This project will develop the theory of a new and technologically important type of light source that promises to generate the purest color ever produced, surpassing the most stable lasers built to date by orders of magnitude. Such a light source would operate in a completely novel regime, utilizing special atoms that have extraordinarily narrow transitions. The specific goal is to unify the theory of this new device with that of the laser and to correctly describe the intermediate regime.
This project could have important technological implications beyond the intellectual interest. Lasers have had substantial impact on society in the past fifty years since their discovery. The plan here is to expand the basic understanding of the laser to encompass a much broader reach, and it could eventually lead to important applications, technological developments, and devices, especially in the field of atomic clocks and precision measurements. The program will involve the education and training of undergraduates, graduates, and postdoctoral researchers.
In this research program, we have developed a theoretical understanding of a new kind of "superradiant" laser that promises to possess an extremely pure color. There are many applications of such a device with extreme spectral purity, to both the development of basic science and the understanding of fundamental physics as well as to specific technological challenges that are overcome by the ability to make precision measurements. We have shown in this work that there is a smooth crossover with an adjustable parameter that links this new kind of revolutionary device with conventional lasers of the type that is familiar to everyday life. The adjustable parameter is the dimensionless ratio of the bandwidth of the pump source that provides the energy to the laser to the bandwidth of the optical cavity in which the photons in the laser are stored. Our accomplishments are on several alternative implementations of this novel device. The first system we considered uses the alkaline-earth atom strontium-87 and was motivated by the strontium-87 optical lattice clock used in the laboratory of Professor Jun Ye at JILA. This is one of the state-of-the-art clocks in the world. When combined with an extremely stable laser of the kind that we have proposed, this clock would be the key component of the next generation of precision metrology systems. We considered a number of other potential systems including a Raman system where the coupling was not fixed by nature, but was tunable. This work was done in collaboration with James Thompson at JILA, and led to a Nature paper that was published. Along with this publication, our research has led to a number of papers in peer reviewed Physical Review journals, and to conference presentations at international science symposia. We have supported a graduate student conducting PhD research on this project and an undergraduate who complete her honors Thesis and is now working towards her PhD in graduate school.
