title: Wavefront shaping through emulated curved space in waveguide settings.
abstract: The past decade has witnessed remarkable progress in wavefront shaping, including shaping of beams in free space, of plasmonic wavepackets and of electronic wavefunctions. In all of these, the wavefront shaping was achieved by external means such as masks, gratings and reflection from metasurfaces. Here, we propose wavefront shaping by exploiting general relativity (GR) effects in waveguide settings. We demonstrate beam shaping within dielectric slab samples with predesigned refractive index varying so as to create curved space environment for light. We use this technique to construct very narrow non-diffracting beams and shape-invariant beams accelerating on arbitrary trajectories. Importantly, the beam transformations occur within a mere distance of 40 wavelengths, suggesting that GR can inspire any wavefront shaping in highly tight waveguide settings. In such settings, we demonstrate Einstein's Rings: a phenomenon dating back to 1936.
authors.affiliation: National Laboratory of Solid State Microstructures &School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, China.
authors.forename: Chong
authors.initials: C
authors.lastname: Sheng
authors.affiliation: Department of Physics and Solid State Institute, Technion, Haifa 32000, Israel.
authors.forename: Rivka
authors.initials: R
authors.lastname: Bekenstein
authors.affiliation: National Laboratory of Solid State Microstructures &School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, China.
authors.forename: Hui
authors.identifier: http://orcid.org/0000-0003-3660-4730
authors.initials: H
authors.lastname: Liu
authors.affiliation: National Laboratory of Solid State Microstructures &School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, China.
authors.forename: Shining
authors.initials: S
authors.lastname: Zhu
authors.affiliation: Department of Physics and Solid State Institute, Technion, Haifa 32000, Israel.
authors.forename: Mordechai
authors.initials: M
authors.lastname: Segev