Superfluidity of Light and Its Breakdown in Optical Mesh Lattices

Abstract

Hydrodynamic phenomena can be observed with light thanks to the analogy between quantum gases and nonlinear optics. In this Letter, we report an experimental study of the superfluid-like properties of light in a (1+1)-dimensional nonlinear optical mesh lattice, where the arrival time of optical pulses plays the role of a synthetic spatial dimension. A spatially narrow defect at rest is used to excite sound waves in the fluid of light and measure the sound speed. The critical velocity for superfluidity is probed by looking at the threshold in the deposited energy by a moving defect, above which the apparent superfluid behaviour breaks down. Our observations establish optical mesh lattices as a promising platform for fluids of light.

Bright and dark solitons in a photonic nonlinear quantum walk: lessons from the continuum

“…The NLOGB was later experimentally implemented by Wimmer et al [44] in a system involving the propagation of light pulses in optical fibers, an implementation in which the displacement operation consists in delaying or advancing the pulses, so that the QW occurs along the physical time dimension. More recently, the same group made a proposal of NLQW in optical mesh lattices [45], see also the related paper [46], a system that has been recently revisited by Jana et al [47]. The NLOGB model has also been the subject of several theoretical studies, including the study of its continuous limit as a nonlinear Dirac equation [48][49][50].…”

A Perspective on Synthetic Dimensions in Photonics

“…These advantages are complemented by outstanding flexibility: Active amplitude-and phase modulation serve to imprint real as well as imaginary on-site terms in the corresponding Hamiltonian, which can be dynamically adjusted for each site in synthetic space and time. By virtue of these remarkable capabilities, photonic time-division multiplexing schemes have been used to emulate a wide range of phenomena in synthetic (1+1)D lattices, including Anderson localization, [51,52] geometrical pumping, [49] and topological phases [53,54] or nonlinear effects [55,56] and neural networks [57] as well as non-Hermitian phenomena such as ones related to Parity-Time (PT) symmetry, [48] stochastic dissipation, [58] constant intensity waves, [59] and non-Hermitian topology. [50,60] Moreover, the feasibility of two synthetic spatial dimensions has been demonstrated for single photons [61,62] and classical light, [63][64][65] paving the way toward even higher dimensions.…”

Observation of Generalized Dynamic Localizations in Arbitrary‐Wave Driven Synthetic Temporal Lattices

“…To start, we consider the synthetic temporal lattice constructed by mapping from two coupled fiber loops with slightly different lengths. [26][27][28][29][30][31][32][33][34][35][36][37][38] As shown in Figure 1a, the fiber-loop circuit is fed with an optical pulse from the longer loop generated from a laser diode. Upon entering the circuit and passing through the central coupler, the injected pulse will be split into two parts and enter two different loops.…”

“…To circumvent the drawbacks of high loss and poor tunability of spatial waveguide lattices, one may construct an artificial lattice using synthetic dimensions for realizing generalized DLs. Synthetic lattices, formed by coupling a set of discrete photonic modes with equally spaced frequency, [17][18][19][20][21][22][23][24][25] time, [26][27][28][29][30][31][32][33][34][35][36][37][38] and orbital angular momentum, [39][40][41][42] have attracted intensive recent attention in emulating many fundamental lattice dynamics for photons. Benefiting from the convenient controllability and reconfigurability of lattice parameters, a lot of physical concepts that are difficult to realize in spatial lattices have been demonstrated in synthetic lattices, such as parity-time symmetry, [27][28][29] topological windings, [24] and non-Hermitian skin effect.…”