Shaping the spontaneous emission of extended incoherent sources into composite radial vector beams

Abstract

It is well known that concentric diffraction gratings are capable of beaming the spontaneous emission of large extended incoherent light sources (e.g. hot radiating surfaces and luminescent materials). Here, we reveal additional properties of such beams using layers of colloidal PbS nanocrystals coated onto metallic spiraling gratings as an example. We observe and explain with a simple model the formation of multiple beams when the spirals are deformed. We also point out an aspect of the light emission that does not seem to have been discussed so farnamely, that the polarization of the directional beams has a radial distribution. These findings are not restricted to our experimental configuration, suggesting a simple way to build incandescent and electroluminescent sources with non-trivial polarization states. The price to pay is an isotropic emission background due to the composite nature of the beams, which result from the incoherent superposition of a continuum of diffracted plasmons everywhere above the surface.

Plasmon‐Assisted Directional Infrared Photoluminescence of HgTe Nanocrystals

“…In the context of infrared sensing, this approach has generated a significant amount of work to enhance [22][23][24][25][26][27] device absorption, reshape the spectral response, [28,29] or enable a bias reconfigurable response. [30,31] However, far less work has been focused on using photonic structures [32,33] to enhance outcoupled PL signal of infrared-emitting NC films, [34][35][36][37][38] and even less for HgTe films in particular. [39,40] Sergeev et al have proposed coupling HgTe NC emitters to a laser-printed bump array [39] and achieved a fivefold enhancement of the PL.…”