Lasers have long played an important role in our modern society and have recently celebrated its 50th birthday. The most prominent application of the laser is within communications, indeed the internet as we know it today would not be possible without the laser. Much of the success of the laser is owed to the constant miniaturization of semiconductor devices that have occurred over the last decades, enabling the use of lasers in previously unimaginable places.

The ultimate size limit of the laser is set by the size of the optical cavity comprising the laser, which cannot be smaller than approximately one wavelength of light. In the optical regime such cavities can be created in so-called photonic crystal cavities (see figure), where multiple reflections confine light to a very small area, creating a nanolaser. The active medium in these structures is made up of semiconductor quantum dots (QDs), that in many aspects behave very similar to ordinary atoms for which reason they are often referred to as artificial atoms (red pyramids in the figure).

In this project we will construct a quantum mechanical model of a nanolaser including several QDs as the active medium, and we examine the model both by an analytical and a numerical approach, e.g. using Matlab. We will explore the fascinating physics of the quantum realm and hopefully point out directions enabling actual devices. A specific goal of the project is to investigate the effects arising when the QDs are not identical, e.g. the transition energy might vary from QD to QD, which has not yet been examined. Come and see us if you are interested in hearing more about the project.

A basic knowledge of differential equation systems is required (e.g. from MAT 1), but the project may be approached even without any previous knowledge of quantum mechanics.