Tunable UV-Emitters through Graphene Plasmonics

Abstract

Control over the spontaneous emission of light through tailored optical environments remains a fundamental paradigm in nanophotonics. The use of highly-confined plasmons in materials such as graphene provides a promising platform to enhance transition rates in the IR-THz by many orders of magnitude. However, such enhancements involve near-field plasmon modes or other kinds of near-field coupling like quenching, and it is challenging to use these highly confined modes to harness light in the far-field due to the difficulty of plasmonic outcoupling. Here, we propose that through the use of radiative cascade chains in multi-level emitters, IR plasmons can be used to enhance far field spectra in the visible and UV range, even at energies greater than 10 eV. Combining Purcell-enhancement engineering, graphene plasmonics, and radiative cascade can result in a new type of UV emitter whose properties can be tuned by electrically doping graphene. Varying the distance between the emitter and the graphene surface can change the strength of the far-field emission lines by two orders of magnitude. We also find that the dependence of the far-field emission on the Fermi energy is poten- to effectively serve as a "switch" for turning on and off certain plasmonic and far-field emissions.

Nonlinear Atom-Plasmon Interactions Enabled by Nanostructured Graphene

“…These resonances exhibit stronger confinement and longer lifetimes than their noble metal counterparts, and are readily tuned in an active manner via electrostatic gating [12]. For these reasons, the interaction of plasmonic near fields from highly doped graphene with proximal QEs has been predicted to enable observable vacuum Rabi splittings [13], large Purcell enhancement factors [14,15], and electrical control of quantum states [16]. Unfortunately, even at high doping levels, plasmon energies ω p in graphene nanostructures appear in the infrared or terahertz regimes, well-below the frequencies associated with long-lived electronic excitations in robust quantum light sources.…”

Perfect ultraviolet absorption in graphene using the magnetic resonance of an all-dielectric nanostructure

“…A lot of photonic nanostructures have been adopted to trap light on monolayer graphene in the spectral range from visible to infrared, such as plasmonic nanoantennas, plasmonic metamateirals, optical waveguides, and photonic crystals [7][8][9][10][11]. Despite of these research achievements, there is few research about the routes to approaching perfect ultraviolet (UV) absorption in monolayer graphene, which has a variety of promising UV applications on photodetectors, light emitters, Raman microscopy, optical sensing and flame monitoring [12][13][14][15]. A previous effort has been focused on achieving high UV absorption in graphene by using a multilayer structure without any nanostructure patterning [16].…”

Multipolar terahertz absorption spectroscopy ignited by graphene plasmons

“…In general, multipolar absorption is inherently small because it ensues from the electromagnetic field spatial variation within the molecule 19 . However, over recent years it has been shown that such "forbidden" transitions can be accessed by the deepsubwavelength scattered field produced by graphene nanostructures [47][48][49][50][51][52][53][54][55] . Note in Figs.…”