Near-resonant light transmission in two-dimensional dense cold atomic media with short-range positional correlations

Abstract

Light propagation in disordered media is a fundamental and important problem in optics and photonics. In particular, engineering light-matter interaction in disordered cold atomic ensembles is one of the central topics in modern quantum and atomic optics. The collective response of dense atomic gases under light excitation, which crucially depends on the spatial distribution of atoms and the geometry of the ensemble, has important impacts on quantum technologies like quantum sensors, atomic clocks and quantum information storage.Here we analyze near-resonant light transmission in two-dimensional dense ultracold atomic ensembles with short-range positional correlations. Based on the coupled-dipole simulations under different atom number densities and correlation lengths, we show that the collective effects are strongly influenced by those positional correlations, manifested as significant shifts and broadening or narrowing of transmission resonance lines. The results show that mean-field theories like Lorentz-Lorenz relation are not capable of describing such collective effects. We further investigate the statistical distribution of eigenstates, which are significantly affected by the interplay between dipole-dipole interactions and position correlations. This work can provide profound implications on collective and cooperative effects in cold atomic ensembles as well as the study of mesoscopic physics concerning light transport in strongly scattering disordered media. simplest hard-sphere-type correlation which exists in densely packed hard spheres [32] can usually increase the transport mean free path of light [33,34]. Screened Coulomb potential induced positional correlations in nanoparticle colloidal suspensions were found to induce strongly negative asymmetry factor [35,36]. Recently, some unexpected optical properties like optical transparency [37], enhanced absorption [38] and isotropic photonic band gaps [39][40][41][42] were discovered in 2D and 3D disordered media with certain structural correlations, e.g., the stealthy hyperuniform media. Therefore, structural correlations offer a great opportunity for tailoring the optical properties of disordered materials, with promising applications like structural coloration [43,44], bright white paints [45] and solar energy harvesting [38,[46][47][48][49], etc.Despite these fascinating advancements, however, it is still not fully understood how structural correlations affect optical properties of disordered media, even for an ideally simple system composed of randomly distributed spherical scatterers [45,[50][51][52][53]. In particular, the interplay between structural correlations and near-field as well as far-field electromagnetic interactions among scatterers is still not very clear [50,51,54], especially near single scatterer internal resonances (like Mie resonances for dielectric nanoparticles) at high packing density [55][56][57][58][59].On the other hand, the last three decades have witnessed the rapid development of laser cooling and trapping of atoms to r...

Impact of particle size and multiple scattering on the propagation of waves in stealthy-hyperuniform media

“…Important effects around resonant frequencies can also appear and were recently studied in Refs. [22,32]. Interestingly, SRC media can be seen as an intermediate state between purely random and SHU media, as illustrated in Figure 1.…”

Breakdown of Maxwell Garnett theory due to evanescent fields at deep-subwavelength scale

“…reflection, transmission and absorption) of the composite structures become sensitive to the positions of those tiny inclusions. Such varying local fields can be comprehended as the excitation of high-order modes [32] instead of dipole-dipole interaction [33]. However, in the traditional EMT description, these details are averaged out, thus leading to the breakdown of the EMT We note that the breakdown in the 2D/3D structures does not rely on the angle of incidence, which can be observed even under normal incidence as shown above.…”

Van der Waals dephasing for Dicke subradiance in cold atomic clouds

“…Imposing an exclusion volume actually induces some correlations in the atomic positions. This correlated disorder, in turn, affects the light scattering properties (see, e.g., [44][45][46]). In particular, increasing the density at fixed exclusion volume or increasing the exclusion volume at fixed density enhances the positional correlations.…”