Influence of Interface Thermal Resistance on Relaxation Dynamics of Metal-Dielectric Nanocomposite Materials under Ultrafast Pulse Laser Excitation

Abstract

Nanocomposite materials, including noble metal nanoparticles embedded in a dielectric host medium, are interesting because of their optical properties linked to surface plasmon resonance phenomena. For studding of nonlinear optical properties and/or energy transfer process, these materials may be excited by ultrashort pulse laser with a temporal width varying from some femtoseconds to some hundreds of picoseconds. Following of absorption of light energy by metal-dielectric nanocomposite material, metal nanoparticles are heated. Then, the thermal energy is transferred to the host medium through particle-dielectric interface. On the one hand, nonlinear optical properties of such materials depend on their thermal responses to laser pulse, and on the other hand different parameters, such as pulse laser and medium thermodynamic characterizes, govern on the thermal responses of medium to laser pulse. Here, influence of thermal resistance at particle-surrounding medium interface on thermal response of such material under ultrashort pulse laser excitation is investigated. For this, we used three temperature model based on energy exchange between different bodies of medium. The results show that the interface thermal resistance plays a crucial role on nanoparticle cooling dynamics, so that the relaxation characterized time increases by increasing of interface thermal resistance.