High-performance terahertz biosensor utilizing a hybrid one-dimensional photonic crystal with liquid crystal and graphene components

In recent decades, advances in biophotonics research have led to the development of numerous novel applications, particularly in the realm of diagnostic tools. Among these, one-dimensional photonic crystal biosensors have emerged as frequently utilized instruments for disease diagnosis and sensing. A significant body of research has focused on enhancing the efficiency of these biosensors. Recently, integration of Graphene and liquid crystal into a hybrid structure has been identified as a promising approach for the advancement of optical devices. This study presents a novel one-dimensional photonic crystal biosensor designed using the Kretschmann configuration, which incorporates Graphene nanolayers and a liquid crystal layer. The transfer matrix method was employed to calculate the projected band structure of the designed biosensor for different chemical potentials of the Graphene nanolayers. Additionally, the dispersion properties of the surface waves can be tuned by adjusting the liquid crystal director angle. By manipulating the adjustable parameters of the Graphene nanolayer and liquid crystal, modifications to the reflection spectrum can be achieved, facilitating an analysis of angular sensitivity and figure of merit. The results indicate that these parameters significantly influence sensitivity and figure of merit of the biosensor. Notably, increases in the chemical potential of the Graphene nanolayers, along with adjustments to the liquid crystal director angle, substantially enhance the performance of the biosensor. Our study achieved a maximum sensitivity of $$\:{199.41}^{^\circ\:}/RIU$$ at a graphene chemical potential of $$\:1.2\:eV$$ and a liquid crystal orientation angle of $$\:{90}^{^\circ\:}$$ . Additionally, a maximum figure of merit of $$\:6649\:{RIU}^{-1}$$ was obtained at a chemical potential of $$\:0.8\:eV$$ and an orientation angle of $$\:{90}^{^\circ\:}$$ . The proposed sensor is deemed suitable for practical applications due to its straightforward fabrication process and capability to operate at room temperature. Moreover, the properties of both the Graphene nanolayers and the liquid crystal layer in the biosensor can be readily adjusted, further contributing to its versatility and efficacy.