A terahertz microfluidic square photonic crystal fiber

Abstract

The present invention provides a terahertz microfluidic square photonic crystal fiber, which consists of a core air hole, a water outlet, a water inlet, four photosensitive resin layers, a first air gap layer and two other air gap layers. The photonic crystal fiber core, the photosensitive resin layer and the air gap layer are all square structures. The core is slightly larger than the other air gap layers. The photosensitive resin layer and the air gap layer centered on the core and radiating outward from the core are of the same thickness. The water outlet is located on the upper side of the optical fiber, and the direction is upward. The water inlet is located on the opposite side of the water outlet, and the direction is downward, and then the direction is turned upward. The material used in the present invention is a photosensitive resin, and the refractive index of this material is 1.679 at 140GHz. Applying photonic crystal fiber to the terahertz band can combine the advantages of both, improve the transmission performance of photonic crystal fiber devices, and has broad development prospects in biology, chemistry, medicine and other aspects.

Description

Technical Field

[0001] The invention relates to the field of optical fiber sensing and measurement, and in particular to a terahertz microfluidic square photonic crystal optical fiber. Technical Background

[0002] Photonic crystal fiber is also called microstructure fiber or holey fiber. Its essence is photonic crystal fiber with defects. In 1992, P. Russell et al. first proposed the concept of photonic crystal fiber based on the light transmission theory of photonic crystal. In 1996, JC Knight drew the first photonic crystal fiber, which is a refractive index guided photonic crystal fiber. In 1998, JCKnight proposed the theory of bandgap photonic crystal fiber. The application scope of photonic crystal fiber is becoming more and more extensive, and researchers are also deepening their research on photonic crystal fiber, mainly including the improvement of fiber materials, the innovation of fiber structure and the expansion of the scope of use.

[0003] With the continuous development of terahertz technology, terahertz has been gradually applied to various fields due to its unique superior electromagnetic properties such as penetration, safety, and spectral resolution. At present, terahertz has made significant progress in biological detection, mobile broadband communication, national security, etc. For example, terahertz technology can be applied to clinical human liver cancer tissue detection, craniocerebral trauma imaging feature extraction and identification, clinical bacterial detection, etc. In addition, the transmission speed of terahertz communication can reach more than 10GB / s. Compared with visible light and infrared rays, terahertz waves have extremely high directionality and strong cloud and fog penetration capabilities. They can carry out directional, highly confidential, and even clear code military communications on the battlefield, and can accurately and efficiently check for dangerous objects such as explosives, weapons, and drugs, thereby avoiding terrorist attacks. Therefore, terahertz technology can also be widely used in maintaining national security.

[0004] The rapid development of photonic crystal fiber and terahertz technology has caused researchers in the field of photonic crystal fiber to gradually shift their focus to the terahertz band. The application of photonic crystal fiber in the terahertz band can combine the advantages of both and improve the transmission performance of photonic crystal fiber devices. It has a very broad development prospect in the fields of biology, chemistry and medicine that have high-precision requirements for sensing and measurement. Summary of the invention

[0005] The present invention adopts 3D printing technology to prepare a microfluidic square photonic crystal fiber with an equidistant layered structure. The 3D printing technology is adopted, because the equipment mainly uses a rectangular coordinate system, and the mechanical parts move along three orthogonal directions, so compared with the common photonic crystal fiber with a circular cross-section, the quality of the prepared square photonic crystal fiber can be greatly improved. In addition, by adding a water outlet and a water inlet to the optical fiber, the cladding can have different refractive indices by placing different liquid analytes in the first air gap, and the structure is simple and easy to operate.

[0006] The technical solution adopted by the present invention is as follows:

[0007] It mainly includes square photonic crystal fiber, water outlet and water inlet. From the cross section, the core of the optical fiber is a square air hole located in the center, the cladding diffuses outward from the square air hole in the core at equal intervals, and the photosensitive resin layer and the air gap layer are cross-distributed in sequence. There is a water outlet on the upper side of the optical fiber, and a water inlet is added on the opposite side.

[0008] The core air hole is an inner layer air hole, which is slightly larger than other air gap layers and is mainly used to pass terahertz waves.

[0009] The cladding is a multi-layer air gap layer and a photosensitive resin layer that are cross-distributed in sequence, and except for the inner air hole, each other air gap layer has the same size as its adjacent photosensitive resin layer. The first air gap layer from the central square air hole to the outside is sealed, and the liquid analyte is placed in the first air gap layer to prevent the injected liquid from leaking.

[0010] The water inlet and outlet are both conduits connected to the first air gap layer. The water outlet is directed upward, and the water inlet is located on the opposite side of the water outlet. The first air gap layer is completely and slowly filled with the injected analyte starting from an air hole. In order to allow the liquid to fill the entire air gap, the present invention turns the downward water inlet to an upward direction, so that the liquid analyte injected from the water inlet can more fully occupy the entire gap space.

