Hybrid exciton-plasmon-polaritons in van der Waals semiconductor gratings

Abstract

Van der Waals materials and heterostructures that manifest strongly bound exciton states at room temperature also exhibit emergent physical phenomena and are of great promise for optoelectronic applications. Here, we demonstrate that nanostructured, multilayer transition metal dichalcogenides (TMDCs) by themselves provide an ideal platform for excitation and control of excitonic modes, paving the way to exciton-photonics. Hence, we show that by patterning the TMDCs into nanoresonators, strong dispersion and avoided crossing of exciton, cavity photons and plasmon polaritons with effective separation energy exceeding 410 meV can be controlled with great precision. We further observe that inherently strong TMDC exciton absorption resonances may be completely suppressed due to excitation of hybrid light-matter states and their interference. Our work paves the way to the next generation of integrated exciton optoelectronic nano-devices and applications in light generation, computing, and sensing.

Ultra-broadband photon harvesting in large-area few-layer MoS2 nanostripe gratings

“…It is thus ascertained that the kind of ultra-broadband absorption enhancement achieved in our samples cannot be explained in terms of Mie resonances from the individual MoS 2 nanostructures acting as low-quality factor nanocavities, like in previous works. [56][57][58][59][60] Actually, our 4ML MoS 2 nanostripes are too thin to operate as nanocavities, whereas our subtractive approach enabling light coupling into a highly multimodal substrate can be eventually scaled down to the ML level.…”

Surface plasmon polariton pulse shaping via two-dimensional Bragg grating pairs

“…Although carried out in thin silver using prototypical nanohole arrays, it is important to emphasize that our pulse shaping modalities are generally applicable. Utilizing highindex dielectric or semiconductor-based media in combination with pure metals would allow the SPP dispersion to be tuned, in effect, adding another level of control over the spatial and temporal properties of the surface fields(s) [38][39][40]. Varying the substrate composition also has the advantage of extending the spectral range over which SPPs and analogous matter waves may be sustained.…”

“…Varying the substrate composition also has the advantage of extending the spectral range over which SPPs and analogous matter waves may be sustained. Such an integrated photonic device was explored recently using atomically thin Van der Waals crystals [38]. Another interesting avenue that recognizes the demand for actively controlled polaritonic devices would be to integrate gatetunable materials, such as graphene, with the electromagnetic field modulation we achieved through SPP spatial interference.…”

Thickness‐Dependent Elastic Softening of Few‐Layer Free‐Standing MoSe2

“…[ 1 ] Moreover, ultrathin TMDCs are used as a research platform for studying light‐matter interactions, exciton‐polariton transport, and developing next‐generation photonic devices. [ 7–11 ] Uniform, thin vdW materials, down to one layer, are easy to fabricate by liquid [ 12 ] or mechanical [ 13 ] exfoliation from bulk. Owing to their relatively simple preparation, high‐quality factor at low temperatures, and high elastic moduli, ultrathin membranes of TMDCs can be used as mechanical resonators for sensors.…”