Surface plasmon based plasmonic sensors: A review on their past, present and future

INTRODUCTION

Two forms of SPs

  • Localized surface plasmons (LSPs)
  • Propagating surface plasmon polaritons (SPPs)
  • Free electrons on the metal surface are excited by evanescent waves to form surface plasmon waves (SPW)
  • SPR will occur when the incident light's wave vector matches that of SPW, resulting in a large EM field on the surface of the metal.

Surface plasmon-based plasmonic sensor structures

Nano array resonator based plasmonic sensors

Rakhshani et al. proposed a plasmonic refractive index sensor.

  • Consist of 2 metal insulator metal (MIM) waveguides couple with a silver nanorod array embedded into a square resonator
  • Used a silver nanorod for unique optical properties of good confinement and low propagation losses

Rakhshani et al. proposed a plasmonic sensor

  • Consist of 2 MIM waveguides coupled with an array of hexagonal nanoholes in a metal substrate (Ag)
  • An analyte was inside the nanoholes, RI of the nanoholes changed => leads to a change in the resonance wavelength of the structure

Ring resonator based plasmonic sensors

Fiber based plasmonic sensors

Defect based plasmonic sensors

Measure refractive index (RI)

Materials

Metals

SPWs are created on the metal-dielectric interface when a monochromatic light source is applied directly to the metal surface

Nanomaterials

  • Graphene
  • Black phosphorous (BP)
  • Transition metal dichalcogenides (TMDCs)
  • MoS2
  • Molybdenum diselenide (MoSe2)
  • Tungsten disulfate (WS2)
  • Tungsten diselenide (WSe2)

Applications

Biosensor
Works based on the refractive index variation due to the binding of biomolecules on the sensor layer

Chemical sensor
Main focus of the applications was on changes in the RI of the sensing layer caused by the adsorption of the analyte molecules

Physical quantities
Based on SPR sensitivity to the momentum of the light wave incident

Future perspective

  1. High sensitivity range
    Detect changes in the local RI caused by biomolecular biding
  1. The miniaturized sensor extends the range of potential applications
  1. Improvement in the analytic figures of merit
  • Nanomaterials are free from corrosion and oxidation
  • 2D nanomaterials can bind to proteins and nucleic acids
  • 2D nanomaterials layer could increase the electrical field at the interface and accelerate the transfer of charges between plasmonic metal and probe molecules due to the high mobility of the carrier => improving the sensitivity of the plasmonic sensor