ИСТИНА

We present an approach for obtaining resonant silicon nanoparticles decorated with gold nanoparticles to enhance absorption in the transparency region of biological tissues. Highly selected spherical silicon nanoparticles with average diameters of 120 and 160 nm were prepared by femtosecond laser ablation of crystalline Silicon targets in water followed with centrifugation. These nanoparticles were used to form nanocomposite particles consisting of initial silicon cores and gold nanoparticles by using wet chemical synthesis. A twofold increase in the extinction of nanocomposite particles in the near-IR region was achieved compared to pure silicon nanospheres. An increase in extinction in the long-wavelength region with the deposition of gold NPs can be associated with the appearance of coupled plasmon-dielectric resonances. Numerical simulations of the optical absorption, scattering and spatial distribution of electric fields in an ensemble of pure silicon and composite nanoparticles dispersed in water are carried out. Finite difference modeling is in good agreement with the experimental results. The effect of Mie resonances in silicon nanoparticles and combined plasmon-dielectric resonances in composite ones for enhanced localized photoheating is demonstrated. An aqueous solution of silicon nanoparticles (0.05 g/l) with deposited gold was heated by 15 K when irradiated with a laser at a wavelength of 810 nm and an intensity of 200 mW. The obtained results are promising for use in biophotonics and photohyperthermia of biological tissues.