• Photonics Research
  • Vol. 12, Issue 11, 2667 (2024)
Liang Guo, Lei Xu, and Liying Liu*
Author Affiliations
  • Key Laboratory for Micro and Nanophotonic Structures (Ministry of Education), Department of Optical Science and Engineering, School of Information Science and Engineering, Fudan University, Shanghai 200433, China
  • show less
    DOI: 10.1364/PRJ.530126 Cite this Article Set citation alerts
    Liang Guo, Lei Xu, Liying Liu, "Sensitivity enhancement of guided mode resonance sensors under oblique incidence," Photonics Res. 12, 2667 (2024) Copy Citation Text show less

    Abstract

    The sensitivity of guided mode resonance (GMR) sensors is significantly enhanced under oblique incidence. Here in this work, we developed a simplified theoretical model to provide analytical solutions and reveal the mechanism of sensitivity enhancement. We found that the sensitivity under oblique incidence consists of two contributions, the grating sensitivity and waveguide sensitivity, while under normal incidence, only waveguide sensitivity exists. When the two contributions are constructively superposed, as in the case of positive first order diffraction of the grating, the total sensitivity is enhanced. On the other hand, when the two parts are destructively superposed, as in the case of negative first order diffraction, the total sensitivity decreases. The findings are further supported by FDTD numerical calculations and proof-of-concept experiments.
    Λ(ncsinθinwsinθd)=jλ,              j=0,±1,.

    View in Article

    k0nwdwcosθdΦw,cΦw,s=mπ,          m=0,1,2,.

    View in Article

    Φw,c=arctan(nw2nc2)ρ(N2nc2nw2N2)12,

    View in Article

    Φw,s=arctan(nw2ns2)ρ(N2ns2nw2N2)12.

    View in Article

    N=nwsinθd.

    View in Article

    N=ncsinθijλ/Λ,    j=±1,.

    View in Article

    F(λ,nc)=2πλnwdwcosθdΦw,cΦw,s.

    View in Article

    S=dλdnc=F(λ,nc)ncF(λ,nc)λ.

    View in Article

    λ=2nwπdw1N2nw2arctan(nw2ns2)ρ(N2ns2nw2N2)12+arctan(nw2nc2)ρ(N2nc2nw2N2)12,

    View in Article

    λ=Λ(ncsinθiN)/j,            j=±1,.

    View in Article