Open AccessGreen’s function for a sharpened and metal-coated dielectric probe
Author(s) -
Vineet Khullar,
Gong Gu,
Ali Passian,
T. L. Ferrell
Publication year - 2018
Publication title -
applied optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.668
H-Index - 197
eISSN - 2155-3165
pISSN - 1559-128X
DOI - 10.1364/ao.57.002150
Subject(s) - optics , near field scanning optical microscope , surface plasmon , laplace's equation , materials science , surface plasmon polariton , aperture (computer memory) , dielectric , near field optics , near and far field , plasmon , surface plasmon resonance , boundary value problem , physics , optical microscope , optoelectronics , nanotechnology , scanning electron microscope , quantum mechanics , nanoparticle , acoustics
In apertureless scanning-probe optical microscopy and in the case of more traditional scanned optical probes coated with a metal that is thin near the probe tip (in lieu of an aperture), samples are probed via interaction between the probe and surface. In the nanometer-scale region between the tip and the sample, the field can be approximated by quasi-electrostatic analytics. Hence, the coated probe can be modeled as in the present case as a hyperboloid of revolution without the need for hyperboloidal wave functions in the near zone. The solutions to Laplace's equation and in general Green's function with the application of the boundary conditions, therefore, yield an appropriate approximation and allow a completely analytical solution for the resonance effects upon the probe tip to be obtained. The large field enhancements due to the sharpness of the tip and to surface plasmon fields may thus be analytically examined.