Ultrasensitive Multiple Guided-Mode Biosensor With Few-Layer Black Phosphorus

With few-layer black phosphorus (BP)-based one-dimensional photonic crystal (1DPC), a novel optical biosensor based on the guided-mode resonance (GMR) is proposed for enhancing the sensitivity. Due to the strong coupling of the GMR with itself, the resonance dip of GMR signal will split into more resonance dips with the addition of basic constituent unit. The resonance dips are found to be deeper and deeper to enhance the resonance with the addition of period of 1DPC. Of particular interest is that the enhanced GMR signal can produce a contribution to improve the sensitivity of the biosensor. Therefore, the ultrasensitive GMR biosensor with few-layer BP-based 1DPC is designed to get a high sensitivity (S-max = 20683 RIU-1). For a comparison to the conventional surface plasmon resonance (SPR) sensor (S-max = 59 RIU-1), the sensitivity of the proposed GMR sensor has been enhanced 350 times. The BP-based 1DPC configuration, which could be developed as a promising replacement of metallic thin film, has enriched the application of GMR phenomenon in the biosensing technologies.