Abstract

Previous electromagnetic computations of multilayered dielectric/metallic spheres identified the ideal dimensions and composition for achieving optimized mass extinction coefficients (${{\rm{m}}^2}\!/{\rm{g}}$). A hollow metallic sphere, with a thin metallic shell, is one such example of a spherical structure that can theoretically achieve high mass extinction coefficients in the long wave infrared (LWIR) region (8–12 µm). To this end, we endeavored to demonstrate a cost-effective and scalable manufacturing approach for synthesizing and experimentally validating the mass extinction coefficients of hollow metallic spheres. Specifically, we detail a novel approach for fabricating hollow aluminum spheres using radio frequency (RF) magnetron sputter deposition. Sacrificial high-density polyethylene polymer microspheres were used as substrates for the deposition of thin layers of aluminum. The core shell structures were subsequently thermally processed to form the hollow micron sized aluminum shells. The mass extinction coefficients of the hollow aluminum spheres were subsequently measured and compared to computational results. A strong agreement between experimental and theoretical predictions was observed. Finally, the LWIR mass extinction coefficients of the hollow spheres were compared to high aspect ratio brass flakes, a common pigment used for LWIR attenuation, and other materials and geometries that are used for LWIR filtering applications. This comparison of both performance and availability revealed that the fabricated hollow aluminum spheres exhibited competitive LWIR properties using a more scalable and cost-effective manufacturing approach.

© 2020 Optical Society of America

Iterative design of multilayered dielectric microspheres with tunable transparency windows

Nicholas J. Hudak, Benjamin S. Garrett, Brendan G. DeLacy, and Mark S. Mirotznik
J. Opt. Soc. Am. A 36(5) 705-715 (2019)

Enhanced absorption per unit mass for infrared arrays using subwavelength metal–dielectric structures

Avijit Das and Joseph J. Talghader
J. Opt. Soc. Am. B 38(1) 183-193 (2021)

Mass-specific light absorption coefficients of mineral particles in aqueous suspension for the ultraviolet to near-infrared radiation spectral region (200–2500 nm)

Christian Utschig and Rüdiger Röttgers
Appl. Opt. 59(33) 10554-10564 (2020)

Band-rejection filter with high extinction ratio using prism-waveguide cascaded coupling system

Maowu Ran, Wenjuan Cai, Yincong Zhang, Xianping Wang, Yanchao She, Cheng Yin, and Jian Wu
J. Opt. Soc. Am. A 37(5) 748-751 (2020)

Light scattering by a random distribution of particles embedded in absorbing media: full-wave Monte Carlo solutions of the extinction coefficient

Stéphane Durant, Olivier Calvo-Perez, Nicolas Vukadinovic, and Jean-Jacques Greffet
J. Opt. Soc. Am. A 24(9) 2953-2962 (2007)