Our current research interests include metamaterials, plasmonics, quantum computing and communications, solar cells, diffraction-unlimited imaging, photonic crystals, relativistic quantum theory, phononic crystals, cryptography, biometrics, and microelectromechanical systems. Although it may seem quite a bit of diversity, manipulation of classical and quantum light is the underlying topic which we actually study.
Metamaterials are periodic structures with subwavelength unit cells which can potentially lead to highly exotic devices such as perfect lenses, invisibility cloaks and quantum levitation. However, isotropy and inherent losses are the two major obstacles preventing them from being reality. Our research in this area mainly focuses on the design and fabrication of fully isotropic negative index metamaterials and possible avenues to minimize the losses.
Contrary to metamaterials, photonic crystals have unit cell sizes comparable to the wavelength. Analogous to electronic bandgap in semiconductors, periodic inclusions in such structures can lead to a complete photonic stop band for a range of frequencies. Introducing defects on otherwise periodic lattice results in acceptor or donor levels in the photonic bandgap. Thus, engineering the band structure can lead to many interesting applications which are perhaps not possible with conventional optics. Photonic crystals are not only nice tools to develop novel devices but also an ideal playground for basic physics. Why we are interested in photonic crystals is intimately related with photonic quantum information science.
Quantum computing and communications is the field of processing information based on quantum mechanical nature of information carriers such as photons and atoms. Quantum superposition and entanglement provide us new resources to solve the most intractable problems outright and to communicate more efficiently and securely. Quantum algorithms, quantum teleportation and quantum cryptography are anticipated to change our lives dramatically, once they are reliably implemented. Major model physical systems include linear optics, cavity QED, superconductors, and trapped ions. World's first commercially viable quantum computing device was built by a Canadian company D-Wave Systems, made of the superconducting element niobium. However, there is a long way to go for a practical quantum computer with a power comparable to an inexpensive PC. None of the proposed physical systems is self-sufficient to build a large-scale quantum computer. We envision planar-light wave integrated circuits assisted with photonic crystals a promising route for compact and robust implementation of large-scale quantum circuits. Especially linear and nonlinear optics and quantum dots in the context of cavity QED are plausible tools to harvest toward practical implementations.
Photonic crystal fibers are microstructured optical fibers which exploit the Bragg scattering in their cladding for enhanced confinement of transmitted signals. It is likely that these fibers will outperform the standard telecom fibers in near future. Improved design and fabrication equipped with smart dispersion engineering will lead to many high-performance devices and systems ranging from fiber lasers, quantum communications and cryptography to light detection and ranging. The latter two are the main directions we pursue in photonic crystal fiber research.
What could be in the intersection of quantum computing and metamaterials? Given the unavoidable losses in metamaterials, one may think there is not much there! However, metamaterials can be used as quantum analog processors to simulate exotic physical systems such as black holes. This is what we exactly explore at the crossroads of classical and quantum electrodynamics.
In an entirely different domain, inspired by its photonic counterpart phononic crystals can provide us unprecedented control over the flow of phonons. This can lead to many interesting applications and basic scientific discoveries. Integrated management of acoustic, heat and electromagnetic waves may have significant impact on novel devices. Our current emphasis is the design, fabrication and testing of wide bandgap structures. One of the potential applications which excites us most is the thermal management.
Beside basic and applied science, we are also interested in research and development of commercial products in a bottom-to-top approach. The development of a microelectromechanical gas sensor and a time and attendance system based on a biometric sensor are the two products we are currently interested.
To learn more about our research vision, please visit our projects!