Theoretical & Computational Physics
Top: Measured (left) and calculated (right) energy loss probability of electrons passing nearby the gold crescent particle (inset). Bottom: Measured (left) and calculated (middle) spatial distribution of the energy loss probability for a longitudinal dipole plasmon resonance together with the calculated induced electric field (right).
Vlastimil Křápek's primary area of interest is a theoretical and numeric modeling of various nanoscale systems, including metallic nanoparticles, semiconductor quantum dots, quantum dot molecules, and their complexes. He studied the interrelation between the structural, electronic, and optical properties of quantum dots as well as their tunability by external effects (electric, magnetic, and strain field). In collaboration with experimentalists he pursues technologically important goals to push the emission of InAs quantum dots to the infrared telecommunication wavelengths or to lower the excitonic fine structure splitting below the natural linewidth. Recently he turned his attention to the metallic particles hosting localized surface plasmon resonances. He is involved in the modeling of electron energy loss spectroscopy of plasmonic nanoparticles and interested in coupling of the plasmonic particles with quantum dots, focusing on the enhancement of their photoluminescence rate (Purcell effect). He coauthored 28 scientific papers to which over 200 references were made.
Fig.: Reflectivity profile of the forbidden symmetric (001) reflection on the Si(001) thick crystal. FDT = Forbidden Darwin table.
Petr Dub is involved in the theoretical description of interaction of light with solid matter. He started with applications of the group theory and Ewald's theory of diffraction in crystallography (collaboration with Otto Litzmann, Masaryk University). Then he switched to theoretical problems of solid state physics and electromagnetic field at surfaces and interfaces. During last several years he has broadened his focus also to plasmonics using both classical theory of fields and quantum mechanics.
Fig.: Scattered electric and magnetic fields (normalized to the incident electromagnetic wave) in the vicinity of a gold nanorod. The nanorod is depicted by the gray rectangle. The maps of amplitudes of near-field components calculated by developed analytical model and by FDTD simulations are shown in (a) and (b), respectively.
Radek Kalousek is currently mainly concentrated on calculations of optical properties of metallic nanostructures. During his PhD study he was focused on description of forces between the tip and the sample in atomic force microscopy (AFM) and processes taking part during the formation of AFM images. Afterwards his research continued with investigation of the diffusion of adatoms on surfaces [Co on Pt(111) (collaboration with M. Schmid, TU Wien), Ge on Ge(110) during nanowire growth (collaboration with M. Kolíbal)] and formation of water meniscus between the tip and sample surface during local anodic oxidation using conducting AFM tip (collaboration with M. Bartošík). He is also involved in solving other problems of theoretical physics concerning nanotechnology, i.e. theory of elasticity (AFM cantilever deformations and vibrations, mechanical properties of piezoceramics in slip-stick actuators, mechanical stress in deformed graphene); electrodynamics (optical properties of grainy dielectric materials); thermodynamics (heat spreading from illuminated nanostructures on substrates); magnetism: (trajectory of magnetic vortices moving in external magnetic field, magnetic damping system for reduction of unwanted mechanical vibrations); fluid mechanics (gases and liquids in nanocapillaries).