Mark Steger

Research

"ENHANCING MICROCAVITY POLARITONS FOR TECHNOLOGICAL APPLICATIONS" 
Microcavity exciton-polaritons, semiconductor quasiparticles that are a unique mixture of light and matter, are routinely used to study quantum many-body phenomena. Due to the light mass of the polariton,  10^-4 times the bare electron mass, polaritons manifest noticeable quantum effects even at room temperature. 
 
As solid state systems, microcavity polaritons are generally robust and compatible with current semiconductor technology. Microcavity chips could be integrated into electronic or optical circuits. I present a demonstration of microcavity polaritons as an all-optical transistor, where the strong nonlinearity of the system leads to a change in the reflectivity for a signal light-ray from high to low. I also discuss the promise of using strongly coupled microcavities as low-threshold polariton lasers, which could replace traditional lasers in some cases.
 
The last two decades have seen great strides in the material systems used in microcavities, even demonstrating strong coupling at room temperature. GaN, CdZnSe, organic semiconductors and more recently, MoS2 have supported strong coupling at ambient conditions. This makes technological applications more promising. I present our current progress in this fi 
eld. Also, the general quality of microcavities has advanced steadily over this time. I demonstrate that our long-lifetime polaritons persist for an order of magnitude longer than in similar samples. This opens up new regimes of study and technological application as these particles thermalize better and carry quantum coherence over macroscopic distances.

Dissertation

Degree

PhD

Graduate Advisor

David W Snoke