Tunable and enhanced performance of graphene-assisted plasmonic sensor with photonic spin Hall effect in near infrared: analysis founded on graphene’s chemical potential and components of light polarization

Abstract

In this work, we propose a graphene-assisted plasmonic structure with photonic spin Hall effect (PSHE) for sensing applications in near infrared with an emphasis on tunable and spin control aspects leading to enhanced performance. We comprehensively investigate PSHE in view of variable chemical doping of graphene monolayer in the structure and manipulation of the spin dependent splitting by considering single and cross polarization states. There is observed a considerable variation in spin shift due to increase in chemical potential or Pauli blocking, which fundamentally controls the light absorption by graphene. Our simulation results reveal that the amplified spin dependent shift (SDS) is 1.13 × 104 times higher than the conventional SDS at 0.436 eV of graphene chemical potential. Further, this structure is utilised for sensing application, and it is observed that graphene-assisted plasmonic based structure possesses significantly greater spin dependent sensitivity (5.53 times), figure of merit (8.56 × 105 times), and extremely finer limit of detection (by a factor of 18.10) are achieved compared to the structure without graphene. The results indicate that choosing the proposed graphene-assisted plasmonic structure with variable chemical potential and light polarization components, an extremely enhanced sensing performance can be achieved. The results are consistent with the physical rationale and are particularly important for potential biosensing applications.