Sub-thermal to super-thermal light statistics from a disordered lattice via deterministic control of excitation symmetry

Abstract

Monochromatic coherent light traversing a disordered photonic medium evolves into a random field whose statistics is dictated by the disorder level. Here, we demonstrate experimentally that light statistics can be deterministically tuned in certain disordered lattices even when the disorder level is held fixed -by controllably breaking the excitation-symmetry of the lattice modes. We exploit a lattice endowed with disorder-immune chiral symmetry in which the eigenmodes come in skewsymmetric pairs. If a single lattice site is excited, a 'photonic thermalization gap' emerges: the realm of sub-thermal light statistics is inaccessible regardless of the disorder level. However, by exciting two sites with a variable relative phase, as in a traditional two-path interferometer, the chiral symmetry is judiciously broken and interferometric control over the light statistics is exercised, spanning subthermal and super-thermal regimes. These results may help develop novel incoherent lighting sources from coherent lasers.

Far-from-Equilibrium Route to Superthermal Light in Bimodal Nanolasers

“…Superthermal light statistics has already been observed in a number of photonic systems such as rotating diffusive plates [4], superradiant quantum dots [5], or micropillars showing switching instabilities between two orthogonally polarized modes [6,7]. Superthermal fluctuations have also been reported in the spatial domain as a result of light propagation in disordered waveguide arrays [8,9]. In all these cases, (quantum or classical) light and/or matter coupling mechanisms at (quasi)equilibrium are the main ingredients to generate extra correlations.…”

Transfer efficiency enhancement and eigenstate properties in locally symmetric disordered finite chains

“…Initially explored for electrons in models of solids [1][2][3] , disorder-induced localization has more recently also been demonstrated and intensively studied for light waves [4][5][6][7][8][9][10] as well as for matter waves in optical lattices [11][12][13] . Typically manifest in one-dimensional (1d) discrete lattice models with random onsite potential (diagonal disorder) or inter-site hoppings (off-diagonal disorder) 14,15 , localization also occurs for structural disorder in systems with binary constituents 6,16 and may further be induced in the bulk of setups with disordered boundary 17 .…”

Interferometric control of the photon-number distribution

“…x . However, for the impact of this skewsymmetry to be manifested, the members of the skew-symmetric paired modes with indices ±j must be excited with equal weights, which we refer to as 'activating' the chiral symmetry 18,31 . To visualize the activation of chiral symmetry, we associate a phasor with each mode at each lattice site.…”