Investigation Of Liquid Sesnor Based On Terahertz Surface Plasmon

Terahertz wave has the characteristics of wide electromagnetic wave spectrum,strong penetrability,safety,high temporal resolution,phase coherence of electromagnetic field and strong spectral resolution,which makes terahertz wave technology widely used in broadband communication,astronomy and medicine Imaging,non-destructive testing,security inspection and other fields.Especially terahertz wave has low photon energy and non-destructive testing advantages,more suitable for biomedical testing.In this paper,the terahertz surface plasmonic liquid sensor was designed by using the terahertz plasma effect of PVDF(PVDF)and metal-medium-metal waveguides.The designed sensor was applied to liquid sample detection and Better effect.Specific results are as follows:1.A plasma resonant liquid terahertz sensor based on PVDF(polyvinylidene fluoride)was designed.A novel ferroelectric polymer PVDF has been successfully fabricated on the surface of the material using silicon prisms coupled with the ideal dielectric properties in the terahertz band.And then the structure parameters were adjusted and optimized to achieve the best sensitivity of 0.393 THz / RIU.At the same time,in order to prove the structure of the liquid medium can be used to sense the sensor used to identify distilled water and three kinds of human cancer cells,to obtain a more satisfactory results.2.A terahertz surface plasmon vibration sensor based on PVDF three-layer structure is designed.The main structure is a symmetrical three-layer structure composed of two layers of high density polyethylene(HDPE),PVDF film The symmetrical electric field generated when the upper and lower surfaces stimulate the plasma resonance are coupled and enhanced.Firstly,the frequency reflection spectrum is calculated by using the transfer matrix method(TMM),and the electric field distribution of the resonant point is simulated by FDTD method,and the mechanism of coupling enhancement is verified.And then the sensor in the frequency scanning mode and angle scanning mode of work sensitivity,linearity and other performance were analyzed.Finally,the three-layer structure thickness,working angle,operating frequency and other parameters of debugging and optimization to get the best sensitivity and linearity indicators.The simulation results also show that the three-layer structure has the advantage of sensitivity and linearity for single-layer PVDF terahertz plasma sensors..3.A liquid sensor with a helical metal-medium-metal waveguide structure is designed to excite terahertz surface plasmon resonance.By combining a branch structure on a subwavelength metal-dielectric-metal waveguide waveguide,the frequency transmission spectrum of the waveguide produces a significant resonance peak.In the branch structure into the liquid to be measured,the resonant peak with the liquid refractive index changes to move,so as to achieve the measured liquid sensing.The sensor is optimized to achieve the best sensitivity of 0.457 THz / RIU,FOM value of 3.1.This sensor was used to simulate the known water and three kinds of human cancer cells in the dielectric model,and the ideal effect was obtained.