Exciton-enabled meta-optics in two-dimensional transition metal dichalcogenides

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 MoS2 multilayers is demonstrated for high-quality optical nanodevices, assisted fundamentally by strong excitonic resonances at the band-nesting region of MoS2. The atomic thin MoS2 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 meta-optics and nanophotonics.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)The work is financially supported by the Agency for Science, Technology and Research (A*STAR) Singapore under Grants 152700014 and 152700012. K.H. thanks CAS Pioneer Hundred Talents Program, “the Fundamental Research Funds for the Central Universities” in China, USTC Research Funds of the Double First-Class Initiative (Grant YD2030002003), the National Natural Science Foundation of China (Grant 61875181 and 61705085), and the support from the University of Science and Technology of China’s Centre for Micro and Nanoscale Research and Fabrication. G.Y., G.A., and C.S. acknowledge the support from the Agency for Science, Technology and Research (A*STAR) Singapore (Grant SERC A1685b0005) and Singapore Ministry of Education Academic Research Fund Tier 3 (MOE2016-T3- 1-006 (S)). H.S. acknowledges the support from the Singapore Ministry of Education through the Academic Research Fund under Project Tier 1-RG189/17(S). We thank Prof. Nikolay Zheludev for the valuable discussions. Z.W. thanks the support from Ms. Zhang Xin and Dr. Zhao Rui