INVERSE DESIGN OF QUASIMONOCHROMATIC LIGHT SOURCES IN THE VISIBLE RANGE

Emission of thermal light from a hot body was considered during long time as broadband and quasi-isotropic. Today we know that various micro and nanostructured materials1-5 (see also the refs. in [5]) are able to radiate in narrow spectral bands and around specific directions of space. In a recent work6 we have developed a general method for the ab initio design of multilayered coherent thermal sources. This method consists first in setting the coherence degree that we want to recover and then using only the first principles of optics we search, using a genetic algorithm, for the ad hoc structure of a multilayered medium to satisfy this specification. Here, we report the design of quasi-monochromatic 1-D metallodielectric sources for both polarization states in the visible range. The type of structures we investigate in this work are one-dimensional plasmonic stacks built by superposing nanolayers of metals with different dielectric materials. All these composites materials are formed from M unit nanolayers of the same total thickness L. The total number of all possible configurations that can be theoretically fabricated with N distinct materials is MN. For ternary structures made with 50 unit layers there are more than 2310 possible configurations. Such a large space S offers immense possibilities to sculpt the radiative properties of nanolayered composites. To explore effectively this vast space of composite materials and identify the structures whic