Computer modeling of optical properties of gold ellipsoidal nanoparticles at laser radiation wavelengths

Abstract

Processes of laser interaction with metal (gold) nanoparticles are of great interest for laser applications in nanotechnology, engineering, and medicine. Optical properties of nanoparticles determine photophysical and photochemical processes during laser treatment. Computer calculation of efficiency factors of absorption, scattering and extinction of radiation by ellipsoidal gold nanoparticles (two-dimensional ellipsoids of revolution) with small semiaxes in the range 5-100 nm, for some values of aspect ratio and angle of orientation of ellipsoid with respect to direction of laser radiation propagation and for some laser wavelengths is performed. The estimation of absorbed and scattered laser radiation energy by gold ellipsoidal nanoparticles, their maximal temperatures and comparison with experimental data is made. Efficiency factor of absorption for the prolate Au ellipsoid embedded into water versus the ellipsoid small semiaxis r b

Photothermal and accompanied phenomena of selective nanophotothermolysis with gold nanoparticles and laser pulses

“…In particular, we choose radius of nanoparticle r 0 = 30 nm, because GNs with this r 0 has maximal value of absorption efficiency (value of K ab ) for laser wavelengths in the range 300 -600 nm [8,9]. Besides, a minimal heat losses from GN with this size occurs for laser pulse duration t p < 10 −9 s (see below and Fig.…”

“…respectively and a spherical GN with radius of r 0 = 30 nm and initial temperature T ∞ = 310 K. Calculation of intensity I for concrete value of laser wavelength λ is carried out by using value of K ab (r o , λ) [8,9]. In particular, we choose radius of nanoparticle r 0 = 30 nm, because GNs with this r 0 has maximal value of absorption efficiency (value of K ab ) for laser wavelengths in the range 300 -600 nm [8,9].…”

Thermooptical comparison of different approaches and lasers for laser treatment of intraocular tumors

“…In this paper it were used the methods of theoretical analysis and computer modelling. Nowadays computer modelling is very effective and reliable method in investigations and allows thorough examination of the process characteristics and mechanisms of laser-tissue interaction, allows to accomplish a detailed treatment (time and space distributions) of some characteristics, which specify by the process of action and cannot be obtained using experimental methods [6,7].…”

Multifunctional theranostic gold nanoparticles for targeted CT imaging and photothermal therapy

“…Heat is then produced in the sample through the nonradiative de‐excitation of the electrons from the upper state back to the ground state. Detailed calculations concerning the time scales and heat generation involved in the photothermal process have been previously reported in various works . In order to ensure effective nanoparticle‐mediated photothermal therapy, the nanoparticles should be: small in size (about 100 nm or less in diameter) ; biologically compatible; and have no serious toxicity.…”