompression bonding and ultrasonic bonding.

At S880, the first substrate may be removed to deposit the upper metal layer. The method of removing the substrate can include, for example, a laser lift-off method or a selective etching method.

In S890, an upper metal layer may be deposited on the portion where the first substrate is removed, and the meta surface may be patterned. For example, the upper metal layer may include at least one of, for example, gold (Au), silver (Ag), aluminum (Al), and copper (Cu). The method of patterning the meta surface may include at least one of a Foucused Ion Beam (FIB) milling method and an E-beam lithography method, for example.

9 is a graph of the current intensity according to the circular polarization direction measured in a circular polarization analyzer including a meta surface patterned with a linear double orthogonal slit and having one photodetector.

Referring to FIG. 9, the photodetector of the circularly polarized light analyzer can be disposed on the right side of the meta surface. When the left circularly polarized light is incident on the meta surface, a constructive interference of the surface electromagnetic wave occurs on the right side of the meta surface, so that a relatively larger current is detected than when the right circularly polarized light is incident on the meta surface. The graph of FIG. 9 is obtained by measuring the photocurrent detected by the photodetector while changing the polarization direction of the circularly polarized light vertically incident on the meta surface patterned with the linear double orthogonal slit at intervals of 10 seconds. The photocurrent is not detected in the OFF state in which no polarized light is incident on the meta surface. A photocurrent of about 0.89μA flows when the right circularly polarized light is incident perpendicularly to the meta surface, and a photocurrent of about 2.75μA flows when the left circularly polarized light is incident perpendicularly to the meta surface. That is, the circular polarization analyzer according to the present invention can detect the polarization direction of the circularly polarized light by detecting the intensity of the current by the circularly polarized light. In one example, another photodetector may be placed on the left side of the meta surface to increase the detection performance by measuring the current.

10 is a graph of the current intensity according to the circular polarization direction measured in a circular polarization analyzer including a meta surface patterned with a linear double orthogonal slit and having two photodetectors.

Referring to FIG. 10, the circular polarization analyzer may include a left optical detector 1010 and a right optical detector 1020. The left photodetector 1010 detects a large photocurrent when the right circularly polarized light is incident on the meta surface and the right photodetector 1020 can detect a large photocurrent when the left circularly polarized light is incident on the meta surface. The graph of FIG. 10 shows the photocurrent detected at the left photodetector 1010 and the right photodetector 1020. The circularly polarized light is incident at a different polarization direction every 10 seconds. In the OFF state in which no polarized light is incident, no photocurrent is detected in both the left and right photodetectors. When the left circularly polarized light is incident vertically on the meta surface, the right photodetector 1020 detects a relatively large photocurrent while the left photodetector 1010 can detect a relatively small photocurrent. When the right circularly polarized light is incident perpendicular to the meta surface, the right photodetector 1020 detects a relatively small photocurrent while the left photodetector 1010 can detect a relatively large photocurrent.

11 is a graph of the current intensity along the circular polarization direction measured in a circular polarization analyzer including a meta surface patterned with a spiral dual orthogonal slit.

Referring to FIG. 11, the photodetector of the circularly polarized light analyzer is disposed radially inward of the helical meta-surface. When the left circularly polarized light is incident on the meta surface, a constructive interference of the surface electromagnetic wave occurs in the radial direction of the meta surface, so a relatively larger current is detected than when the right circularly polarized light is incident on the meta surface. The graph of FIG. 11 is obtained by measuring the photocurrent detected by the photodetector while changing the polarization direction of the circularly polarized light vertically incident on the meta surface patterned with the spiral dual orthogonal slit at intervals of 10 seconds. The photocurrent is not detected in the OFF state in which no polarized light is incident on the meta surface. In the case where right circularly polarized light enters perpendicularly to the meta surface, it can be seen that a photocurrent is 75% smaller than when the left circularly polarized light is incident perpendicularly on the meta surface. In one example, another photodetector may be further disposed radially outwardly of the meta surface to increase the detection performance.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (10)

Bottom metal plate;
Upper metal plate;
At least one meta surface patterned on the top metal plate to generate surface electromagnetic waves traveling in a specific direction determined by the polarization direction of the incident circularly polarized light;
A dielectric disposed between the bottom metal plate and the top metal plate and through which the surface electromagnetic waves at least partially pass; And
At least one photodetector for converting the surface electromagnetic wave into an electrical signal for detection;
And a polarization analyzer. The method according to claim 1,
The at least one meta surface
A linear double orthogonal slit is patterned in order to generate surface electromagnetic waves with a reinforcing interference or a plane wave interfered with the polarization direction of the incident circularly polarized light and to change the traveling direction of the surface electromagnetic wave according to the polarization direction of the circularly polarized light Wherein the circular polarization analyzer is a circular polarization analyzer. The method according to claim 1,
The at least one meta surface
In order to generate surface electromagnetic waves of a circularly shaped waveform in which the interference interference or attenuation interference is caused by the polarization direction of the incident circularly polarized light and to make the direction of the surface electromagnetic wave to be changed in accordance with the polarization direction of the incident circularly polarized light, Wherein the circular polarization analyzer is a circular polarization analyzer. The method according to claim 3 or 4,
The at least one photodetector
And wherein the analyzer is located in a traveling direction of the surface electromagnetic wave. The method according to claim 1,
The dielectric
And has a thickness for at least partially forming a single mode optical waveguide capable of generating only a single surface electromagnetic wave. Forming a photodetector on at least a portion of the substrate;
Coating a dielectric on the substrate as a whole;
Depositing a first metal plate on the waveguide;
Removing the substrate and depositing a second metal plate on the removed portion; And
Patterning a meta surface on the second metal plate to generate surface electromagnetic waves traveling in different directions according to the polarization direction of the incident circularly polarized light
Wherein the circular polarization analyzer comprises a plurality of circular polarization analyzers. The method according to claim 6,
The step of coating the dielectric
Coating a dielectric having a thickness to at least partially form a single mode optical waveguide capable of generating only a single surface electromagnetic wave
Wherein the circular polarization analyzer comprises a plurality of circular polarization analyzers. The method according to claim 6,
The step of patterning the meta surface on the second metal plate
A linear double orthogonal slit for generating a surface electromagnetic wave of a planar wave having a constructive interference or a damped interference by the polarization direction of the incident circular polarized light and for changing the traveling direction of the surface electromagnetic wave according to the polarization direction of the circular polarized light, A step of patterning on a metal plate
Wherein the circular polarization analyzer comprises a plurality of circular polarization analyzers. The method according to claim 6,
Wherein patterning the meta surface on at least a portion of the second metal plate comprises:
A spiral dual orthogonal slit for generating surface electromagnetic waves of a circularly-shaped interference interference or attenuating interference by the polarization direction of the incident circularly polarized light and for changing the traveling direction of the surface electromagnetic wave according to the polarization direction of the incident circularly polarized light, A step of patterning on a metal plate
Wherein the circular polarization analyzer comprises a plurality of circular polarization analyzers. 10. The method according to claim 8 or 9,
The step of forming a photodetector on at least a portion of the substrate
Forming the photodetector on at least a portion of the substrate such that a photodetector is positioned in a traveling direction of the circular waveform
Wherein the circular polarization analyzer comprises a plurality of circular polarization analyzers.

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