title: Optical phonon sidebands of electronic intersubband absorption in strongly polar semiconductor heterostructures.
abstract: We present the first evidence for a distinct optical phonon progression in the linear and nonlinear intersubband absorption spectra of electrons in a GaN/Al(0.8)Ga(0.2)N heterostructure. Femtosecond two-color pump-probe experiments in the midinfrared reveal spectral holes on different vibronic transitions separated by the LO-phonon frequency. These features wash out with a decay time of 80 fs due to spectral diffusion. The remaining nonlinear transmission changes decay with a time constant of 380 fs. All results observed are described by the independent boson model.
authors.affiliation: Max-Born-Institut fùr Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany.
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: K
authors.initials: K
authors.lastname: Reimann
authors.forename: M
authors.initials: M
authors.lastname: Woerner
authors.forename: T
authors.initials: T
authors.lastname: Elsaesser
authors.forename: D
authors.initials: D
authors.lastname: Hofstetter
authors.forename: J
authors.initials: J
authors.lastname: Hwang
authors.forename: W J
authors.initials: WJ
authors.lastname: Schaff
authors.forename: L F
authors.initials: LF
authors.lastname: Eastman