Determining and characterizing families of electronic resonance states in open and closed coupled cavities

Here a straightforward procedure to characterize electronic resonances in arbitrary coupled open or closed nano and micro structures – formed by cavities (or billiards) connected by waveguides – is presented. Based on the boundary wall method, it identifies families of states arising from continuous changes in the system geometric parameters without the necessity to explicit calculate the eigenfunctions. Nevertheless, if desired they also can be obtained with good numerical accuracy. As a case study, two rectangular cavities coupled to waveguides is considered. It is exemplified how the bound states, bound states in the continuum and truly transmission states respond to certain modifications in the problem geometry. The analysis simplicity illustrates the potential of the approach in ascertaining structures shapes with distinct resonance properties