Detection of the Blood Hemoglobin Using an Electro-optical Biosensor Based on a Structurally Chiral Medium

Abstract

In this work, a biosensor based on a structurally chiral medium (SCM) under the effect of a low-frequency electric field has been designed to detect blood hemoglobin. The introduced structure is irradiated with a circularly polarized light under an electro-optical Pockels effect. A photonic band gap is observed in the transmission spectrum of the right-handed circularly polarized waves, which indicates the circular Bragg phenomenon. The sensor consists of a sample layer sandwiched between two identical SCMs. Sensor performance is evaluated using the transfer matrix method (TMM). The results show that the defect mode is sensitive to any change in the refractive index of the defect layer where the defect layer is infiltrated with samples with different concentrations of blood hemoglobin. Also, it is shown that applying a low-frequency electric field increases the sensitivity of the mentioned sensor. It is observed that the sensitivity can be expanded up to 142.66 nm/RIU by changing the various parameters of the SCM.