CPM Seminar

An Excitonic Approach to the Intraband THz Response of Semiconductor Nanostructures

Marc Dignam

Department of Physics, Engineering Physics and Astronomy
Queen's University

Considerable effort has been devoted in recent years to developing an accurate and computationally-viable theoretical treatment of the optical and THz response of semiconductor nanostructures that are excited by ultrashort optical pulses. Although most approaches, such as the semiconductor Bloch equation, employ an electron-hole basis, we have developed an excitonic approach that has significant advantages in many situations. By employing an excitonic basis and truncating the dynamic equations via factorization, we are able to calculate the nonlinear optical response to infinite order in the optical field while retaining crucial intra-excitonic electron-hole correlations. Our approach includes the exchange interaction between excitons, the effects of the Pauli exclusion principle for the excitons (which are composite Bosons), and the dipole-dipole interactions between excitons. In this talk I will discuss the application of our approach to THz emission and THz absorption of semiconductor quantum wells and biased semiconductor superlattices and will compare our theoretical results with experiments where possible.