| Terahertz waves are located between microwaves and infrared waves,and have excellent characteristics such as instantaneity,low photon energy,and high penetration.They can be used in high-sensitivity detection,high-precision imaging,and wireless communications.At the same time,because terahertz electromagnetic waves will not cause negative ionization hazards to biological tissues and many biomolecules have strong collective oscillations in the terahertz band,which can enhance the sensitivity of biomolecule detection,so with the development of terahertz spectr?m technology,too The research of Hertz wave in biosensing is called an important direction.Metamaterial is an artificial composite electromagnetic material with special physical properties.It has special electromagnetic properties that materials in nature do not have,such as negative conductivity,negative permittivity,optical stealth,etc.Common metamaterials are arranged and composed by designing specific sub-wavelength metal unit structures.Metamaterials can effectively control their electromagnetic properties by changing the metal structure in the periodic structure.Based on the above-mentioned terahertz wave and the structural characteristics of metamaterials,this article mainly carried out research on terahertz biosensors based on metamaterials to achieve high sensitivity and high Q-value sensing characteristics.The main research contents of this paper are as follows:1.A terahertz metamaterial biosensor based on a centrally symmetric split ring structure is proposed.The sensor achieves perfect absorption at 2.5THz,and its Q value is 20.The resonance mechanism and sensing mechanism of the sensor at the resonance point are explored.When a biological test object with a thickness of 5?m is set on the surface of the sensor,the sensitivity of the sensor reaches 750GHz/RIU.At the same time,the response of the sensor to the thickness change of the object to be measured is analyzed,and its sensitivity reaches 60GHz/?m.By designing a semi-spherical structure to simulate cell proliferation and cell mutation in biosensing,and applying it to the sensor's sensor performance simulation test,a higher sensitivity is obtained.2.Due to the fact that unimodal sensing is susceptible to interference in practical applications,the accuracy of the sensor is reduced,and a terahertz metamaterial biosensor based on a centrosymmetric F-shaped structure is proposed.The sensor obtains perfect absorption peaks at 3.5THz and 5.95THz,and its Q values ??are 30.8 and 49.6,respectively.The resonance mechanism and sensing performance of the two absorption peaks of the sensor are analyzed.When the thickness of the test object is 5?m,the sensitivities in the two modes are 900GHz/RIU and 1.8THz/RIU,respectively.The sensitivity to changes in the thickness of the object to be measured on the surface can reach 53 GHz/?m and 108 GHz/?m,respectively.3.Biological agents and biological cells are usually detected in solution.Microfluidic technology is increasingly used in the field of biosensing due to its excellent performance in effective control of trace liquids.This section proposes a microfluidic metamaterial sensor based on a spindle structure,which achieves a perfect absorption peak at 3.1 THz and a Q value of 20.7.The electric field of the sensor is mainly distributed in the microfluidic channel,which enhances the interaction between the liquid analyte in the channel and the electromagnetic field,thereby improving the sensitivity of the sensor.Finally,the sensing characteristics of the sensor are analyzed.When the refractive index of the liquid analyte in the microfluidic channel changes,its sensitivity reaches 1200 GHz/RIU.The sensor is not sensitive to changes in incident angle.4.Considering the weak anti-interference ability of single-mode sensing,a dual-mode microfluidic metamaterial sensor based on dual SRR ring structure is proposed,which achieves two perfect absorption peaks at 1.98 THz and 2.56 THz.The Q values ??are 16.5 and 17.1,respectively.The resonance frequency of the two absorption peaks of the sensor can be controlled by changing the length of the inner and outer rings.The sensitivities at the two resonance points are 625GHz/RIU and 900GHz/RIU,respectively.Achieved dual-mode sensing with high sensitivity and high Q in the terahertz band... |
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