State-recycling and time-resolved imaging in topological photonic lattices

Abstract

Photonic lattices—arrays of optical waveguides—are powerful platforms for simulating a range of phenomena, including topological phases. While probing dynamics is possible in these systems, by reinterpreting the propagation direction as time, accessing long timescales constitutes a severe experimental challenge. Here, we overcome this limitation by placing the photonic lattice in a cavity, which allows the optical state to evolve through the lattice multiple times. The accompanying detection method, which exploits a multi-pixel single-photon detector array, offers quasi-real time-resolved measurements after each round trip. We apply the state-recycling scheme to intriguing photonic lattices emulating Dirac fermions and Floquet topological phases. We also realise a synthetic pulsed electric field, which can be used to drive transport within photonic lattices. This work opens an exciting route towards the detection of long timescale effects in engineered photonic lattices and the realisation of hybrid analogue-digital simulators.

Eigenvalue measurement of topologically protected edge states in split-step quantum walks

“…Phenomena such as the quantum Hall effect [1] and topological insulators [2,3] aroused vivid interest in the study of the topological properties of physical systems. While these effects have been originally observed in semiconductor systems, experimental studies have been conducted on systems such as ultra cold atoms [4][5][6][7], photonic model systems [8][9][10][11][12], solid-state systems [13,14], superconducting circuits [15], mechanical oscillators [16] and microwave networks [17][18][19]. In photonic systems, topological phenomena can be accessed by implementing a split-step quantum walk on a 1D optical lattice [20][21][22].…”

Periodic driving induced helical Floquet channels with ultracold atoms in momentum space

“…The high tunability of our configuration enables us to observe robust helical Floquet channels in the 1D momentum lattice [52,61]. To observe the phenomenon, we evolve the system under the Floquet operator U h = Q(π/2)W (π/2), implemented with T ≈ 0.44ms (Ω = 2π × 2.3(1)kHz 8E r / ) and t w = t q .…”

Simulation of two-boson bound states using arrays of driven-dissipative coupled linear optical resonators

“…As one can evince from pioneering experiments [44 and 56], these systems are an excellent platform to probe dynamical properties such as the effective doublon hopping rate, the beating phenomena related to the overlap of the input state with few eigenstates, and the real-time formation of Feshbach pairs. Doublon edge states may be instead difficult to identify because their small hopping rate makes a long time evolution needed to assess localization, a problem that could, for instance, be circumvented by the recently introduced state-recycling technique [57].…”