Associate Professor, Department of Physics, Engineering Physics and Astronomy Associate Professor, Department of Physics, Engineering Physics and Astronomy Queen’s University Stirling Hall Room 371 Tel: (613) 533-6804 E-mail: dig...@physics.queensu.ca Quantum Optics in Photonic Crystals It is well known that the spontaneous emission of atoms, molecules, and quantum dots can be drastically affected by the environment in which they are placed. For example, the rate of spontaneous emission of an atom in vacuum will be very different from that of an atom in a small metallic cavity with dimensions on the order of the wavelength of the emitted radiation. Similarly, if an atom is located within the bandgap of a photonic crystal -- i.e. in the frequency range where there are no propagating electromagnetic modes in the structure – then the spontaneous emission can be completely suppressed. Conversely, the rate of spontaneous emission can be greatly enhanced if the atom is placed at the location of a defect in the photonic crystal, where the mode density is very high. This last effect is called the Purcell effect. We are currently researching the interesting dynamics of spontaneous emission in photonic crystals with multiple, coupled-cavity defect states [5,7,9,11,12,14,15]. We use a projected Green tensor approach to calculate the local density of states and spontaneous emission dynamics. We have found that the radiation dynamics can be very interesting in such structures. In particular, the spontaneous emission rate can be either enhanced or diminished due to quantum-path interference effects in the structure. This is demonstrated in the plot to the left, where we plot the local density of states for a double-cavity structure showing a large peak in the defect near x=-2 but a dip in the defect near x=+3. This approach makes it much easier to understand the basic physics of multiple-defect structures and has possible implications for quantum-computing applications of photonic crystals. More recently [9], we have been examining quantum optics in photonic crystal waveguides in the strong coupling limit. Until recently, such calculations were prohibitive due to the complexity of the system. However our new projective techniques make a wide variety of complex structure amenable to investigation. These results are leading to a better understanding of the role of quantum path interference in photonic crystals. Queen’s University Stirling Hall Room 371 Tel: (613) 533-6804 E-mail: dig...@physics.queensu.ca RESEARCH INTERESTS All of my research lies in the area of theoretical condensed-matter physics and nonlinear and quantum optics. This work ranges from pure to applied physics and often involves collaboration with experimentalists. The following is a brief overview of some of my current research interests. Quantum Optics in Photonic Crystals It is well known that the spontaneous emission of atoms, molecules, and quantum dots can be drastically affected by the environment in which they are placed. For example, the rate of spontaneous emission of an atom in vacuum will be very different from that of an atom in a small metallic cavity with dimensions on the order of the wavelength of the emitted radiation. Similarly, if an atom is located within the bandgap of a photonic crystal -- i.e. in the frequency range where there are no propagating electromagnetic modes in the structure – then the spontaneous emission can be completely suppressed. Conversely, the rate of spontaneous emission can be greatly enhanced if the atom is placed at the location of a defect in the photonic crystal, where the mode density is very high. This last effect is called the Purcell effect. We are currently researching the interesting dynamics of spontaneous emission in photonic crystals with multiple, coupled-cavity defect states [5,7,9,11,12,14,15]. We use a projected Green tensor approach to calculate the local density of states and spontaneous emission dynamics. We have found that the radiation dynamics can be very interesting in such structures. In particular, the spontaneous emission rate can be either enhanced or diminished due to quantum-path interference effects in the structure. This is demonstrated in the plot to the left, where we plot the local density of states for a double-cavity structure showing a large peak in the defect near x=-2 but a dip in the defect near x=+3. This approach makes it much easier to understand the basic physics of multiple-defect structures and has possible implications for quantum-computing applications of photonic crystals. More recently [9], we have been examining quantum optics in photonic crystal waveguides in the strong coupling limit. Until recently, such calculations were prohibitive due to the complexity of the system. However our new projective techniques make a wide variety of complex structure amenable to investigation. These results are leading to a better understanding of the role of quantum path interference in photonic crystals.
