Holographicaly dispersed liquid crystals in polymer matrices (HPDLC) are optical Bragg grating media with very large diffraction efficiency. We performed detailed analysis of the diffraction properties as a function of an applied voltage. We were first to measure the diffraction efficiency of the HPDLC gratings for neutrons and found that it is 100 times larger from any holographic medium probed till now. We also showed that orientational fluctuations of liquid crystals in HPDLCs exhibit a form of Bloch waves, which is a consequence of periodic modulation of the orientational viscosity.
COBISS.SI-ID: 1946468
We have presented the first consistent theoretical model describing the spatial modulation of the electric polarization that spontaneously appear in some phases of the bent-core molecules. We have shown that the instability is the consequence of the coupling between chirality and molecular tilt and is a fundamental property of such liquid crystals. The appearance of the modulated phases depend on the magnitude of the coupling constant. The structure of these phases was discovered a few years ago and until our model there was no theoretical explanation for their existence.
COBISS.SI-ID: 20912167
With combined optical tweezers with magnetic field we measured interactions between two colloids in a nematic LC. We have shown that the viscosity is almost independent of the inter-particle separation. External magnetic field was also used to create isotropic repulsive interaction between the beads in an isotropic suspension. The interaction at small inter-particle separations was weaker than the interaction between two parallel dipoles. An experiment proved that in two dimensions such soft potential leads to formation of a variety of phases, not obtained from the power-law potential.
COBISS.SI-ID: 2143076
By combining Dynamic Light Scattering (DLS) and Nuclear Magnetic Resonance (NMR) the dimensions of the guanosine aggregates in aqueous solutions were determined. Moreover, the coexistence of tetrameric and monomeric assemblies - for many years a matter of extensive debate - was finally proved. We also investigated the deposition of thin layers of guanosine onto mica and other solid substrates. Under suitable experimental conditions guanosine is adsorbed into long 1D nanostructures called the G4-wires that can reach up to 10 micrometers in length.
COBISS.SI-ID: 9783574
Using a model of optical and thermal transport as well as radiative emission, based on 3D digitized biopsy of port wine stain (PWS) lesions, we have shown that photothermal profiling with dual-wavelength excitation enables reliable determination of lesion characteristics relevant for guidance of therapy on individual patient basis. New algorithm for temperature profile reconstruction and an original approach to determination of the effective IR absorption have significantly improved the profiling accuracy. The results are highly relevant for advancement of dermatologic laser surgery.
COBISS.SI-ID: 22168615