John D. Joannopoulos

Prof. Joannopoulos' research efforts have been in theoretical condensed matter physics, and he is responsible for the development of numerous theoretical methods to enable tractable and accurate calculations of elementary excitations in complex many-particle systems. In particular, his interests have spanned a wide range of topics including the electronic, vibrational, and optical structure of crystalline and amorphous bulk solids, their surfaces, interfaces, and defects; localization in disordered systems; phase transitions and critical phenomena; and, over the past two decades, the theory of lightwave phenomena in photonic crystals. Photonic crystals are periodic dielectric structures that have a band gap that forbids propagation of a certain frequency range of light. This and other properties of these systems enable one to control light with amazing facility and produce effects that are impossible with conventional materials, including reverse Doppler shifts, anomalous Cerenkov radiation, negative refraction and subwavelength imaging, bandwidth-narrowing without losses, magnetic-dipole radiation from non-magnetic photonic crystals, and one-way lightwave-guiding with complete immunity to disorder and obstacles.