Blast waves in a paraxial fluid of light ^(a)

Abstract

We study experimentally blast wave dynamics on a weakly interacting fluid of light. The fluid density and velocity are measured in 1D and 2D geometries. Using a state equation arising from the analogy between optical propagation in the paraxial approximation and the hydrodynamic Euler's equation, we access the fluid hydrostatic and dynamic pressure. In the 2D configuration, we observe a negative differential hydrostatic pressure after the fast expansion of a localized over-density, which is a typical signature of a blast wave for compressible gases. Our experimental results are compared to the Friedlander waveform hydrodynamical model (Friedlander F. G., Proc. R. Soc. A: Math. Phys. Sci., 186 (1946) 322). Velocity measurements are presented in 1D and 2D configurations and compared to the local speed of sound, to identify the supersonic region of the fluid. Our findings show an unprecedented control over hydrodynamic quantities in a paraxial fluid of light.

Non-equilibrium pre-thermal states in a two-dimensional photon fluid

“…This platform relies on the formal analogy between a laser field propagating through a nonlinear medium and the temporal evolution of a 2D quantum fluid. This propagating geometry is well suited to study non-equilibrium physics, since the initial state can be engineered at will using wavefront shaping techniques, as illustrated by recent observations of dispersive shock waves [35][36][37][38]. Moreover, upon entering the nonlinear medium, the beam experiences a sudden change of the nonlinear refractive index, which effectively reproduces the non-equilibrium dynamics of a Bose gas after an interaction quench [39].…”

Measurement of the Static Structure Factor in a Paraxial Fluid of Light Using Bragg-like Spectroscopy

“…Fluids of light in the paraxial configuration have emerged as an original approach to study degenerate Bose gases [1]. Several important results have recently established this platform as a potential analogue quantum simulator, including the demonstrations of superfluidity of light [2][3][4], the observation of the Berezinskii-Kosterlitz-Thouless transition [5], shockwaves [6][7][8] and precondensation [9], the evidence of photon droplets [10], and the creation of analogue rotating black hole geometries [11,12]. Paraxial fluids of light rely on the direct mathematical analogy that can be drawn between the Gross-Pitaevskii equation describing the mean field evolution of a Bose-Einstein condensate (BEC) and the nonlinear Schrödinger equation describing the propagation of light within a χ ð3Þ nonlinear medium [1,13,14].…”

Inverse energy cascade in two-dimensional quantum turbulence in a fluid of light

“…In this work, we introduce a novel platform for quantum turbulence based on paraxial fluids of light in hot atomic vapors, which are 2D-superfluids [14,32] in which the hydrodynamic regime has been observed experimentally [33][34][35][36]. We demonstrate the existence of an inverse energy cascade in a turbulent 2D-quantum fluid and we explain the microscopic origin of the scaling laws in the incompressible kinetic energy spectrum.…”