Resonant interaction between two core modes in a plasmonic biosensor based on a birefringent solid-core microstructured optical fiber

Abstract

By using a finite element method with matched boundary conditions, we analyze an interaction between a central core mode (x- and y- polarizations), which shows as a supermode and a plasmonic mode by involvement of another (lateral) core mode in a biosensor based on a birefringent solid-core microstructured optical fiber. The transmission losses of the lateral core modes are larger than those of the corresponding central core modes for the x- and y- polarization components. A very interesting result is that the maximum value of the amplitude sensitivity for the second (lateral) core (II, x) mode (x- polarization) is at a wavelength close to the resonant wavelength of the first (central) core (I, x) mode. Also, the maximum value of the amplitude sensitivity for the second core (II, y) mode (y- polarization) is at a wavelength that is close to the resonant wavelength of the first core (I, y) mode.