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Differential transient absorption spectra have been studied for planar densely packed Ag/Na 3 AlF 6 nanostructures under ultrashort laser pulse excitation. The nanostructures were fabricated by sequential thermal evaporation of cryolite (Na 3 AlF 6 ) and silver in vacuo onto glass and quartz substrates. A nonmonotonic variation in relaxation times of induced changes in a surface plasmon resonance band was observed with an increase in the metal surface density that resulted in nanoparticle size growth and structural modification of the densely packed layer. The tendency of the relaxation times to vary nonmonotonically is explained by both features of intrinsic size effects and electron-tunneling processes in plasmonic densely packed nanostructures of various topologies. Keywords: ultrashort laser pulses, dynamics of electron excitations, densely packed nanostructures, surface plasmon resonance.Introduction. Metal-containing nanocomposites that incorporate nanoparticles of noble metals exhibit unique optical and opto-electronic properties. Localized resonances of surface plasmon absorption are to a large extent responsible for these properties and arise as the result of collective vibrations of conductivity electrons in the metal nanoparticles. Such nanostructures are labeled plasmonic. Excitation of plasmonic nanocomposites by ultrashort light pulses creates a highly non-equilibrium state of the electrons in the nanoparticles. This is reflected in the spectral properties of the nanostructures. The rapid evolution of the non-equilibrium state and; therefore, the spectral characteristics of the nanocomposite with time, follow laws that are determined by both the properties of the metal nanoparticles and their environment.Studies of the dynamics of electron excitations in plasmonic nanostructures are important for solving practical problems related to the fabrication of rapid-acting fully optical modulating devices and switches and the development of methods for diagnosing nanostructured materials. The electron dynamics in metal nanoparticles differ from those of the bulk material because of their limited size. The relaxation dynamics of electron excitations in plasmonic nanostructures were studied until now mainly for dilute colloids and nanocomosites characterized by a small bulk concentration of plasmonic particles. In this instance the dynamics were determined mainly by the properties of the individual nanoparticles and could depend on both the particle material and size and shape [1][2][3][4][5]. Thus, a significant decrease of the plasmon decay rate in gold nanocylinders as compared with spherical particles was observed [4]. An analogous effect was found for metal nanoshells [5].Dense packing and partial spatial ordering of metal nanoparticles provide additional possibilities for controlling the optical characteristics of plasmonic nanostructures [6,7]. In these instances effects of a collective nature become significant. It can be expected that such systems with densely packed plasmonic nanoparticles will also...

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Nanoarrays of Co nanorods were formed by means of electrochemical deposition in the nanoporous SiO2/ n-Si templates. Structure and magnetic properties at room temperatures were studied by means of atomic force and scanning electron microscopies, vibrating sample magnetometry. The presence of perpendicular magnetic anisotropy component at room temperature makes Co nanorods in the nanoporous SiO2/n-Si templates promising for nanoelectronic devices and biomedical applications.

Nanostructured thin films on a silicon substrate have been obtained by the method of high-frequency repetitively pulsed (f ~ 10—15 кГц) laser action with a wavelength of 1.064 μm and a power density q = 54 MW/cm2 on La0.4Ba0.6CoO3 ceramics at a pressure in the vacuum chamber p = 2.2 Pa. The morphology of the obtained films was studied using atomic force microscopy. The features of the transmission spectra in the visible, near, and mid-IR regions are revealed. An analysis of the electrical properties of the La0.4Ba0.6CoO3 structure was carried out.