Demonstrating the decoupling regime of the electron-phonon interaction in a quantum dot using chirped optical excitation
Kaldewey, T. and Lüker, S. and Kuhlmann, A.V. and Valentin, S.R. and Chauveau, J.-M. and Ludwig, A. and Wieck, A.D. and Reiter, D.E. and Kuhn, T. and Warburton, R.J.
PHYSICAL REVIEW B
Volume: 95 Pages:
Excitation of a semiconductor quantum dot with a chirped laser pulse allows excitons to be created by rapid adiabatic passage. In quantum dots this process can be greatly hindered by the coupling to phonons. Here we add a high chirp rate to ultrashort laser pulses and use these pulses to excite a single quantum dot. We demonstrate that we enter a regime where the exciton-phonon coupling is effective for small pulse areas, while for higher pulse areas a decoupling of the exciton from the phonons occurs. We thus discover a reappearance of rapid adiabatic passage, in analogy to the predicted reappearance of Rabi rotations at high pulse areas. The measured results are in good agreement with theoretical calculations. ©2017 American Physical Society.