Broadband absorption in the cavity resonators with changed order

This paper presents an analysis of phenomena leading to high and broadband absorption at a structure combined of three elements: one-dimensional dielectric diffraction grating placed between silver grating and a thick silver substrate. Each element of the dielectric grating consists of media of different dielectric constants but of the same geometrical dimensions. A broad spectrum of high absorption in such a structure is achieved as a result of two issues. First, due to the different excitation conditions the cavity resonances are excited at different wavelengths. Second, the changed order of the resonators leads to further broadening of the absorption band.