Faculté des sciences

Ultrafast hole burning in intersubband absorption lines of GaN/AlN superlattices

Wang, Z. ; Reimann, K. ; Woerner, M. ; Elsaesser, T. ; Hofstetter, Daniel ; Baumann, E. ; Giorgetta, Fabrizio R. ; Wu, H. ; Schaff, W. J. ; Eastman, L. F.

In: Applied Physics Letters, 2006, vol. 89, no. 151103, p. 1-3

The authors present evidence for a distinct optical phonon progression in the nonlinear intersubband absorption spectra of electrons in a GaN/AlN superlattice. Femtosecond two-color pump-probe experiments in the near infrared show spectral holes separated by the longitudinal optical (LO) phonon frequency and a homogeneous line broadening of approximately 50 meV. The nonlinear bleaching signal... Plus

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    Summary
    The authors present evidence for a distinct optical phonon progression in the nonlinear intersubband absorption spectra of electrons in a GaN/AlN superlattice. Femtosecond two-color pump-probe experiments in the near infrared show spectral holes separated by the longitudinal optical (LO) phonon frequency and a homogeneous line broadening of approximately 50 meV. The nonlinear bleaching signal decays with a time constant of 160 fs due to intersubband scattering of delocalized electrons, followed by a weak picosecond component attributed to the relaxation of electrons from longer-lived localized states.