Ultrafast Laser Heating on Metal Films: Effects of Microvoids

2002 ◽  
Vol 16 (1) ◽  
pp. 30-35 ◽  
Author(s):  
D. Y. Tzou
Keyword(s):  
Laser Heating ◽  
Metal Films ◽  
Ultrafast Laser

Phase Transitions in the Picosecond Time Domain

1986 ◽  
Vol 77 ◽  
Author(s):  
Hani E. Elsayed-Ali ◽  
Gerard A. Mourou
Keyword(s):  
Laser Heating ◽  
Lattice Relaxation ◽  
Nonequilibrium State ◽  
Metal Films ◽  
Ultrafast Laser ◽  
Femtosecond Laser Irradiation ◽  
Lattice Temperature ◽  
Physical Processes ◽  
Time Resolved ◽  
Temperature Electron

ABSTRACTThe physical processes occurring during the initial stages of ultrafast laser heating of metals are described. Femtosecond laser irradiation is used to create nonequilibrium heating in metals. In such a nonequilibrium state, the electron temperature can be heated up to a few thousand degrees above the lattice temperature. Electron-lattice relaxation is time-resolved in copper and found to be 1 – 4 ps depending on the laser heating ffuence. The technique of time-resolved electron diffraction (a lattice structural and temperature probe) is described. Utilization of this technique for lattice temperature measurement of thin metal films is demonstrated.

Molecular Dynamics Simulation of Heat Conduction in Si Thin Films Induced by Ultrafast Laser Heating

2012 ◽  
Author(s):  
Yu Zou ◽  
Xiulan Huai ◽  
Fang Xin ◽  
Zhixiong Guo
Keyword(s):  
Molecular Dynamics ◽  
Heat Flux ◽  
Heat Conduction ◽  
Temperature Distribution ◽  
Laser Heating ◽  
Ultrafast Laser ◽  
Average Stress ◽  
Dynamics Simulation ◽  
Net Heat Flux ◽  
Si Films

Molecular dynamics simulations are carried out to study the thermal and mechanical phenomena of ultra-high heat flux conduction induced by ultrafast laser heating in thin Si films. Nanoscale Si films with various depths in heat flux direction are treated as a semi-infinite model for the study of ultrafast heat conduction. A distribution of internal heat source is applied to simulate the absorption of the laser energy in films and the induced temperature distribution. Stress distribution and the evolution of the displacement are calculated. Thermal waves are observed from the development of temperature distribution in the heat flux direction, though the average temperature of the simulated Si films increases monotonically. The average stress shows periodic oscillations. The time development of strain has the same trend as the average stress, and the net heat flux shows the same trend as the stress at different depths of the Si films in the direction of heat flux. This reveals a close relationship between stress and net heat flux in the Si films in the process of ultrafast laser heating.

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