A theoretical approach for a new design of an ultrasensitive angular plasmonic chemical sensor using black phosphorus and aluminum oxide architecture

Abstract

A systematic view of the proposed hybrid SPR sensor.

High-performance biosensors based on angular plasmonic of a multilayer design: new materials for enhancing sensitivity of one-dimensional designs

“…3 that the presence of an additional dielectric layer in structure-2 enhances the transformation of the incident light, corresponding to TM polarization at the resonance angle into surface plasmons due to the energy reduction associated with resonance dip. 6 This enhancement of surface plasmons can be visualized by observing the decrease in the energy, which is associated with resonance dips, corresponding to the samples of refractive indices 1.33 and 1.34 positioned at resonance angles 77.37° and 79.44°, respectively in the reflectance spectra, as shown in Fig. 3 .…”

“…Thus, a little portion of the incident electromagnetic waves is confined through Ag's layer as an evanescent wave. 6 Then, the excitation of SPR is introduced due to coupling between the confined evanescent wave and the surface plasmon resonance as a result of the matching between the wave vector of the incident electromagnetic wave and that of the surface plasmon. 2–6 Interestingly, the resonant dip appears within the reflectance spectrum due to the excitation of SPR.…”

“…The ratio of resonant angle ( θ R ) with full-width half maximum (FWHM) of the resonant dip is defined as the quality factor of the biosensor. Mathematically it can be defined as follows: 6 …”

“… 5 The incident transverse magnetic (TM) electromagnetic wave (EM) of a specific wavelength through the interface of a metal/dielectric slabs induces the free electrons of metal to oscillate collectively, which, in turn, start propagating along the interface due to the energy transfer, which is carried by the incident EM wave to free the electrons of metal surface. 6 This collective propagation of free electrons along the interface between the metal and dielectric is known as surface plasma waves (SPWs). 7 The coupling between SPWs and the evanescent wave, which results from phase matching, is a requirement for achieving the SPR conditions.…”

“… 7 The coupling between SPWs and the evanescent wave, which results from phase matching, is a requirement for achieving the SPR conditions. 8 The fulfillment of this condition results in the resonant dip in the reflectance response of the structure 6–8 as the excitation of surface waves is not possible directly through a 3D beam. There are different excitation techniques, such as the Kretschmann configuration, in which, a prism is used for the excitation of surface plasmons, Otto configuration, fiber coupling, and greeting coupling schemes, which are used by researchers worldwide.…”