A microfluidic terahertz photonic crystal fiber based on an equidistant layered structure

Abstract

The present invention discloses a microfluidic terahertz photonic crystal fiber based on an equidistant layered structure, the basic structure of which consists of a fiber core, a cladding, two left and right water inlets, and a microfluidic channel. The cladding is an equidistant layered structure, which consists of alternating photosensitive resin and air layers centered on the fiber core. The microfluidic channel is an annular channel connected to the inlet and outlet water in the first air layer of the photonic crystal fiber cladding. The present invention can realize non-contact measurement to monitor the refractive index change of the flowing liquid, and therefore has great development potential in biological and chemical detection and sensing applications.

Description

Technical Field

[0001] The invention relates to the technical field of optical fiber sensing, measurement and terahertz detection, and in particular to a microfluidic photonic crystal optical fiber based on a terahertz equidistant microstructure. Technical Background

[0002] The development of photonic crystal fiber has been around for some time. As early as 1996, JCKnight and others made the first all-internal emission photonic crystal fiber, which was drawn by the stacking method. In addition, these people drew a honeycomb cladding bandgap hollow-core photonic crystal fiber in 1998. In 1999, Cregan designed and made the first hollow-core photonic crystal fiber with photonic bandgap effect. This has attracted widespread attention from all walks of life, and photonic crystal fibers of various structures have been manufactured and applied to different fields. Researchers of photonic crystal fibers will conduct more in-depth explorations in seeking new materials, new structures and realizing new functions.

[0003] Since terahertz technology is recognized as one of the major emerging scientific and technological fields in the 21st century, researchers have applied photonic crystal fibers to the terahertz band since the 21st century, which has led to further development of photonic crystal fibers. In 2002, H. Han et al. broke through the tradition of using quartz as a molding material and made photonic crystal fibers with polyethylene as the base material. This fiber reduced the loss and achieved low-loss and low-dispersion transmission of terahertz waves. In 2014, Wang Jingli et al. designed a terahertz photonic crystal fiber based on rhombus air holes, which achieved single-polarization single-mode transmission within a certain range. In 2016, Rabiul Hasan M et al. proposed a gyroscopic terahertz photonic crystal fiber, which can not only obtain extremely high birefringence, but also reduce loss. At present, for terahertz photonic crystal fibers, researchers mainly introduce air holes of different sizes and shapes to achieve some special functions of photonic crystal fibers.

[0004] Terahertz photonic crystal fiber combines the characteristics of terahertz and photonic crystal fiber. Terahertz technology has high resolution, strong penetration, good security and fingerprint spectral characteristics. The photonic bandgap characteristics of photonic crystal fiber can easily control the propagation of electromagnetic waves. When the size of the photonic crystal is comparable to that of the terahertz wave, the terahertz band can be called for in the terahertz photonic crystal fiber. This makes terahertz photonic crystal fiber have great application potential in communications, security detection, and biological and chemical detection. Summary of the invention

[0005] The present invention aims to provide a non-contact measurement technology to detect the refractive index change of flowing liquid, and specifically provides a terahertz photonic crystal fiber based on an equidistant layered structure.

[0006] The terahertz photonic crystal fiber based on the equidistant layered structure is composed of a cladding, a core, two water inlets and a microfluidic channel. One of them is a water outlet and the other is a water inlet, and the water inlet and outlet are two symmetrical structures. The core is a circular air hole located in the center. The microfluidic channel supports a resonant defect state and can optimize the spectrum response of the terahertz photonic crystal fiber.

[0007] The cladding has an equidistant layered structure, which is composed of a photosensitive resin layer and an air layer arranged alternately around the core, that is, a layer of photosensitive resin and a layer of air are arranged alternately around the circular core at the center. The thickness of each photosensitive resin layer and each air layer is the same.

[0008] The water inlet and outlet penetrate into the upper part of the cladding, the bottom of the water inlet is connected with the first air layer, and is distributed on the left and right sides of the upper part of the cladding, and is very close to the end faces of both ends of the photonic crystal optical fiber.

[0009] The microfluidic channel is located in the first air layer of the cladding and is connected to the water inlet and outlet. In order to fill the first air layer with liquid, an annular wall is added on the left and right sides at a certain distance from the end faces of the optical fiber to seal the first air layer. This sealed air layer is the microfluidic channel.

[0010] The molding material is photosensitive resin.

