Narrowband transparent absorbers based on ellipsoidal nanoparticles.

In this paper, we propose the design of an optical device that is able to selectively absorb impinging light in a desired frequency range while being almost completely transparent outside this range. The proposed absorber is a variant of the optical Salisbury screen we recently proposed [Opt. Lett.41, 3383 (2016)OPLEDP0146-959210.1364/OL.41.003383] but, differently from this earlier version, is transparent for any electromagnetic wave whose frequency is outside the absorption spectrum. Such an absorber also exhibits excellent performance in terms of angular bandwidth and may find application in all scenarios where narrowband absorption is required, such as for light filters or digital sensors. Full-wave simulations confirming the effectiveness of the proposed absorber as well as its robustness toward geometrical defects are provided.