Multiple thresholds and many-atom dynamics in the cavity QED microlaser

C. Fang-Yen, C.C. Yu, A. Aljalal, R.R. Dasari, M.S. Feld, S. Ha, K. An
Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference  
This thesis describes a study of a cavity QED microlaser in which many atoms are present simultaneously and atom-cavity interaction is well-defined. The microlaser is found to display multiple thresholds analogous to first-order phase transitions of the cavity field. Hysteresis is observed as a function of atom-cavity detuning and number of atoms. Data is compared with a rate equation model and fully quantized treatment based on micromaser theory. Good agreement between theory and experiment is
more » ... found when the cavity is resonant with atoms of the most probable velocity, but long lifetimes of metastable states preclude the observation of true steady-state transition points. For nonzero atom-cavity detuning the microlaser displays broadenings and shifts which are not yet well-understood. Quantum trajectory simulations are performed to investigate many-atom and finite transit time effects in the microlaser. We show that over a wide range of parameters the many-atom microlaser scales with the single-atom theory, with a perturbation in the photon statistics due to cavity decay during the atom transit time. Thesis Supervisor: Michael S. Feld Title: Professor of Physics 3 4 Acknowledgments It is a pleasure to thank the many people who contributed directly or indirectly to this work. First I thank Michael Feld for his guidance and support during my time as a graduate student. His intuitive approach to physics and optimistic attitude will be an inspiration to me for years to come. I also appreciate the freedom he has given me as a graduate student to set the direction for my research. This thesis would not have been possible without Kyungwon An, who initiated the microlaser experiment as a graduate student. Kyungwon taught me a great deal about experimental physics during my early years at MIT. An equally large amount of credit for this thesis should go to Chung-Chieh Yu, who worked on the project for three years. His expertise in quantum optics and atomic beams helped move the project along faster than ever before. Ramachandra Dasari deserves thanks for many useful discussions, and for managing lab equipment and funding issues. From the beginning Ramachandra expressed confidence in me and my ability to eventually take on a leading role in the project. This is something I have appreciated very much. I enjoyed working with several other students in the laboratory. Abdulaziz Aljalal developed the optical velocity selection scheme and second-order correlation experiment. Bryndol Sones performed the absorption-induced bistability experiments. Alan Heins helped construct the dye laser locking system and the supersonic oven. Sangkeun Ha designed several of the electronic circuits and assisted with data collection. Professor John Thomas of Duke University deserves special thanks for helping us develop the supersonic beam oven that has proved critical to the success of these experiments. Thanks to Steve Smith of Coherent who often went out of his way to keep the laboratory equipped with working lasers.
doi:10.1109/qels.2002.1031011 fatcat:h7jis4gnrfafrmd4bttihqjkym