Transportation of metal nanoparticles in a viscous medium by laser radiation
The aim of the work is theoretical investigation of the questions of transportation of spherical metal nanoparticles in a viscous medium with the help of the light pressure force of laser radiation with taking into account of weak heating of nanoparticles by laser radiation and the heat exchange with the surrounding environment. In the introduction the questions in which the problem of transportation of nanoparticles by laser radiation is the most relevant are listed and also some features of the laser radiation action on metal nanoparticles are considered. In the main part of the work, at first, the solutions of the equations describing the displacement of the spherical nanoparticle in a viscous medium under the action of the light pressure force of laser radiation are received and studied. It is shown that the predominant transport of nanoparticles occurs along the laser (the Gaussian) beam and the displacement of the nanoparticle is inversely proportional to the coefficient of viscosity of the medium. At second, the solutions for the temperature of a spherical metallic nanoparticle with its low heating by laser radiation and the temperature acquired by the environment when it is heated by nanoparticle are obtained and investigated. It is shown that the nanoparticle is heated up to a maximum temperature and the further action of laser radiation does not increase its temperature. The effective volume of the surrounding environment which is heated by the nanoparticle are estimated. The main results of the work are listed in the conclusion. Obtained in the present work new data on the problem of control of nanoparticle transport by light field can be used in the calculation of transportation of metal nanoparticles by laser radiation and also to estimate the optimal conditions for experimental investigations.