Ultrathin metamaterial-based refractive index sensor for biomedical applications

Abstract

This work presented an ultrathin terahertz metamaterial-based sensor in the terahertz region. The suggested design comprised of gold metasurface atop on layer of dielectric spacer and a layer of gold at the bottom. The simulation results display dual frequencies found at 1.04 THz and 2.655 THz with absorptance rate closed to 100%. The suggested design displays sharp peaks and a maximum Q value of 132.75 in the dual-band absorptance profile. Moreover, the suggested sensor displays polarization independence which will eradicate the polarization demand of the device. The dual peaks of the suggested sensor are extremely sensitive to the refractive index variation of surrounding medium. Furthermore, the suggested sensor sensitivity increases up to 0.76THz/RIU and figure of merit (FOM) reaches up to 38 RIU-1 lies between 1 to 2 RI range at 50 μm analyte thickness selected. Additionally, the sensor device has the ability of detection of glucose and malaria infection with high sensitivity and FOM.

A Flexible Terahertz Metamaterial Sensor for Pesticide Sensing and Detection

“…The THz sensors can be categorized into several types. The first type is the refractive index sensor, which infers the refractive index of the analyte attached to the sensor surface based on the change of the sensor’s resonant frequency. − The second type is the biosensor, capable of detecting DNA short sequences, thrombin, carcinoembryonic antigen (CEA) biomarkers, glucose, − microorganisms, and corneal tissues, ensuring food security, and identifying viruses , and cancer cells, , while some other biosensors have been achieved through on-chip design. , Furthermore, the pesticide sensor is also a hot topic, aiming to detect pesticide concentration through variations in resonant peaks (frequency or amplitude shifts). Some recent works have focused on detecting pesticides like 2,4-dichlorophenoxyacetic acid (2,4-D), chlorpyrifos-methyl, and phosalone. − In addition, other types of THz sensors include temperature metamaterial sensors for low-loss amplitude modulators and temperature-controlled THz devices, − as well as photonic sensors for ultrafast all-optical switching and precise label-free immunosensing. , …”