TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.12.6.193
TI  - Real-time ab initio description of the photon-echo mechanisms in extended systems: the case study of bulk GaAs
PY  - 2022/06/13
UR  - https://www.scipost.org/SciPostPhys.12.6.193
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 12
IS  - 6
SP  - 193
A1  - D'Alessandro, Marco
AU  - Sangalli, Davide
AB  - In this paper we present an ab initio real-time analysis of free polarization decay and photon echo in extended systems. As a prototype material, we study bulk GaAs driven by ultra-short laser pulses of 10 fs (energy spread of 0.4 eV), with frequency tuned in the continuum of the optical spectrum. We compute the electronic polarization P(t), and define a computational procedure to extract the echo signal in the dipole approximation. Results are obtained in both the low and high field regime, and compared with a two-levels system (TLS) model, with parameters extracted from the ab initio simulations. ab initio results are in optimal agreement with the TLS in the low-field case, whereas some differences are observed in the high-field regime where the multi-band nature of GaAs becomes relevant. In the high field regime we compute the pulse area, and look for fluences with pulse area close to {\pi}. We highlight that such fluences are well below the damage threshold of GaAs. However a unique value of the area cannot be defined, due to the strong dependence of the transition dipoles in the energy window excited by the laser pulse.
ER  -

@Article{10.21468/SciPostPhys.12.6.193,
	title={{Real-time ab initio description of the photon-echo mechanisms in extended systems: the case study of bulk GaAs}},
	author={Marco D'Alessandro and Davide Sangalli},
	journal={SciPost Phys.},
	volume={12},
	pages={193},
	year={2022},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.12.6.193},
	url={https://scipost.org/10.21468/SciPostPhys.12.6.193},
}