Designing a light-emitting system means shaping light emission so that it matches requirements in terms of radiation pattern, polarization, or spectrum. Contrarily to lasers, other non-lasing light sources (fluorescent lamps, LEDs…) emit light by spontaneous emission, an intrinsically random process in which each photon is produced with its own phase, polarization, and direction. This behavior is at odd with the precise phase conditions that are required to construct directional and/or polarized beams, resulting in an isotropic, incoherent and unpolarized emission.

Light-Emitting Metasurfaces (LEMs) are an answer to this issue. LEMs contain arrays of nanoresonators, but at the difference of other conventional diffractive metasurfaces, LEM integrate nanoscale sources (molecules quantum dots (QDs), thermal emitters…) within the device. The emitted wavefront can be shaped into an arbitrary complex field via the interaction between incoherent emitters with the LEM surface modes.

In this presentation, we report on the whole process of quantitative design, fabrication and characterization of actual devices providing highly directional photoluminescence, combining a thin layer of photoluminescent nanoplatelets with 1D or 2D metallic gratings. Our samples were designed following a generalized Kirchhoff’s law based approach: the absorption features of the structure are engineered in order for the photoluminescence to display adequate reciprocal features.