Última publicação

Lévy flights of photons with infinite mean free path

Multiple scattering of light by resonant vapor is characterized by Lévy-type superdiffusion with a single-step
size distribution p(x) ∝ 1/x1+α. We investigate Lévy flight of light in a hot rubidium vapor collisional-broadened
by 50 torr of He gas. The frequent collisions produce Lorentzian absorptive and emissive profiles with α < 1 and
a corresponding divergent mean step size. We extract the Lévy parameter α ≈ 0.5 in a multiple-scattering regime
from radial profile of the transmission and from violation of the Ohm’s law. The measured radial transmission
profile and the total diffusive transmission curves are well reproduced by numerical simulations for Lorentzian
line shapes.