Nonlinear absorption,scattering, and extinction of laser radiation by two-layered spherical system-gold nanoparticle and vapor shell in water

Nonlinear absorption, scattering and extinction of laser radiation with wavelengths 532, 633 nm by spherical gold nanoparticles (NPs) with radii in the range of 5–100 nm placed in water and heated by laser radiation with formation and expansion of vapor nanoshells is theoretically investigated. Decrease of absorption, decrease and subsequent increase of scattering and extinction with increasing of shell radius beginning from the initial period of shell expansion is established. Optical indicatrixes and nonlinear behavior of scattered radiation are investigated including the examination of these characteristics during the adiabatic expansion of vapor shell. Formation of vapor nanoshells (bubbles) as a result of the action of short laser pulses on NPs placed in tissue was proposed for cutting of tissue.