The use of lasers is ubiquitous in modern science and technology, with applications ranging from optical interferometers to compact disk players. This project investigates the physics of quantum dots that are coupled to microwave cavities. Quantum dots are nanoscale devices that can be used to trap single electrons. A microwave cavity consists of two 'mirrors' that trap a single photon of light for a relatively long period of time. The research team has shown that it may possible to create a new type of laser by flowing single electrons through a quantum dot that is coupled to a cavity. The research team is performing measurements to determine if single microwave photons can be generated with the device. In addition to training graduate and undergraduate students, the principal investigator will support a comprehensive outreach program. A 'quantum device' website is being constructed and new tutorials will be created to demonstrate basic concepts in classical mechanics.
The project aims to understand the dynamics of quantum dots that are coupled to a single microwave cavity. Single electron tunneling in this system results in photoemission and the statistics of the resulting light field is being studied. By pumping single electrons through a cavity coupled double quantum dot, the research team is attempting to create a deterministic single photon source that operates in the microwave regime. Photon detection aspects are being studied, by using one double quantum dot as a photon emitter and a second double quantum dot as a photon detector. The experiments are made possible by cutting-edge technological advances in quantum dot devices and quantum limited amplification. In the advanced phase of the program, the research team will couple multiple quantum dots to a single microwave cavity and search for collective effects. For example, do charge transitions in one double quantum dot couple to another quantum dot that is located ~ 1 cm away via the cavity field? Is it possible to observe collective enhancements in photon emission, such as Dicke superradiance? In addition to the technical effort, the research team will develop a 'Quantum Device Wiki' that introduces the basic aspects of quantum devices (single electron charging and Pauli blockade). The Wiki also supports several simulation packages that will be of use to the technical community. The principal investigator is creating short classical mechanics tutorials that will be posted on the internet for open access.