[0011] The consumables used in 3D printing technology can be selected from various photosensitive resins suitable for the corresponding printer.

[0012] Compared with the prior art, the technical features and effects of the present invention are as follows:

[0013] The advantage of the present invention is that, by using 3D printing technology, various optical fiber devices with more complex core structures can be manufactured. The common circular waveguide structure is broken, and a square structure is adopted, so that the quality of 3D printed devices is greatly improved. The first air gap layer on both sides of the sealed optical fiber can be filled with various liquid analytes in the first air gap layer, so that the cladding has different refractive indices, which is simple to operate and easy to use. The water inlet and outlet are directly connected to the first air gap layer, and the water outlet is connected to the upper side of the first air gap layer, and the water inlet is connected to the lower side of the first air gap layer. Fluid mechanics can be used to control the flow direction of the injected liquid analyte, and the liquid analyte can more fully occupy the entire gap space. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of an example of a microfluidic square photonic crystal fiber based on a terahertz equidistant layered structure. The device consists of a core air hole 3, a first air gap layer 2, other air gap layers 5, a water outlet 1 and a water inlet 4.

[0015] Figure 2 6 is a schematic cross-sectional view of the optical fiber device along the axial direction.

[0016] Figure 3 This is a schematic cross-sectional view of the water inlet of the optical fiber device. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0018] Based on the microfluidic square photonic crystal fiber with terahertz equidistant layered structure, the device consists of a core air hole 3, a first air gap layer 2, other air gap layers 5, a water outlet 1 and a water inlet 4.

[0019] The cross section of the photonic crystal fiber is a square with a side length of 20mm, including three cross-arranged air gap layers and four photosensitive resin layers, as well as a core air hole in the center. The cross section is a square structure. The side length of the core air hole is 6mm, and the square sizes outward are 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, and 20mm, that is, the photosensitive resin layer and air gap layer centered on the core and radiating outward from the core are both 1mm thick.

[0020] For the first air gap layer, the sealing position is 2 mm away from the end faces of both ends of the optical fiber, and the sealing thickness is 1 mm.

[0021] As for the water inlet and outlet, the distance between the water inlet and outlet and the end faces of both ends of the optical fiber is 2mm, and its outer diameter is 4mm and the inner diameter is 3mm. The water inlet is composed of three parts. The first part is a conduit extending downward from the lower side of the first air gap layer, which is 14mm long. The second part is a conduit extending outward along the horizontal direction, which is 20mm long. The third part is a conduit extending vertically upward, which is 35mm long. The three parts are connected in sequence to form the water inlet. The water outlet is a conduit extending upward from the upper side of the first air gap layer, which is 14mm long, that is, the water outlet is 10mm higher than the optical fiber structure.

[0022] When injecting liquid analyte, such as Figure 1 As shown, the liquid enters the first air gap layer from the water inlet, and after fully filling the entire gap space, it flows out from the water outlet.

[0023] The present invention adopts the photocuring method in 3D printing technology, and uses a photosensitive resin as the material, which has a refractive index of 1.679 at 140GHz. The optical fiber adopts a square structure, which greatly improves the quality of 3D printed devices.

Claims

1. A terahertz microfluidic square photonic crystal fiber, characterized in that: It consists of a core air hole, a cladding, a water outlet and a water inlet. The core of the optical fiber is a square air hole located in the center. The cladding is a multi-layer air gap layer and a photosensitive resin layer that are sequentially cross-distributed. The cladding diffuses outward from the core square air hole at equidistant intervals. The first air gap layer is the first air gap layer of the cladding from the central square air hole to the outside. The water inlet is located below the optical fiber, and the water outlet is located above the optical fiber. The water outlet and the water inlet are both conduits connected to the first air gap layer and the water outlet is directed upward. The water inlet is located on the opposite side of the water outlet and is directed upward. The first air gap layer is sealed at both ends for injecting liquid analytes. The first air gap layer is equidistant from other air gap layers and other adjacent air gap layers.

2. A terahertz microfluidic square photonic crystal fiber as claimed in claim 1, characterized in that: The optical fiber adopts a square structure, each air gap layer of the optical fiber is a square structure, and the air gap layers are equally spaced.

3. A terahertz microfluidic square photonic crystal fiber as claimed in claim 1, characterized in that: The first air gap layer is sealed. For the first air gap layer, the sealing position is close to the end faces of both ends of the optical fiber. Different liquid analytes can be injected into the first air gap layer.

4. The terahertz microfluidic square photonic crystal fiber according to claim 1, characterized in that: The water inlet is located on the opposite side of the water outlet, and the water inlet which is in a downward direction is turned to an upward direction.

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