| Abstract [eng] |
The interaction of the photonic wheel with chiral clusters of nanoparticles and spherical particles is presented in this work. The photonic wheel is a beam which is interesting because of its unique angular momentum distribution. At the focal point of lens, the only observed angular momentum component is transverse to its propagation direction. The goal of this work is to familiarize with the theory describing Mie type scattering with the help of vector spherical harmonics. Also to calculate and visualize such type interactions. In the first part of the work, the Mie type scattering theory leading to calculating photonic wheel scattering of spherical particles and meta-atoms made out of them is given. Firstly it is introduced to the concept of photonic wheel, then theory leading to light confinement of highly focused beams. Also, it is introduced to the multiple sphere scattering method. The second part of the work contains highly focused photonic wheels beams expansion into vector spherical harmonics. It is needed because the Mie type scattering theory requires fields to be described in vector spherical harmonics base. The photonic wheel beam can be obtained by focusing two light beams which are circular right-handed and left-handed polarized. The result of interference at the lens focal point gives only a transverse angular momentum component of the beam. In this work, the same result can be obtained using the laser beam mode TEM01, which has two separate parts who are differently circular polarized, than it is focused and the result of focusing is a photonic wheel beam. The third part of the work contains photonic wheels beams interaction with spherical particles and meta-atoms made out of them. Angular momentum of the beam with and without a dielectric and metallic spherical particle at a focal point is calculated. The angular momentum remains transverse even with the particle being present. After that meta-atom of three spherical particles is constructed, the interest was to find such meta-atom configurations to be chirally optically responsive. The interaction of photonic wheel beams with such a meta-atom was calculated. During this work photonic wheel beam was successfully expanded into vector spherical harmonics, also the Mie type scattering theory was used to calculate the interaction of such beams with spherical particles and meta-atoms made of them. The chirally optically responsive meta-atom parameters were found and interaction of these meta-atoms with photonic wheel beam was calculated and visualized. |
