Simulation of the optical properties of surface nanostructures for photoacoustic converters

A computer model has been developed and a theoretical study has been performed for nanostructures in the form of a twodimensional monolayer of nanoparticles of noble metals on an optical fibre end face. The parameters of nanostructure-based photoacoustic converters are chosen for different environments in order to provide a high light absorption coefficient, which, in turn, provides a maximally high conversion efficiency for ultrasound generation. It is established that efficient photoacoustic conversion can be implemented in a surface nanostructure composed of spherical gold nanoparticles, located on an optical fibre end face in water, in wide ranges of the nanostructure microscopic parameters. It is shown that the backscattering coefficient also turns out large in the case of resonance absorption; for this reason, one must provide optical isolation of a laser in use when designing photoacoustic generators.