Hybrid Semiconductor Plasmonic Lasers for Biochemical Sensing: Theory and Design

An electrically driven InP-based Fabry-Perot biochemical sensing laser is proposed and analyzed. The design incorporates a sensing area on top of the laser to alter its characteristics and operates in a hybrid plasmonic-semiconductor lasing mode. Our device is designed for an etch-free III-V (InP) based stack, where lateral confinement of the hybrid mode is ensured by a thin gold (Au) strip on a thin indium tin oxide (ITO) strip. We optimize the waveguide geometry to produce maximum sensitivity while having compensable loss. Our investigation centers on three laser characteristics that are affected by the sensing fluid and that could serve as measurands: lasing wavelength, threshold current, and power-current slope efficiency. We determine the sensitivity of each measurand, assess the potential noise sources, and the limit of detection (LoD) associated with them. Our calculations indicate that the proposed biosensor can achieve LoDs as low as 105 RIU when employing the threshold current as the measurand.