Nanowerk December 12, 2023 The canonical studies on Mie scattering unravel strong electric/magnetic optical responses in nanostructures, laying foundation for emerging meta-photonic applications. Conventionally, the morphology-sensitive resonances hinge on the normalized frequency, i.e. particle size over wavelength, but non-paraxial incidence symmetry is overlooked. Through confocal reflection microscopy with a tight focus scanning over silicon nanostructures, an international team of researchers (Taiwan, Japan, China) showed the scattering point spread functions’ distinctive spatial patterns featuring linear scattering efficiency was maximal when the focus was misaligned. The underlying physical mechanism was the excitation of higher-order multipolar modes, not accessible by plane wave irradiation, […]
Category Archives: Nanostructures
Shaping with light – a novel method for crafting chiral nanostructures with lasers
Nanowerk March 22, 2023 Chiral nanostructures based on semiconductors exhibit pronounced properties of chiral luminescence and optoelectronic responses, which are fundamental for chiroptoelectronic devices. Researchers in China showed polarization-directed oriented growth of platinum oxide/sulfide nanoparticles based on optical dipole interactions and near-field–enhanced photochemical deposition. By rotating the polarization during the irradiation or employing vector beam, both three dimensional and planar chiral nanostructures could be obtained, which is extendable to cadmium sulfide. The chiral superstructures exhibited broadband optical activity with a g-factor of ~0.2 and a luminescence g-factor of ~0.5 in the visible, making them promising candidate for chiroptoelectronic devices… read […]
GHz burst mode femtosecond laser pulses can create unique two-dimensional periodic surface nanostructures
Phys.org January 24, 2023 Most studies using the GHz burst mode femtosecond laser pulses focus on ablation of materials to achieve high-efficiency and high-quality material removal. Researchers in Japan explored the ability of the GHz burst mode femtosecond laser processing to form laser-induced periodic surface structures (LIPSS) on silicon. The direction of LIPSS formed by the single-pulse mode with linearly polarized laser pulses is typically perpendicular to the laser polarization direction. They showed that the GHz burst mode femtosecond laser created unique two-dimensional LIPSS. The team has proposed a possible mechanism for the formation of 2D LIPSS formed by the […]