Terahertz Sensor Study Based on Spoof Surface Plasmon Polaritons

Abstract

The spoof surface plasmon polaritons (SSPPs) structure can be used as a sensor in THz region for the biosensing. The accuracy of resonance and amplitude for sensor is very important for biosensing. The momentum matching of SSPPs determines the resonance position and the gap distance determines the amplitude. For the biomolecular sensing, the sample is positioned between the prism base and the SSPPs structure. The momentum matching condition at the current study does not consider the effect of sample refractive index and the resonance position has a significant error. Here the correction is made to the momentum matching condition which considers the effect of the sample refractive index. A comparative study of surface plasmon resonance (SPR) sensing performance based on frequency and angle variations shows that the sensing sensitivity for frequency region is superior to that of angle region; in the meanwhile, as an application of biosensors, we have detected different types of brain lesions in the frequency range. Furthermore, the reflection amplitude is related to gap size between the prism and SSPPs. The relationship of gap size and reflection amplitude is studied. By using the relationship between gap size and reflection amplitude, the amplitudes at different frequencies or incident angles for different refractivities have the same reflection dips compared to the other published results. The simulation is performed and the results proved the theory.

Numerical Optimization of Refractive Index Sensors Based on Diffraction Gratings with High Aspect Ratio in Terahertz Range

“…The estimation according to Equation (6) gives the refractive resolution , which has the same order as in the best optical fiber refractometers in the visible and near infrared ranges [ 29 ], and as in the ultrasensitive dielectric metagratings in the subTHz domain [ 12 ]. Besides, the obtained refraction resolution is much higher than in the most sensitive THz subwavelength metal gratings using Otto prism coupling [ 20 ].…”

“…Another type of the sensor design based on subwavelength gratings and Otto prism coupler was proposed by Ng et al [ 13 ]. Such sensors were developed in the works of other authors [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ], who obtained the maximum sensitivity to be as high as 3.57 THz/RIU. The corresponding figure of merit (FOM) is 3966 [ 20 ].…”

“…Such sensors were developed in the works of other authors [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ], who obtained the maximum sensitivity to be as high as 3.57 THz/RIU. The corresponding figure of merit (FOM) is 3966 [ 20 ]. However, one of the traditional approaches to realize high sensitivity SPR sensors based on metal diffraction gratings has been studied poorly in the terahertz frequency range.…”

Microwave Spoof Surface Plasmon Polariton-Based Sensor for Ultrasensitive Detection of Liquid Analyte Dielectric Constant

“…However, SPPs are not supported at far-infrared, microwave, and terahertz frequencies, and the concept of spoof surface plasmon polaritons (SSPPs) was introduced by using designed structures and plasmonic metamaterials [ 44 , 45 ] with the aim to mimic SPP propagation in those frequency ranges. Different planar designs that support SSPP propagation were proposed in the literature, based on gradient holes [ 46 ], corrugations [ 47 , 48 ], zigzag grooves [ 48 ], grooves with circular patches [ 49 ], and disk resonators [ 50 , 51 ]. In addition, SSPP properties were used for the realization of filters [ 52 , 53 , 54 ], antennas [ 55 , 56 ] and waveguide systems [ 57 , 58 , 59 ].…”

Terahertz Sensor via Ultralow-Loss Dispersion-Flattened Polymer Optical Fiber: Design and Analysis

“…The characteristics of the wide-spectrum, strong-penetration, high-security terahertz (THz) wave have all-important applications in THz tomography [ 1 , 2 ], detection technology [ 3 , 4 ], biomedical sensing [ 5 , 6 , 7 , 8 , 9 ], THz communication [ 10 , 11 ], polarization maintenance [ 12 , 13 , 14 ], nondestructive testing [ 15 ], and other fields. The THz functional device is based on the waveguide structure and is the premise to realize various application functions.…”