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 behavior breaks down. Our observations establish optical mesh lattices as a promising platform to study fluids of light in novel regimes of interdisciplinary interest, including non-Hermitian and/or topological physics.
Bibliographical noteFunding Information:
Deutsche Forschungsgemeinschaft Royal Society European Commission H2020 European Research Council Provincia Autonoma di Trento Google
This project was supported by German Research Foundation (DFG) in the framework of Project No. PE 523/14-1 and by the International Research Training Group (IRTG) 2101. H. M. P. is supported by the Royal Society via Grants No. UF160112, No. RGF\EA\180121, and No. RGF\R1\180071. I. C. acknowledges financial support from the European Union FET-Open Grant “MIR-BOSE” (No. 737017), from the H2020-FETFLAG-2018-2020 project “PhoQuS” (No. 820392), from the Provincia Autonoma di Trento, from the Q@TN initiative, and from Google via the quantum NISQ award.
© 2021 American Physical Society.
ASJC Scopus subject areas
- Physics and Astronomy(all)