A Biomedical Sensor for Detection of Cancer Cells Based on Terahertz Metamaterial Absorber

Abstract

A terahertz metamaterial absorber, capable of detecting cancerous cells, is proposed in this letter. The proposed design consists of several merged circular ring resonators over a gallium arsenide substrate. It achieves an absorption of 99% at 3.71 THz and a high quality factor ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> -factor) of 92.75. The resonance frequency shifts with alterations in the refractive index of the encompassing medium, which is used to detect cancerous cells. The refractive index has varied in the range of 1.3–1.40, and its sensitivity is 1447 GHz/RIU. The equivalent circuit is proposed, and the resonance mechanism is studied. The structure behaves as an epsilon negative metamaterial, and the resonance is plasmonic. The sensor's high <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> factor and a figure of merit of 36.175 have several biomedical sensing applications.