Method of Modeling Optoacoustic Signals in Composites Transparent Matrix – Metal Nanoparticles

Resumo

Method of modeling optoacoustic signals initiated by a laser pulse in composites transparent matrix – metal nanoparticles taking into account melting processes has been developed and tested. The method consists in calculating the function of pressure sources depending on time and coordinate and its convolution with the Green’s function of the one-dimensional wave equation. Testing has been performed for composites of pentaerythritol tetranitrate with 50 nm radius aluminum nanoparticles that are important for practical applications. The melting is characterized by an increase in the specific volume and leads to an increase in the amplitude of the maximum of the source function and the appearance of the area of its negative values. The dependences have been calculated of the effective growth constant of the optoacoustic signal and its amplitude on the pulse energy density that must be taken into account in this method. The results are important for the development of methods of nondestructive testing and prediction of functioning of photonic devices and optical detonators containing nanoparticles.