CN103457009A - Terahertz low-loss bent waveguide - Google Patents

Abstract

The invention relates to a terahertz low-loss curved waveguide, which includes an outer waveguide plate and an inner waveguide plate, both of which are curved metal plates with arc-shaped curved parts, and the outer waveguide plate and the inner waveguide plate They are arranged in parallel with a distance from each other, and periodic grooves are respectively provided on the opposite surfaces of the outer waveguide plate and the inner waveguide plate. The terahertz wave is input from one end of the outer waveguide plate and the inner waveguide plate in the transverse magnetic wave mode, enters the gap between the outer waveguide plate and the inner waveguide plate, forms a surface wave and transmits in the gap, and then transmits to the outer waveguide plate and the inner waveguide The other end of the plate, thus realizing the low-loss bending transmission of terahertz waves. According to the technical solution of the present invention, not only the bending loss of the terahertz wave is low, but also the structure is simple, the use is convenient, and the cost is low.

Description

Terahertz low-loss curved waveguide

technical field

The invention relates to a terahertz low-loss curved waveguide.

Background technique

Terahertz (THz) waves are electromagnetic waves that lie between microwaves and far infrared rays. In recent years, with the development of ultrafast laser technology, the generation of terahertz pulses has a stable and reliable excitation light source, enabling people to study terahertz. Terahertz has a wide range of applications in biomedicine, safety monitoring, non-destructive detection, astronomy, spectroscopy and imaging technology, and information science. Terahertz waveguide is a basic transmission device for terahertz applications and a key device for terahertz communication systems. Internationally, Maier et al. studied the propagation characteristics of terahertz waves on structured metal surfaces in 2008 (Nature Photonics, 2, 175-179, 2008), and Nahata et al. studied pseudo-surface plasmon waveguides on rectangular groove arrays in 2011 ( Optics Express, 19, 1072-1080, 2011), but the lateral electrical dimensions of all these structures are large, resulting in large losses in the case of bending.

Contents of the invention

The purpose of the present invention is to overcome the defect that the above-mentioned existing waveguide has relatively large loss in the case of bending.

In order to achieve this purpose, the present invention provides a terahertz low-loss curved waveguide, which includes an outer waveguide plate and an inner waveguide plate, both of which are curved metal plates and the curved portion is arc-shaped, The outer waveguide plate and the inner waveguide plate are arranged in parallel with a distance from each other, and periodic grooves are respectively provided on the opposite surfaces of the outer waveguide plate and the inner waveguide plate.

Preferably, the metal material of the outer waveguide plate and the inner waveguide plate is one of aluminum, copper, silver, iron, and nickel.

According to a preferred embodiment of the present invention, the bending angle of the waveguide is a right angle, and the bending radius is greater than 500 μm.

According to a preferred embodiment of the present invention, the outer waveguide plate and the inner waveguide plate are similar in shape, and the grooves on the outer waveguide plate and the grooves on the inner waveguide plate have the same size and interval.

According to a preferred embodiment of the present invention, the grooves on the outer waveguide plate and the grooves on the inner waveguide plate are symmetrical about the center line between the outer waveguide plate and the inner waveguide plate.

According to a preferred embodiment of the present invention, the width of the groove is 50-500 μm, the depth is 50-500 μm, and the length is not less than 500 μm; the width of the groove is preferably 152 μm, and the depth is preferably 274 μm.

According to a preferred embodiment of the present invention, the periodic interval of the grooves is preferably 475 μm.

According to a preferred embodiment of the present invention, the arc radii of the two surfaces of the curved portion of the outer waveguide plate are 0.8 mm and 1.2 mm respectively, while the arc radii of the two surfaces of the curved portion of the inner waveguide plate are 0.2 mm and 1.2 mm respectively. 0.6mm.

According to a preferred embodiment of the present invention, the distance between the outer waveguide plate and the inner waveguide plate is 0.1-0.5 mm, and the medium between the plates and in the groove is air.

Compared with the prior art, according to the technical solution of the present invention, not only the bending loss of the terahertz wave is reduced, but also the structure is simple, the use is convenient, and the cost is low.

Description of drawings

Figure 1 schematically shows the structure of a terahertz low-loss curved waveguide according to a preferred embodiment of the present invention in a perspective view;

Fig. 2 further schematically shows the structure of a terahertz low-loss curved waveguide according to a preferred embodiment of the present invention in a side view.

Detailed ways

The terahertz low-loss curved waveguide of the present invention will be described in detail below with reference to the accompanying drawings. Those skilled in the art should understand that the embodiments described below are only illustrative illustrations of the present invention, and are not intended to limit it in any way.

As shown in Figure 1, in a preferred embodiment according to the present invention, the terahertz low-loss curved waveguide includes two metal plates, namely the outer waveguide plate 1 and the inner waveguide plate 2, both of which are curved metal plates , the bending part (corner) is arc-shaped, the outer waveguide plate 1 and the inner waveguide plate 2 are placed in parallel and there is a certain gap between the outer waveguide plate 1 and the inner waveguide plate 2, and the outer waveguide plate 1 and the inner waveguide plate 2 Periodic grooves are provided on opposite surfaces of the outer waveguide plate 1 , that is, periodic grooves 11 are provided on the inner surface of the outer waveguide plate 1 and periodic grooves 21 are provided on the outer surface of the inner waveguide plate 2 . In addition, it can be understood that the number of grooves can be determined according to the actual required transmission length, where the transmission length refers to the transmission length of the terahertz signal in practical applications, that is, the length of the waveguide.

The outer waveguide plate 1 and the inner waveguide plate 2 may have similar shapes, and the grooves 11 on the outer waveguide plate 1 and the grooves 21 on the inner waveguide plate 2 may have the same size and interval. Preferably, the grooves 11 and 21 are symmetrically distributed with respect to the center line between the outer waveguide plate 1 and the inner waveguide plate 2 .

The terahertz wave is input from one end of the outer waveguide plate 1 and the inner waveguide plate 2 in the transverse magnetic wave mode, enters the gap between the outer waveguide plate 1 and the inner waveguide plate 2, forms a surface wave, and is transmitted in the gap, and then transmitted to the outer waveguide plate 1 and the other end of the inner waveguide plate 2, so as to realize low bending loss transmission of terahertz waves.

It should be pointed out that the bending angle of the bent metal plate (that is, the outer waveguide plate 1 and the inner waveguide plate 2 ) can be any angle, for example, 90°.

The bending radius of the waveguide is preferably greater than 500 μm. Here, the bending radius of the waveguide refers to the bending radius of the center line between the outer waveguide plate 1 and the inner waveguide plate 2 at the bending portion.

This terahertz curved waveguide can change the transmission direction of terahertz waves with low loss. In addition, those skilled in the art can understand that the transmission of terahertz waves in different wavebands can be realized by adjusting the groove size and the plate spacing between the outer waveguide plate 1 and the inner waveguide plate 2 .

Next, the structure of the terahertz low-loss curved waveguide according to a preferred embodiment of the present invention will be further described with reference to FIG. 2 . As shown in Figure 2, the distance D between the outer waveguide plate 1 and the inner waveguide plate 2 is 200 μm, the depth H of the grooves 11 and 21 is 274 μm, the width W of the grooves 11 and 21 is 152 μm, and the grooves 11 and 21 appear The period T is 475μm, the plate length L1 is 3mm, the plate length L2 is 3mm, the plate thickness S is 0.4mm, the plate width is 2mm, the arc radius R1 is 0.2mm, the arc radius R2 is 0.6mm, and the arc radius R3 is 0.8mm, arc radius R4 is 1.2mm, the bending radius of the waveguide is 700μm, the length of the groove is the same as the width of the waveguide plate, the bending angle of the outer waveguide plate 1 and the inner waveguide plate 2 is 90°, between the plates and in the groove The medium is air.

Next, exemplary main processing steps (steps 1-2 below) and loss testing (steps 3-4 below) of the terahertz low-loss curved waveguide according to a preferred embodiment of the present invention are described together.

1) First process two metal plates with a certain thickness and 90° bending (outer waveguide plate 1 and inner waveguide plate 2) according to the size by mechanical processing, and then process on the corresponding surface of the metal plate by mechanical micromachining Out the grooves 11, 21, as shown in Figure 2.

2) Place the grooved surfaces of the outer waveguide plate 1 and the inner waveguide plate 2 in parallel, and further make the grooves 11 and 21 correspond to each other, while ensuring that the two plates are relatively parallel.

3) Turn on the time-domain terahertz spectroscopy system (TDS system), and connect the terahertz low-loss curved waveguide made above as shown in Figure 2 to a suitable position in the TDS system, so that the terahertz signal is transmitted from the terahertz low-loss Slit incidence on one end of the curved waveguide.

4) Collect data: Use the photoconductive receiver of the TDS system to collect the output signal of the terahertz low-loss curved waveguide.

Test results show that the signal transmittance of the output signal of the terahertz low-loss curved waveguide at 0.4 THz to 0.6 THz is higher than 95%, which is obviously better than the loss of the curved waveguide in the prior art.

The terahertz low-loss curved waveguide of the invention has the advantages of simple structure, convenient use and low cost.

Claims (10)

1. a Terahertz low-loss curved waveguide, it is characterized in that: comprise outside waveguide plate and inboard waveguide plate, described outside waveguide plate and described inboard waveguide plate are crooked metallic plate and bend is circular-arc, described outside waveguide plate and described inboard waveguide plate are arranged in parallel each other apart, are respectively equipped with periodically groove on the surfaces opposite to each other of described outside waveguide plate and described inboard waveguide plate.

2. Terahertz low-loss curved waveguide according to claim 1, the metal material of wherein said outside waveguide plate and described inboard waveguide plate is a kind of in aluminium, copper, silver, iron, nickel.

3. Terahertz low-loss curved waveguide according to claim 1, the angle of bend of wherein said waveguide is right angle, bending radius is greater than 500 μ m.

4. Terahertz low-loss curved waveguide according to claim 1, wherein said outside waveguide plate and described inboard waveguide plate shape are similar, and size and the gap periods of the groove on the groove on the waveguide plate of the described outside and described inboard waveguide plate are all identical.

5. Terahertz low-loss curved waveguide according to claim 1, the groove on the groove on the waveguide plate of the wherein said outside and described inboard waveguide plate is about the center line symmetry between described outside waveguide plate and described inboard waveguide plate.

6. Terahertz low-loss curved waveguide according to claim 1, the width of wherein said groove is 50～500 μ m, and the degree of depth is 50～500 μ m, and length is for being not less than 500 μ m.

7. Terahertz low-loss curved waveguide according to claim 6, the width of wherein said groove is 152 μ m, the degree of depth is 274 μ m.

8. Terahertz low-loss curved waveguide according to claim 1, the periodic intervals of wherein said groove is 475 μ m.

9. Terahertz low-loss curved waveguide according to claim 1, the arc radius on two surfaces of bend of wherein said outside waveguide plate is respectively 0.8mm and 1.2mm, and the arc radius on two surfaces of bend of described inboard waveguide plate is respectively 0.2mm and 0.6mm.

10. according to the described Terahertz low-loss of any one curved waveguide in claim 1-9, the spacing between wherein said outside waveguide plate and described inboard waveguide plate is 0.1～0.5mm, and reaching medium in described groove between plate is air.

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