Abstract-Biomedical Sensing with Free-Standing Complementary Supercell Terahertz Metasurfaces

Ibraheem Al-Naib

https://www.google.com/url?rct=j&sa=t&url=https://www.mdpi.com/2073-4352/10/5/372/pdf&ct=ga&cd=CAEYACoTMjM2MzIyMDcwNTg1MDM2MDg4MDIaNGU4NDJkNGZkMTkwOWEyODpjb206ZW46VVM&usg=AFQjCNE9guHw9vbsXLE7XGVOm38rlrpLhw

We present a free-standing terahertz metasurface supercell that consists of four complementary mirrored asymmetric split-rectangular resonators. The quality factor of the excited resonance of this supercell has been significantly improved by 250% when compared to its counterpart nonmirrored supercell. The mirroring of the resonators leads to an enhanced out-of-phase oscillating current in each neighboring resonators of the supercell. In turn, this leads to a suppression of the dipole moments and its corresponding scattered fields. Moreover, this design can be realized by utilizing a simple laser machining technique. Furthermore, we numerically evaluate the performance of this design as a label-free biosensor for thin-film analytes and biomolecules such as double-stranded DNA and single-stranded RNA viruses. A sensitivity level of 1.14 × 105 nm/refractive index unit (RIU) can be achieved using this design. Therefore, this design has the potential to be used as an effective label-free biomedical sensor for in-situ detection of various biomolecules

Abstract-Advances in biomedical imaging using THz technology with applications to burn-wound assessment

Priyamvada Tewari, Colin Kealey, Jun Sung, Zachary D. Taylor

https://www.researchgate.net/publication/258712377_Advances_in_biomedical_imaging_using_THz_technology_with_applications_to_burn-wound_assessment

Terahertz (THz) hydration sensing and image has been a topic of increased interest recently due largely to improvements in source and detector technology and the identification of applications where current hydration sensing techniques are insufficient. THz medical imaging is an expanding field of research and tissue hydration plays a key role in the contrast observed in THz tissue reflectance and absorbance maps. This paper outlines the most recent results in burn and corneal imaging where hydration maps were used to assess tissue status. A 3 day study was carried out in rat models where a THz imaging system was used to assess the severity and extent of burn throughout the first day of injury and at the 24, 48, and 72 hour time points. Marked difference in tissue reflectance were observed between the partial and full thickness burns and image features were identified that may be used as diagnostic markers for burn severity. Companion histological analysis performed on tissue excised on Day 3 confirms hypothesized burn severity. The results of these preliminary animal trials suggest that THz imaging may be useful in burn wound assessment where current clinical modalities have resolution and/or sensitivity insufficient for accurate diagnostics

Abstract-Highly Sensitive Terahertz Gas Sensor Based on Surface Plasmon Resonance With Graphene

Yuanjiang Xiang,   Jiaqi Zhu, Leiming Wu,  Qi You,  Banxian Ruan, Xiaoyu Da

One of the most important applications of THz frequencies is biomedical sensing. However, in a THz range, surface plasmon waves on flat metals are not confined and therefore cannot be used for subwavelength sensing. But, it has been shown that graphene can support surface waves at THz frequencies, which has similar properties as plasmonic waves in an optical range. In this paper, a highly sensitive gas sensor in the terahertz frequencies by exciting surface plasmon resonance (SPR) of graphene is proposed. The results show that the proposed SPR gas sensor has high stability and high sensitivity (S), and the highest Smax (∼147°/RIU) has been obtained by optimizing the Fermi energy, the thickness of the dielectric layer, and the incident light frequency. Moreover, the S of the proposed THz sensor for different refractive index (RI) of gas sensing medium (n1) is also discussed.