What do the bright and dark spots indicate? Does a bright spot indicate a field enhancement and thus a plasmonic resonance? What is the proper simulation setup to use in Lumerical Software to reproduce experimental results?
I did collaborate on work with a Phd student on modeling by home made ADE-FDTD of plasmon mode on Long Range Dielectric Loaded Surface Plasmon Polariton waveguide by means of home made SNOM device. Unfortunatly few things were published internationaly and in english on this work. However, if you ready for french, i provide the link to his PhD: