WO2018205762A1

WO2018205762A1 - Terahertz beam splitter

Info

Publication number: WO2018205762A1
Application number: PCT/CN2018/080783
Authority: WO
Inventors: 郑渚; 杨彬; 丁庆
Original assignee: 深圳市太赫兹科技创新研究院; 深圳市太赫兹科技创新研究院有限公司
Priority date: 2017-05-12
Filing date: 2018-03-28
Publication date: 2018-11-15
Also published as: CN107065069A

Abstract

A terahertz beam splitter, which is a Sommerfeld waveguide of a Y-shaped structure. Three ends of the Y-shaped structure are respectively a terahertz coupling end (10) and two terahertz beam-splitting arms (11 and 12). The terahertz coupling end (10) is used for coupling and transmitting an incident terahertz wave. The two terahertz beam-splitting arms (11 and 12) are two branches branching off from the terahertz coupling end (10), and are used for splitting the incident terahertz wave to form two emergent terahertz waves and transmit same. The terahertz wave is transmitted on the surface of the Sommerfeld waveguide by utilising a surface plasma mode of the Sommerfeld waveguide, and the beam splitting of the terahertz wave is realised by means of the two branches of the Y-shaped structure. The terahertz beam splitter has a simple structure, and has the advantages of a large bandwidth, a low loss and a low chromatic dispersion.

Description

Terahertz beam splitter

Technical field

The present invention relates to the field of electromagnetic wave splitting, and more particularly to a terahertz beam splitter.

Background technique

Electromagnetic waves in the terahertz band are more and more widely used due to their own advantages, but limited by the lack of large bandwidth, low loss, low dispersion waveguide structure in the terahertz band, and a large number of terahertz applications are limited to free space optical paths, how to Implementing an integrated terahertz application is a major issue. Among them, the realization of the terahertz wave splitting is the basis of many applications.

At present, due to the difficulty of the waveguide structure, the beam splitter that relies on waveguide transmission in the terahertz frequency band has the disadvantages of high loss and large dispersion, and cannot enjoy the advantages brought by the large bandwidth of the terahertz spectrum.

Summary of the invention

Based on this, it is necessary to provide a terahertz beam splitter with a simple structure, large bandwidth, low loss, and low dispersion.

A terahertz beam splitter, the terahertz beam splitter is a Sommerfeld wave waveguide of a Y-shaped structure, and the three ends of the Y-shaped structure are respectively:

Terahertz coupling end for coupling and conducting terahertz incident waves;

Two terahertz splitting arms, two branches branched from the terahertz coupling end, are used to split the terahertz incident wave into two terahertz outgoing waves and conduct them out.

The terahertz beam splitter is a Sommerfeld wave waveguide of a Y-shaped structure, and the three ends of the Y-shaped structure are a terahertz coupling end and two terahertz splitting arms, respectively, and the terahertz coupling end is used for coupling and conducting the terahertz An incident wave, two terahertz splitting arms are two branches branched from the terahertz coupling end, configured to split the terahertz incident wave into two terahertz outgoing waves and conduct them out; The Hertz beam splitter utilizes the surface plasmon mode of the Sommerfeld wave waveguide, so that the terahertz wave propagates on the surface of the Sommerfeld wave waveguide, and the terahertz wave splitting is realized by two branches of the Y-shaped structure; the terahertz The beam splitter has a simple structure and has the advantages of large bandwidth, low loss, and low dispersion.

In one of the embodiments, the Sommerfeld wave waveguide is a bare metal wire terahertz wave waveguide.

In one embodiment, the terahertz incident wave is a radially polarized terahertz traveling wave transmitted along the terahertz coupling end.

In one of the embodiments, the junction of each of the terahertz beam splitting arms and the terahertz coupling ends forms an arc.

In one of the embodiments, the greater the radius of curvature of the arc, the less the loss of the terahertz splitting arm bend due to bending leakage.

In one embodiment, the Sommerfeld wave waveguide has a bandwidth of 0.1 THz to 5 THz.

In one embodiment, the terahertz coupling end and the two terahertz splitting arms are both cylindrical bare metal wires.

In one embodiment, the bare metal wire is made of gold or silver or copper.

In one embodiment, the bare metal wire is made of stainless steel.

DRAWINGS

1 is a schematic perspective view of a terahertz beam splitter in an embodiment;

2 is a diagram showing the effect of the power division of the terahertz beam splitter in an embodiment;

Figure 3 is a plan view of a terahertz beam splitter in an embodiment;

Figure 4 is a graph showing the power efficiency of a terahertz beam splitter in an embodiment.

detailed description

Referring to FIG. 1, FIG. 1 is a schematic perspective view of a terahertz beam splitter in an embodiment.

In this embodiment, the terahertz beam splitter is a Sommerfeld wave waveguide of a Y-shaped structure, and the three ends of the Y-shaped structure are a terahertz coupling end 10 and two

terahertz splitting arms

11, 12, respectively.

When the Sommerfeld wave waveguide is used to conduct electromagnetic waves in the terahertz band, it operates in a surface plasma mode where terahertz waves propagate on its surface. Further, the Sommerfeld wave waveguide is a bare metal wire terahertz wave waveguide, which can realize surface propagation of a terahertz wave, and has a simple structure, which can transmit a large bandwidth terahertz wave, and the specific Sommerfeld wave waveguide The bandwidth is from 0.1 THz to 5 THz, and the terahertz wave has low loss and low dispersion during propagation through the waveguide.

The terahertz coupling end 10 is used to couple and conduct terahertz incident waves.

