An all-optical switch based on a one-dimensional layered structure with defocusing nonlinearity

The feasibility of an optical switch of femtosecond range controlled by a femtosecond light pulse acting on a nonlinear one-dimensional photonic crystal (a layered one-dimensional periodic structure) is demonstrated by computer simulation. The crystal comprises linear and weakly defocusing layers. It is shown that switching occurs when the peak intensity of the initial pulse exceeds a certain threshold value due to the dependence of the transmission-reflection bands of the photonic crystal on the nonlinearity of the medium.     

Radical Processes in the Low-Temperature Radiolysis of Liposome Dispersions

Processes occurring with the participation of radiolytic radicals in the low-temperature radiolysis of aqueous liposome dispersions were studied. The initial radiation-chemical yields of the resulting radicals were determined, and the transformations of these radicals upon freezing-out the systems were examined. It was found that ionol (2,6-di-tert-butyl-4-methylphenol) introduced into the lipid bilayer of liposomes is an effective scavenger of radiolytic species formed in a frozen (77 K) dispersion upon irradiation.     

High sensitive electrolytical conductivity measurements of irradiated polymer films of 1μm thickness measured by a modified experimental set-up

The interaction of heavy ions with solids produces a narrow radial core of primary damage. The actual nature of the damage and the mechanism of its formation is not yet fully understood.

The technique of the electrochemical etching of irradiated samples is an useful method to investigate these structures of the track cores. The transversale etching rate as a function of the radius, derived from the time-dependence of the radius of the etching pore, can be interpreted as the corresponding magnitude of the degree of the damage within the track core.

To carry through measurements of smallest radii of etching pores, their very high electric resistance respectively, a sophisticated experimental set-up is required.

An advanced set-up is performed, which enables, by application of a combined d.c.-a.c.-method, to measure the resistance of the sample during the whole etching process, associated with the origin of pore and its growth up to radii of 10 nm and more.