This award supports an experimental research program that studies coherent photon-atom interactions in a coupled cavity-atom system consisting of multiple multi-level atoms interacting with one or two cavity modes and also with free-space laser fields. The experiments are carried out with laser-cooled rubidium atoms confined in an optical resonator. The prior work of the PI's group showed that the collective coupling of the cavity field and atoms can be used to produce the intra-cavity dark state and create cavity electromagnetically induced transparency. The PI's group also showed that the free-space laser field can be used to induce the destructive interference in the coupled cavity-atom system and control the quantum states of the cavity QED system. The planned experiments will use such interplay of the cavity QED and the quantum interference induced by the free-space laser fields to obtain large optical nonlinearities and to study light control light phenomena such as all-optical switching and large cross-phase modulation at ultra-low light intensities. The experiments will also be carried out in the cavity-atom system with a free-space, multi-frequency control light field that creates broadband electromagnetically induced transparency, which is useful for studies of a multichannel, broadband light memory. The funded research will advance knowledge of the fundamental physics of photon-atom interactions, lead to discoveries of new phenomena, and result in the development of coherent optical techniques for applications in quantum state manipulation, spectroscopic measurements, light-control-light photonic devices, and storage and conversion of quantum information. The research activities are carried out at Florida International University (a minority institute) and involve contributions from graduate and undergraduate students, particularly minority students. The research projects use advanced experimental methods and perform sophisticated experiments with advanced laser optical techniques and spectroscopic measurements, which offers research related education and training opportunities for the graduate and undergraduate students and enable them to develop scientific knowledge and technical skills in their pursuit of scientific and technological careers.