Publication

Abstract : Grating-based optical sensors are promising, especially for refractive index (RI) sensing applications. Nonetheless, achieving higher or improved sensitivity in these sensors for detecting specific biomolecules, such as female reproductive hormones, remains an ongoing challenge. Estrogen is a crucial hormone in the female reproductive system, playing a vital role in regulating menstrual cycles, supporting pregnancy, and maintaining bone density and cardiovascular health. Therefore, this work aims to overcome the limitations by introducing a plasmonic sensor to optimize detection accuracy. The optical sensor structure, known for its immunity to electromagnetic interference and adaptability in various sensing applications, provides an ideal platform for precise RI detection. The sensor design has a unique plus-shaped cavity with layers of gold (Au), iron oxide(II) (FeO), and graphene oxide (GO). Incorporating Au and FeO on the sensor surface improves light-matter interactions and generates surface plasmon. The FeO has been synthesized using the combustion technique and its surface morphology is studied using scanning electron microscopy. The GO layer is introduced to improve the biocompatibility of the sensor. The model is tested within the RI range of 1.3332–1.3359 for the concentration level in the blood sample of 0–1.3 nmol/L of estrogen. Through two-dimensional finite difference time domain simulations, the sensor demonstrates an impressive detection autocorrelation coefficient of 99.27%. This level of precision offers significant potential for applications in medical diagnostics, particularly in monitoring biomolecule levels for reproductive health and endocrinological studies.