Observation of edge solitons in photonic graphene

Abstract

Edge states emerge in diverse areas of science, offering new opportunities for the development of novel electronic or optoelectronic devices, sound and light propagation controls in acoustics and photonics [1,2]. Previous experiments on edge states and exploration of topological phases in photonics were carried out mostly in linear regimes, but the current belief is that nonlinearity introduces new striking features into physics of edge states, leading to the formation of edge solitons [3,4], optical isolation [5], and topological lasing [6-9], to name a few. Here we experimentally demonstrate edge solitons at the zigzag edge of a reconfigurable "photonic graphene" lattice [10-13] created via the effect of electromagnetically induced transparency [14] in an atomic vapor cell with controllable nonlinearity [15]. To obtain edge solitons, Raman gain [16] was introduced to compensate strong absorption experienced by the edge state during propagation. Our observations pave the way to experimental exploration of topological photonics on nonlinear, reconfigurable platform.

Multi-wave-mixing-induced nonlinear modulation of diffraction peaks in an opto-atomic grating

“…In the present model our objective is to generate nonlinear generation of diffraction peaks as a result of the non-degenerate four-wave mixing (FWM) process where the excited energy levels are different from those used in Rydberg atoms. In recent days, photonic graphene lattice originated via the effect of EIT in an atomic vapor cell is a highly promising candidate for generation of various nonlinear optical effects 27 – 29 . Evolution of optical -symmetry has been employed to construct EIG in Raman-Nath regime as investigated in Ref.…”

Nonlinear self-accelerating beams induced in multilevel atomic vapors

“…For an optical beam at propagation distance , in the next step , the optical field distribution can be obtained with the Split-step method. In the first half of the step , we only consider the effect of the linear operator (16) and then we consider the nonlinear operator in the whole step (17) finally, in the second half of the step , the linear operator is considered again and the optical field distribution can be obtained as…”

“…photonic bandgap structures [10], photonic topological insulators [11], cubic-quintic (CQ) condensate solitons [12], (anti-) parity-time symmetric systems [13][14][15], optical Bloch oscillations and Zener tunneling [16], and edge solitons in photonic graphene [17]. The dressed atomic system is a good platform for studying various self-accelerating beams because its optical properties are well-known.…”

Observation of chiral edge states in gapped nanomechanical graphene

“…Recently, the research of graphene has been extended from solid-state materials to metamaterial systems in other areas, including photonics ( 12 , 13 ), acoustics ( 14 , 15 ), and mechanics ( 16 ). Various graphene-related phenomena that are challenging in solid-state physics have been experimentally demonstrated in these synthetic metamaterials, such as Zitterbewegung oscillation ( 16 ), Klein tunneling ( 17 ), unconventional bearded edge states ( 12 ), and solitons ( 18 ). Among these photonic and phononic metamaterials, nanomechanical system with electrical tunability ( 19 ) and strong nonlinearity ( 20 ) is one of the most promising platforms to explore graphene-related physics.…”