Low-pass features of optical nano-filters constituted by simple layered structures

Low-pass filtering in the nanoscale is a significant procedure that has recently attracted considerable attention due to the upsurge of state-of-the-art nanophotonic applications. In this work, two consecutive dielectric layers with specific permittivity combination and certain size ratio are found to exhibit good performance as a low-pass filter in the visible and at the nano-frequencies. Despite its simplicity, the device retains a satisfying stability in terms of total transmission at the low frequencies; simultaneously, it is impenetrable for signals containing higher frequencies and is characterized by a lack of electromagnetic resonances. Several graphs verify these beneficial features of the structure and further conclusions related to its operation and functionality are obtained.