Theoretical investigation of the distributions of laser radiation intensities inside spherical gold nanoparticles
with radiuses in the range 5-100 nm during laser irradiation for wavelengths 400, 532, 800 nm was carried out.
Distributions of laser intensity are nonhomogeneous for some ranges of nanoparticle sizes and values of laser
wavelengths. These results can be applied for explanation of some experimental data of laser-induced
fragmentation, evaporation and formation of nanonetworks as a result of laser action on nanoparticles and for
laser technologies of nanoparticles.
Photothermal-based effects in and around gold nanoparticles under action of short (nano, pico- and femtosecond)
laser pulses are analyzed with focus on photoacoustic effects due to the thermal expansion of nanoparticles and
liquid around them, thermal protein denaturation, explosive liquid vaporization, melting and evaporation of
nanoparticle, optical breakdown initiated by nanoparticles and accompanied to shock waves and explosion
(fragmentation) of gold nanoparticles. Characteristic parameters for these processes such as the temperature and
laser intensity thresholds are summarized to provide basis for comparison of different mechanisms of selective
nanophotothermolysis of different targets (e.g., cancer cells, bacteria, viruses, fungi, and helminths).
Computer calculation of optical properties of core-shell metal nanoparticles was made for some laser
wavelengths. Efficiency factors of absorption, scattering and extinction by spherical core-shell gold-silver and
silver-gold nanoparticles of the radiuses in the range 5-100 nm and for laser wavelengths 400, 532 and 800 nm
were calculated. Analysis of influence of optical parameters of metals, radiuses of core and thicknesses of shell
on optical properties of nanoparticles was made.
The model of corneal biotissue layers and their values of optical parameters are presented. The model of the processes involved in laser thermal keratoplasty of eye biotissues is proposed, and the results of computer modeling are presented. Characteristics of optical and thermal processes and the influence of parameters of radiation and biotissues on the results of laser action are studied. The results of numerical simulations demonstrate the possibility of heating of the region in corneal stroma by a converging beam of laser radiation with a sufficient parameters.
Energy absorption, heat transfer, thermodenaturation under the action of laser radiation pulse on pigmented spherical granules in heterogeneous laminated biotissues are investigated on the base of mathematical simulation. The possibility of selective interaction between short radiation pulses and pigmented retina biotissues is noted which results in the formation of thermodenaturation microregions inside and near the melanosomes. These denaturation microregions can originate in the eye biotissue under laser radiation intensities less than about 2 - 4 times the threshold ones determined ophthalmoscopically. These microdamages can appear without being detected by the standard ophthalmoscopical methods.
This paper presents the results of theoretical and experimental investigation of lithotripsy processes by means of Ruby laser. The possibility of obtaining smooth microsecond pulse by two-photon absorption and negative feedback techniques is investigated. The methods of increasing of lithotripsy processes efficiency had been considered.
Energy absorption, heat transfer, thermodenaturation, explosive vaporization and optical breakdown under the action of laser radiation pulse on pigmented melanosomes in heterogeneous laminated biotissues are investigated theoretically.
Energy absorption, heat transfer, thermodenaturation and vapor blanket formation under the action of laser radiation pulse on pigmented spherical granules in heterogeneous laminated biotissues are investigated theoretically.
Energy absorption, heat transfer, thermodenaturation and vapor blanket formation, under the action of laser radiation pulse on pigmented spherical granules in heterogeneous laminated biotissues are investigated theoretically.
The possibility for selective thermodenaturation (coagulation) of pigment epithelium layer by an appropriate choice of parameters of short laser pulses, while the functioning of neighboring layers is preserved, is shown on the basis of mathematical simulation.
In the present paper, by using computer simulation investigation of thermal interaction of a laser radiation beam with different wavelengths with intraocular hemorrhages and nonpigmented tumors, which leads to thermal denaturation (coagulation) of blood and tissues is performed.
The problem of selective laser coagulation, i.e. optimal laser control over dimensions, shapes, and location of the region of tissue coagulation (thermodenaturation) by an appropriate choice of parameters of the active laser radiation is considered.
Energy absorption, heat transfer and temperature distributions during the interaction of laser radiation pulses with pigmented spherical and spheroidal granules in heterogeneous laminated biotissues are investigated on the basis of mathematical modeling.
The computer simulation of light propagation in homogeneous and heterogeneous biotissues accounting for absorption and scattering radiation energy by pigmented granules and diffraction is made.
Energy absorption, heat transfer and thermodenaturation occurring during the interaction of laser radiation pulses with pigmented spherical and spheroidal granules in heterogeneous biotissues are investigated on the base of mathematical simulation. The possibility of selective interaction between short radiation pulses and pigmented biotissues is shown which results in the formation of thermodenaturation microregions inside and near the pigmented granules.
The model is elaborated and results of numerical computations of variation of radiation reflection factor for laminated eye biotissues during their laser coagulation are considered. Comparison of certain simulation results and experimental data is performed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.