Two-dimensional Thouless pumping of light in photonic moiré lattices

Abstract

Continuous and quantized transports are profoundly different. The latter is determined by the global rather than local properties of a system, it exhibits unique topological features, and its ubiquitous nature causes its occurrence in many areas of science. Here we report the first observation of fully-two-dimensional Thouless pumping of light by bulk modes in a purpose-designed tilted moiré lattices imprinted in a photorefractive crystal. Pumping in such unconfined system occurs due to the longitudinal adiabatic and periodic modulation of the refractive index. The topological nature of this phenomenon manifests itself in the magnitude and direction of shift of the beam center-of-mass averaged over one pumping cycle. Our experimental results are supported by systematic numerical simulations in the frames of the continuous Schrödinger equation governing propagation of probe light beam in optically-induced photorefractive moiré lattice. Our system affords a powerful platform for the exploration of topological pumping in tunable commensurate and incommensurate geometries.

Fast topological pumps via quantum metric engineering on photonic chips

“…It describes the quantized transfer of particles per cycle of evolution in the parameter space and remains robust against deformation of the evolution loop in the adiabatic regime. While initially proposed in solid-state electronic systems, the Thouless pump has been observed in diverse systems, including ultracold atoms (13)(14)(15), mechanics (16), acoustics (17)(18)(19)(20)(21), and photonic waveguides (22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34). Thouless pumps in d spatial dimensions manifest states that cross the energy gap and localize on their (d − 1)dimensional boundaries (16,22,27,35).…”

Nanoimprint Meta‐Device for Chiral Imaging

“…Fabricating large-area meta-devices, especially for the bilayer meta-devices, presents a significant challenge for massive productions. Fabricating bilayer meta-devices usually needs successive electron-beam lithography steps, [42][43][44] which are expensive and time-consuming, limiting manufacturing efficiency, production capacity, and sample size. Photolithography has the potential to overcome the existing limitations in patterning due to its capability to fabricate large-scale and mass-scalable metasurfaces.…”

Approaching the adiabatic infimum of topological pumps on thin-film lithium niobate waveguides

“…Topological photonics, with the emergence of edge states between topologically distinct systems, has opened a promising avenue for robust optical transport and light manipulations [1][2][3][4] . Initially proposed by Thouless 5 , topological pumps with quantized charge flow in a periodically driven system [6][7][8][9][10][11][12][13][14][15] has garnered significant attention and plays a crucial role in realizing robust excitation transfer in finite systems sustaining topological edge states [16][17][18][19][20][21][22][23][24][25][26] . The resilience of topological edge state pumps, protected by the winding of the pump loop around gapless points in parameter space [6][7][8]12 , makes them immune to disorders and defects 12,23 .…”