Exciton-Enabled Meta-Optics in Two-Dimensional Transition Metal Dichalcogenides

Abstract

Optical wavefront engineering has been rapidly developing in fundamentals from phase accumulation in the optical path to the electromagnetic resonances of confined nanomodes in optical metasurfaces. However, the amplitude modulation of light has limited approaches that usually originate from the ohmic loss and absorptive dissipation of materials. Here, an atomically thin photon-sieve platform made of MoS 2 multilayers is demonstrated for high-quality optical nanodevices, assisted fundamentally by strong excitonic resonances at the band-nesting region of MoS 2 . The atomic thin MoS 2 significantly facilitates high transmission of the sieved photons and high-fidelity nanofabrication. A proof-of-concept two-dimensional (2D) nanosieve hologram exhibits 10-fold enhanced efficiency compared with its non-2D counterparts. Furthermore, a supercritical 2D lens with its focal spot breaking diffraction limit is developed to exhibit experimentally far-field label-free aberrationless imaging with a resolution of ∼0.44λ at λ = 450 nm in air. This transition-metal-dichalcogenide (TMDC) photonic platform opens new opportunities toward future 2D metaoptics and nanophotonics.

Beam steering at the nanosecond time scale with an atomically thin reflector

“…Conventional optical devices, typically made from materials with relatively weak light-matter interactions and a smooth optical response on the wavelength scale, are bulky to accumulate the desired effect on the optical wavefront. Recent advances in flat optics demonstrate that steep gradients in the phase, amplitude, or polarization can be used to control light fields on sub-wavelength scales 1 – 3 , enabling novel optical phenomena and applications, including ultrathin lenses 4 , 5 , metasurfaces 6 , non-reciprocity 7 , and negative refraction 8 .…”

The Dawn of Metadevices: From Contemporary Designs to Exotic Applications

“…The field of nanophotonics offers various sophisticated methods and technologies for fabricating and integrating these metasurfaces [40]. These technologies include electron-beam lithography (EBL) [52], focused-ion beam (FIB) lithography [53], interference lithography, nanoimprint lithography [54], and femtosecond laser writing [55].…”

Sidelobe suppression for coherent beam combining with laser beams placed along a Fermat spiral

“…As a result, the main lobe of the coherent combining beam is surrounded by obvious sidelobes, which cannot be eliminated fundamentally. Sidelobe suppression is an important issue, not only in CBC systems, but also in many other fields of research, such as super-oscillation in optics, which is one kind of destructive interference of light with different frequencies at some points at small intervals [14][15][16] . Increasing the number of the laser beams is a promising approach to improve the output power of the main lobe [17] .…”