Coherent Two-Dimensional Optical Spectroscopy

Warren S. Warren, Ahmed H. Zewail

Jakub Dostál

Gaël Nardin, Travis M. Autry, Galan Moody +3 more

We review our recent work on multi-dimensional coherent optical spectroscopy (MDCS) of semiconductor nanostructures. Two approaches, appropriate for the study of semiconductor materials, are presented and compared. A first method is based on a non-collinear geometry, where the Four-Wave-Mixing (FWM) signal is detected in the form of a radiated optical field. This approach works for samples with translational symmetry, such as Quantum Wells (QWs) or large and dense ensembles of Quantum Dots (QDs). A second method detects the FWM in the form of a photocurrent in a collinear geometry. This second approach extends the horizon of MDCS to sub-diffraction nanostructures, such as single QDs, nanowires, or nanotubes, and small ensembles thereof. Examples of experimental results obtained on semiconductor QW structures are given for each method. In particular, it is shown how MDCS can assess coupling between excitons confined in separated QWs.

C.N. Borca, Tianhao Zhang, S.T. Cundiff

Two-dimensional Fourier-transform optical spectroscopy is demonstrated on GaAs quantum-wells. The signal is measured phase coherently with respect to the evolution time, enabling Fourier analysis. Coupling between heavy and light hole excitons yields cross-peaks.

Hebin Li, Steven T. Cundiff

Wolfgang Demtröder