[0011] The present invention has the following advantages:

[0012] 1. A circular cladding structure is adopted with central symmetry, so that the characteristics of each part are basically the same.

[0013] 2. The symmetrical water inlet and outlet design located in the upper part of the photonic crystal fiber can reduce the loss of the lower part of the photonic crystal fiber and facilitate the liquid to fill the entire channel.

[0014] 3. It is easy to use 3D printing technology to prepare the terahertz photonic crystal fiber used in the present invention.

[0015] 4. The present invention can monitor the refractive index change of flowing liquid by non-contact measurement, and therefore has great development prospects in biological and chemical detection and sensing applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is an overall schematic diagram of a microfluidic terahertz photonic crystal fiber based on an equidistant layered structure.

[0017] Figure 2 This is a schematic diagram of the cross section of a microfluidic terahertz photonic crystal fiber.

[0018] Figure 3 It is a schematic diagram of the water inlet and outlet of the microfluidic terahertz photonic crystal fiber and the microfluidic channel.

[0019] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0020] 1-water outlet; 2-first air layer (annular wall of microfluidic channel); 3-photosensitive resin layer; 4-air layer; 5-fiber core; 6-water outlet; 7-microfluidic channel. DETAILED DESCRIPTION

[0021] The present invention is described in detail below with reference to the accompanying drawings.

[0022] The microfluidic terahertz photonic crystal fiber based on an equidistant layered structure consists of a cladding, a core, a water inlet and outlet, and a microfluidic channel.

[0023] The circular core at the center has a diameter of 3 mm.

[0024] The total length of the photonic crystal fiber is 62 mm.

[0025] The cladding has an equidistant layered structure, consisting of a circular photosensitive resin layer and an air layer arranged alternately with the core at the center, that is, a layer of photosensitive resin and a layer of air are arranged alternately around the circular core at the center. The thickness of each photosensitive resin layer and each air layer is 0.8mm. The cladding has a total of 11 layers, 6 layers of photosensitive resin and 5 layers of air.

[0026] The bottom of the water inlet and outlet is connected to the first air layer and penetrates into the upper part of the cladding. It has a height of 13mm, an inner diameter of 3mm, and an outer diameter of 4mm. It is symmetrically distributed on the left and right sides of the upper part of the cladding, and the distance from the end faces of the photonic crystal fiber is 2mm.

[0027] The microfluidic channel is connected to the water inlet and outlet, and is in the first air layer of the cladding. In order to place the liquid in the first air layer, a 0.1mm thick annular wall is added on both sides 1.9mm away from the end faces of the optical fiber to seal the first air layer. This sealed air layer is the microfluidic channel.

[0028] The present invention is prepared by using a 3D printer, adopting a light-curing molding technology, and using a molding material of a photosensitive resin, the refractive index of which is 1.679 at 140 GHz.

Claims

1. A microfluidic terahertz photonic crystal fiber based on an equidistant layered structure, which consists of a core, a cladding, two water inlets on the left and right, and a microfluidic channel, wherein one of the two water inlets is a water inlet and the other is a water outlet, and the water outlet and the water inlet penetrate into the upper half of the cladding; wherein, The fiber core is a circular air hole located at the center of the cladding, and the cladding is an equidistant layered structure, which is composed of photosensitive resin layers and air layers arranged alternately with the fiber core as the center. The microfluidic channel is an annular channel connected to the water outlet and the water inlet in the first air layer of the photonic crystal fiber cladding, wherein the water outlet and the water inlet are symmetrically located in the upper half of the photonic crystal fiber, and an annular wall is added at a certain distance from the left and right end faces of the optical fiber to seal the first air layer.

2. The microfluidic terahertz photonic crystal fiber based on an equidistant layered structure according to claim 1, characterized in that: The optical fiber core is located at the center of the optical fiber cross section and is surrounded by the cladding.

3. The microfluidic terahertz photonic crystal fiber based on an equidistant layered structure according to claim 1, characterized in that: The optical fiber cladding is an equidistant layered structure, and the thickness of the photosensitive resin layer and the air layer are the same.

4. The microfluidic terahertz photonic crystal fiber based on an equidistant layered structure according to claim 1, characterized in that: The water outlet and the water inlet are symmetrically distributed on the left and right sides of the upper half of the cladding, and have a certain distance from the end faces at both ends of the photonic crystal optical fiber.

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