arXiv subjects

Jakub Haberko

Publications and source records attributed to Jakub Haberko.

5 recordsLinked to original sources

arXiv2022

Light transport through amorphous photonic materials with localization and bandgap regimes

We propose a framework that unifies the description of light transport in three-dimensional amorphous dielectric materials that exhibit both localization and a photonic bandgap. To this end, we argue that coherent reflection near and in the bandgap attenuates the generation of diffuse or localized photons. Using the self-consistent theory of localization and considering the density of states of photons, we can quantitatively describe all transport regimes: Transparency, light diffusion, localization, and bandgap. Comparing the model with numerical data on optical transport in hyperuniform dielectric networks confirms our findings.

physics.optics↗

arXiv2020

Transition from Light Diffusion to Localization in Three-Dimensional Amorphous Dielectric Networks near the Band Edge

Localization of light is the photon analog of electron localization in disordered lattices for whose discovery Anderson received the Nobel prize in 1977. The question about its existence in open three-dimensional materials has eluded an experimental and full theoretical verification for decades. Here we study numerically electromagnetic vector wave transmittance through realistic digital representations of hyperuniform dielectric networks, a new class of highly correlated but disordered photonic band gap materials. We identify the evanescent decay of the transmitted power in the gap and diffusive transport far from the gap. Near the gap, we find that transport sets off diffusive but, with increasing slab thickness, crosses over gradually to a faster decay, signaling localization. We show that we can describe the transition to localization at the mobility edge using the self-consistent theory of localization based on the concept of a position-dependent diffusion coefficient.

physics.optics↗

arXiv2016

Photonic hyperuniform networks by silicon double inversion of polymer templates

Hyperuniform disordered networks belong to a peculiar class of structured materials predicted to possess partial and complete photonic bandgaps for relatively moderate refractive index contrasts. The practical realization of such photonic designer materials is challenging however, as it requires control over a multi-step fabcrication process on optical length scales. Here we report the direct-laser writing of hyperuniform polymeric templates followed by a silicon double inversion procedure leading to high quality network structures made of polycrystalline silicon. We observe a pronounced gap in the shortwave infrared centered at a wavelength of $λ_{\text{Gap}}\simeq $ 2.5 $μ$m, in nearly quantitative agreement with numerical simulations. In the experiments the typical structural length scale of the seed pattern can be varied between 2 $μ$m and 1.54 $μ$m leading to a blue-shift of the gap accompanied by an increase of the silicon volume filling fraction.

physics.optics↗

arXiv2016

The Role of Short-Range Order and Hyperuniformity in the Formation of Band Gaps in Disordered Photonic Materials

We study photonic band gap formation in two-dimensional high refractive index disordered materials where the dielectric structure is derived from packing disks in real and reciprocal space. Numerical calculations of the photonic density of states demonstrate the presence of a band gap for all polarizations in both cases. We find that the band gap width is controlled by the increase in positional correlation inducing short-range order and hyperuniformity concurrently. Our findings suggest that the optimization of short-range order, in particular the tailoring of Bragg scattering at the isotropic Brillouin zone, are of key importance for designing disordered PBG materials.

physics.optics↗

arXiv2012

Fabrication of mesoscale polymeric templates for three-dimensional disordered photonic materials

We report on the mesoscale fabrication and characterization of polymeric templates for isotropic photonic materials derived from hyper- uniform point patterns using direct laser writing in a polymer photoresist. We study experimentally the microscopic structure by electron microscopy and small angle light scattering. Reducing the refractive index mismatch by liquid infiltration we find good agreement between the scattering data and numerical calculations based on a discrete dipole approximation. Our work demonstrates the feasibility of fabricating such random designer materials on technologically relevant length scales.

physics.optics↗