CC BY
46LM-I-8
Assessment of the time-dependent density functional theory for investigating femtosecond laser energy absorption by metals
T. J.-Y. Derrien1, Y. Levy1, N.M. Bulgakova1
institute of Physics AS CR, HiLASE Centre, Za Radnici 828, 25241 Dolni Brezany, Czech Republic.
derrien@fzu. cz
Measuring and predicting the absorption of laser energy by crystalline materials is of high interest fo improving control in laser processing of solids [1]. Depending on the choice of laser parameters and of materials, a wide range of phenomena can affect the absorption dynamics of the intense light [1]. As a result, several kinds of theoretical descriptions are being developed to investigate this problem based on the Drude formalism, fi nite temperature DFT, combining DFT with two -temperature modeling, and time-dependent density functional theory ( TDDFT) [ 2-5]. Among the listed approaches, only the TDDFT enables to get insight into non -equilibrium dynamics of laser -excited electron subsystems in solids, both in semiconductors [ 6-8] and metals [ 5,9]. Using this technique, the possibility to study high intensit y regimes beyond the Kubo-Greenwood approximation was evidenced [9].
In this work, the TDDFT [10] was used to investigate the energy absorption of several metallic materials irradiated by ultrashort infrared and UV laser pulses. The energy absorbed and the electron current generated in the laser-irradiated metals were calculated as a function of time and for a wide range of laser intensities. The simulation results provide insights into the role of the fields induced by the oscillation of charges in the bulk of metals and allow to study the metal optical response at high intensities, beyond the usually employed approximations. A comparison of the obtained results with experimental data, which are available in literature, is provided.
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