The terahertz incident wave enters the Sommerfeld wave waveguide from the terahertz coupling end 10. Further, in order to efficiently couple the terahertz incident wave to the Sommerfeld wave waveguide, the terahertz incident wave adopts a radial polarization (TM01 mode) terahertz traveling wave transmitted along the terahertz coupling end 10.

The two

terahertz splitting arms

11, 12 are two branches branched from the terahertz coupling end 10 for splitting the terahertz incident wave into two terahertz outgoing waves and conducting them out.

The two

terahertz splitting arms

11, 12 and the terahertz coupling end 10 form a Y-shaped structure, wherein the two

terahertz splitting arms

11, 12 are two branches of the Y-shaped structure, and the terahertz incident wave is coupled into the After the Hertz coupling end 10, the two

terahertz splitting arms

11, 12 of the same structure are further propagated to effect splitting. Referring to Fig. 2, Fig. 2 is a diagram showing the effect of the power division of the terahertz beam splitter in an embodiment. The terahertz incident wave enters the terahertz beam splitter from the terahertz coupling end 10, and splits along the surface of the terahertz coupling end 10 to the two

terahertz splitting arms

11, 12 to form a splitting beam to form two field strengths. The weak terahertz exits the wave and continues to propagate along the surface of the terahertz

beam splitting arms

11, 12. The terahertz beam splitter has a simple structure and has the advantages of large bandwidth, low loss, and low dispersion.

Referring to Figure 3, Figure 3 is a top plan view of a terahertz beam splitter in an embodiment. An arc is formed at the junction of each of the terahertz

beam splitting arms

11, 12 and the terahertz coupling end 10. Further, the larger the radius of curvature of the arc, the smaller the loss caused by the bending leakage of the terahertz beam splitting arm.

In the terahertz beam splitter of the Y-shaped structure, the loss of the splitting mainly comes from two aspects: one is the loss due to the mode mismatch and reflection at the bifurcation of the Y-shaped structure; the other is the bending of the metal wire. The resulting terahertz wave leaked. The bifurcation is the junction of the

terahertz splitter arms

11, 12 and the terahertz coupling end 10. Referring to Fig. 4, the length of the arc at the joint is a fixed value of 50 mm, and the radius of the arc corresponding to the fixed arc length varies from 50 mm to 150 mm. By simulation, a single terahertz exit wave and terahertz are obtained when the radius of the arc changes. The field strength relationship of the incident wave. It can be seen that the radius of the arc is gradually increased, that is, the radius of curvature. When the radius R of the arc is greater than 120 mm, the loss caused by the bending leakage of the

terahertz splitting arms

11 and 12 is substantially suppressed, and the single terahertz splitting arm is at this time. The exit field strength of 11, 12 is up to about 55% of the incident field strength, that is, the field strength of the single terahertz outgoing wave is as high as about 55% of the terahertz incident wave. In the splitting structure, the energy utilization efficiency can reach about 2×. (55%) ² = 60.5%.

In one of the embodiments, the terahertz coupling end 10 and the two

terahertz splitting arms

11, 12 are both cylindrical bare metal wires.

In one embodiment, the bare metal wire may be made of gold, silver, copper or stainless steel having high electrical conductivity. It can be selected according to the actual application requirements, and a terahertz beam splitter with simple structure, low cost and low loss is obtained.

The above terahertz beam splitter can be obtained by a machining method or a 3D printing technique.

The terahertz beam splitter adopts a Y-shaped structure of a Sommerfeld wave waveguide, and the three ends of the Y-shaped structure are a terahertz coupling end and two terahertz splitting arms respectively, and a surface plasmon mode using a Sommerfeld wave waveguide So that the terahertz wave propagates on the surface of the Sommerfeld wave waveguide, the terahertz incident wave enters the beam splitter through the terahertz coupling end 10, and the two terahertz splitting arms 11 corresponding to the two branches passing through the Y-shaped structure 12, to achieve splitting, in order to suppress the loss caused by the Y-shaped structure itself, a special arc design is carried out on the bifurcation, which further reduces the loss of the beam splitter and improves its energy utilization. The terahertz beam splitter has a simple structure and has the advantages of large bandwidth, low loss, and low dispersion.

The technical features of the above-described embodiments may be arbitrarily combined. For the sake of brevity of description, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be considered as the scope of this manual.

The above-described embodiments are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims

A terahertz beam splitter, characterized in that the terahertz beam splitter is a Sommerfeld wave waveguide of a Y-shaped structure, and the three ends of the Y-shaped structure are respectively:

Terahertz coupling end for coupling and conducting terahertz incident waves;

Two terahertz splitting arms, two branches branched from the terahertz coupling end, are used to split the terahertz incident wave to form two terahertz outgoing waves and conduct them;

An arc is formed at the junction of each of the terahertz beam splitting arms and the terahertz coupling end, and the larger the radius of curvature of the arc, the smaller the loss due to the bending leakage of the terahertz beam splitting arm.
The terahertz beam splitter according to claim 1, wherein said Sommerfeld wave waveguide is a bare metal wire terahertz wave waveguide.
The terahertz beam splitter according to claim 1, wherein said terahertz incident wave is a radially polarized terahertz traveling wave transmitted along said terahertz coupling end.
The terahertz beam splitter according to claim 1, wherein the Sommerfeld wave waveguide has a bandwidth of 0.1 THz to 5 THz.
The terahertz beam splitter according to claim 2, wherein said terahertz coupling end and said two terahertz splitting arms are cylindrical bare metal wires.
The terahertz beam splitter according to claim 2, wherein the bare metal wire is made of gold or silver or copper.
The terahertz beam splitter according to claim 2, wherein the bare metal wire is made of stainless steel.