title: Two-dimensional terahertz correlation spectra of electronic excitations in semiconductor quantum wells.
abstract: We discuss a novel approach for nonlinear two-dimensional (2D) spectroscopy in the terahertz (THz) frequency range which is based on a collinear interaction geometry of a sequence of THz pulses with the sample. The nonlinear polarization is determined by a phase-resolved measurement of the electric field transmitted through the sample as a function of the delay τ between two phase-locked pulses and the "real" time t. The information provided by a single 2D scan along the τ and t axes is equivalent to that from a noncollinear photon-echo setup equipped with four local oscillators, each interacting with a different diffracted order. We address basic concepts of collinear 2D THz spectroscopy, in particular data analysis and phasing issues. Different rephasing and nonrephasing contributions to the third-order response are separated and 2D correlation spectra derived. As a prototype application, 2D correlation spectra of intersubband excitations of electrons in semiconductor quantum wells are presented.
authors.affiliation: Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Kuehn
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: R
authors.initials: R
authors.lastname: Hey
mesh_terms: D004583:Electrons; D011789:Quantum Theory; D012666:Semiconductors; D055068:Terahertz Spectroscopy / Q000295:instrumentation / Q000379:methods