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Excitons in Semiconductor Quantum Wells Studied Using Two-Dimensional Coherent Spectroscopy

Event Details

Event Dates: 

Monday, August 10, 2015 - 3:00pm

Seminar Location: 

  • JILA 10th Floor - Sunrise Room

Speaker Name(s): 

Rohan Singh

Speaker Affiliation(s): 

Seminar Type/Subject

Scientific Seminar Type: 

  • JILA Thesis Defense

Event Details & Abstract: 

Correlated electron-hole pairs, or excitons, in semiconductor nanostructures have been studied over the past few decades. The optical response of excitons is complicated due to inhomogeneous broadening, presence of multiple states, and exciton-exciton interactions. In this work we bring new perspectives to exciton physics in semiconductor quantum wells (QWs) through two-dimensional coherent spectroscopy. We have studied the polarization-dependent exciton dephasing rate in low-symmetry structures, which depends on the crystal-axis-dependent absorption coefficient. Our experiments on the spectral diffusion of excitons highlight the limitations of previously used models at low sample temperatures. Finally, we have developed an intuitive and simple model to include exciton-exciton interactions by treating excitons as interacting bosons. We quantify these interactions using a numerical fitting procedure.