Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userEnhanced Absorption of Waves in Stealth Hyperuniform Disordered Media
110
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We study the propagation of waves in a set of absorbing subwavelength scatterers positioned on a stealth hyperuniform point pattern. We show that spatial correlations in the disorder substantially enhance absorption compared to a fully disordered structure with the same density of scatterers. The non-resonant nature of the mechanism provides broad angular and spectral robustness. These results demonstrate the possibility to design low-density materials with blackbody-like absorption.
rate research
Read More
We develop a multiple scattering theory for the absorption of waves in disordered media. Based on a general expression of the average absorbed power, we discuss the possibility to maximize absorption by using structural correlations of disorder as a degree of freedom. In a model system made of absorbing scatterers in a transparent background, we show that a stealth hyperuniform distribution of the scatterers allows the average absorbed power to reach its maximum value. This study provides a theoretical framework for the design of efficient non-resonant absorbers made of dilute disordered materials, for broadband and omnidirectional light, and other kinds of waves.
An ultra-broadband transverse magnetic (TM) pass hyperuniform disordered photonic crystal (HUDPC) polarizer is proposed and demonstrated on a silicon-on-insulator platform. Propagation of the transverse electric mode is blocked by three combined effects, including the photonic bandgap (PBG) effect, diffusive (non-resonant) scattering, and bandedge resonances. Specially, the designed 30-dB bandwidth in polarization extinction ratio (PER) of 265 nm is much larger than the spectral width of the PBG (149 nm) due to using the bandedge resonances. The TM mode is in the subwavelength regime of the HUDPC and thus has a low insertion loss (IL). An ultrawide 30-dB bandwidth in PER of 210 nm (1.44-1.65 um) is experimentally demonstrated in a 12.9-um-long HUDPC polarizer with spectrally averaged PER of 39.6 dB and IL for the TM mode of 1.1 dB (IL = 0.6 dB at 1.55 um). The HUDPC polarizers can be an excellent candidate for ultra-broadband polarization filtering in the silicon photonic platform.
A fundamental challenge in physics is controlling the propagation of waves in disordered media despite strong scattering from inhomogeneities. Spatial light modulators enable one to synthesize (shape) the incident wavefront, optimizing the multipath interference to achieve a specific behavior such as focusing light to a target region. However, the extent of achievable control was not known when the target region is much larger than the wavelength and contains many speckles. Here we show that for targets containing more than $g$ speckles, where $g$ is the dimensionless conductance, the extent of transmission control is substantially enhanced by the long-range mesoscopic correlations among the speckles. Using a filtered random matrix ensemble appropriate for coherent diffusion in open geometries, we predict the full distributions of transmission eigenvalues as well as universal scaling laws for statistical properties, in excellent agreement with our experiment. This work provides a general framework for describing wavefront-shaping experiments in disordered systems.
We study the optimal diffusive transmission and absorption of broadband or polychromatic light in a disordered medium. By introducing matrices describing broadband transmission and reflection, we formulate an extremal eigenvalue problem where the optimal input wavefront is given by the corresponding eigenvector. We show analytically that a single wavefront can exhibit strongly enhanced total transmission or total absorption across a bandwidth that is orders of magnitude broader than the spectral correlation width of the medium, due to long-range correlations in coherent diffusion. We find excellent agreement between the analytic theory and numerical simulations.
The purpose of this work is to understand the fundamental connection between structural correlations and light localization in three-dimensional (3D) open scattering systems of finite size. We numerically investigate the transport of vector electromagnetic waves scattered by resonant electric dipoles spatially arranged in 3D space by stealthy hyperuniform disordered point patterns. Three-dimensional stealthy hyperuniform disordered systems (3D-SHDS) are engineered with different structural correlation properties determined by their degree of stealthiness $chi$. Such fine control of exotic states of amorphous matter enables the systematic design of optical media that interpolate in a tunable fashion between uncorrelated random structures and crystalline materials. By solving the electromagnetic multiple scattering problem using Greens matrix spectral method, we establish a transport phase diagram that demonstrates a clear delocalization-localization transition beyond a critical scattering density that depends on $chi$. The transition is characterized by studying the Thouless number and the spectral statistics of the scattering resonances. In particular, by tuning the $chi$ parameter, we demonstrate large spectral gaps and suppressed sub-radiant proximity resonances, facilitating light localization. Moreover, consistently with previous studies, our results show a region of the transport phase diagram where the investigated scattering systems become transparent. Our work provides a systematic description of the transport and localization properties of light in stealthy hyperuniform structures and motivates the engineering of novel photonic systems with enhanced light-matter interactions for applications to both classical and quantum devices.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
