Optimization and photomodification of extremely broadband optical response of plasmonic core-shell obscurants.
Plasmonic resonances of the metallic shells depend on their nanostructure and geometry of the core, which can be optimized for the broadband extinction normalized by mass. The fractal nanostructures can provide a broadband extinction. It allows as well for a laser photoburning of holes in the extinction spectra and consequently windows of transparency in a controlled manner. The studied core-shell microparticles synthesized using colloidal chemistry consist of gold fractal nanostructures grown on precipitated calcium carbonate (PCC) microparticles or silica (SiO2) microspheres. The optimization includes different core sizes and shapes, and shell nanostructures. It shows that the rich surface of the PCC flakes is the best core for the fractal shells providing the highest mass normalized extinction over the extremely broad spectral range. The mass normalized extinction cross section up to 3m2/g has been demonstrated in the broad spectral range from the visible to mid-infrared. Essentially, the broadband response is a characteristic feature of each core-shell microparticle in contrast to a combination of several structures resonant at different wavelengths, for example nanorods with different aspect ratios. The photomodification at an IR wavelength makes the window of transparency at the longer wavelength side.
University of North Texas, Department of Physics and Advanced Materials & Manufacturing Institute, 1155 Union Circle, Denton, TX 76203, USA. Electronic address: vashistadesilva@my.unt.edu.
Vashista C
VC
de Silva
Military University of Technology, Institute of Optoelectronics, 2 Kaliskiego Str., 00-908 Warsaw, Poland. Electronic address: piotr.nyga@wat.edu.pl.
Piotr
P
Nyga
University of North Texas, Department of Physics and Advanced Materials & Manufacturing Institute, 1155 Union Circle, Denton, TX 76203, USA; Skolkovo Institute of Science and Technology, 3 Nobel St., Moscow 143026, Russia. Electronic address: vladimir.drachev@unt.edu.
Vladimir P
VP
Drachev
Broadband absorption; Core-shell; Mass extinction coefficient; Nanoparticle; Nobel metal; Obscurants; Photomodification; Plasmonic; Silica