## Department of Physics

### Department News

### Quadri Thesis Presentation

**Nov 22, 2013**

**THESIS PRESENATION
Speaker: Adetola Quadri, graduate student
Date: Tuesday, December 3, 2013
Time: 3:30 PM
Room: Currens Hall 336
Optical Pulse Propagation: Macroscopic and Microscopic
Abstract: **

Both a macroscopic and microscopic approach for describing the evolution of light pulses propagating through a dispersive nonlinear medium are presented. In the macroscopic approach, the bulk properties of the medium are considered in the nonlinear Schrodinger equation for wave propagation, which is solved in the slow-varying envelope approximation using a high-order Split-Step Fourier scheme. This is used to demonstrate the effects of group velocity dispersion, self-phase modulation, and soliton propagation in a medium. It is demonstrated that the same effects can be generated by an alternative approach given in the microscopic regime which models the medium of a set of multi-level atoms existing in well-defined energy levels using the density matrix formalism. In carrying out this microscopic approach, a code is developed which automates the generation of the optical Bloch equations, which are a set of density-matrix equations of motion for an atomic system in the presence of light fields. The resulting equations are coupled with the light field equations and integrated numerically in order to define the spatial and temporal properties of propagating optical pulses in a medium towards explaining even more interesting physical phenomena.

**About the speaker:**

Adetola Quadri is a graduate student in the Western Illinois University Department of Physics working under Dr. Kishor Kapale. Upon successful completion of his thesis, he stands to graduate in December 2013.