Model for estimations of laser threshold fluencies for photothermal bubble generation around nanoparticles

Abstract

Theoretical investigation and estimations of the laser threshold fluencies are carried out for evaporation of water and bubble generation around of solid spherical nanoparticles by laser pulses. Simple analytical model has been developed for this purpose. The temporal dependences of nanoparticle temperature and energy conservation law are used for estimations of laser threshold fluencies. The dependences of the threshold fluencies on pulse durations, laser wavelengths, and nanoparticle radii are investigated and discussed. Comparison has been given some predicted values of the laser threshold fluencies for bubble generation in water around gold spherical nanoparticle with experimental data. The use of the fitting parameter (maximal nanoparticle temperature at the end of laser action) can provide the appropriate agreement of the results of developed model with experimental data. The estimation of maximal nanoparticle temperature can provide the analysis of realized processes under laser action on nanoparticles and necessary validation of experimental data. These model and results can be used for the estimations of the threshold fluencies for photothermal bubble generation by laser pulses around nanoparticles and for applications in various laser technologies, especially in laser nanomedicine.