Two-Temperature Model
Electron-phonon nonequilibrium thermalization
Parameters
Laser pulse energy
1.0
e-ph coupling g
0.50
Electron heat cap C_e
0.10
Lattice heat cap C_l
1.00
Pulse width (fs)
50
Fire Laser Pulse
Reset
T_electron
300
K
T_lattice
300
K
Two-temperature model
(Anisimov 1974): after ultrafast laser excitation, electrons thermalize rapidly (~100 fs) while the lattice heats slowly via electron-phonon coupling g:
C_e dT_e/dt = S(t) - g(T_e-T_l)
C_l dT_l/dt = g(T_e-T_l)
The electron temperature can reach tens of thousands of K while the lattice stays near room temperature — a strongly nonequilibrium state.