The strongly quantum-confined III-nitride material system fundamentally offers the distinct opportunity to operate at high temperatures (200K or more) for scalable semiconductor cavity quantum electrodynamics. Supported by advances in materials growth, optical spectroscopy, and first-principles modeling, this research examines the combination of InGaN quantum dots with mesoscopic optical cavities for solid-state cavity quantum electrodynamics. Optimization of the materials growth and device nanofabrication is performed, to examine low defect density growth. Single quantum dots are targeted for light emission and its modification, as well as nonclassical optics. This research combines the expertise of two groups: III-nitrides materials growth at the Institute of Materials Research and Engineering (IMRE) in Singapore, and optical characterization and photonic crystals at Columbia University. The devices will be optically probed for the exciton characteristics. Microcavities such as whispering gallery modes and photonic band gap cavities will be examined.
This Materials World Network project enables critical complementary efforts between scientists in the United States and Singapore, providing invaluable experience to the graduate students and senior scientists in different working environments. This collaboration also seeds future efforts in the area of solid-state physics and quantum information processing. This research is complemented with international education and exchange efforts, involving iterated feedback and interactions between the two institutions on materials growth and optical spectroscopy, co-supervision of PhD students, participation of the US personnel internationally, and exchange of senior research staff. Furthermore, high-school teacher and undergraduate student exchanges are supported. To support this international activity, video teleconference reviews are also held. The research developed in this collaborative program will be disseminated on the web as well as through international conferences and publications.
Intellectual Merit: In this project, we advanced the light-material interactions in the solid-state. In this first year, this includes the observations of strong exciton-photon polariton coupling through disorder-induced localized cavity modes, and published in Nature Scientific Reports 3, 1994 (2013). We also demonstrated ultrahigh-Q cavities from disorder localized modes in photonic crystals, with Q factors in the range of 1,100,000 ± 200,000 while preserving wavelength-scale modal volumes. In the second year, we examined the photoluminescence of InGaN/GaN nanostructures for solid-state cavity quantum electrodynamics. Furthermore, we demonstrated the long T2 coherence lifetimes up to ~ 2.1 ps along with a ~ 18 ns spontaneous emission lifetimes (T1) as published in Nature Communications 4, 2152 (2013). In the third year, we further examined photoluminesence in the solid-state including III-nitride nanostructures and nanotubes, fiber coupling and deterministic spatial positioning. We observed transverse Anderson localization in chip-scale photon transport, based on controllable disorder in photonic crystal superlattices. This is accepted for publication at Nature Physics. Broader impact: In this project, strong international collaborations examined the studies of light-material interactions, providing invaluable experience to graduate students and senior scientists in different working environments. This included high-quality materials growth in Singapore, theoretical framework from Germany, and high-quality electron-beam writing of nanostructured photonic crystals from France (Thales). This work supported the studies of graduate and undergraduate students.