Nonlinear Photon Pair Generation in a Highly Dispersive Medium

Photon pair generation in silicon photonic integrated circuits relies on four wave mixing via the third order nonlinearity. Due to phase matching requirements and group velocity dispersion, this method has typically required TE polarized light. Here, we demonstrate TM polarized photon pair production in linearly uncoupled silicon resonators with more than an order of magnitude more dispersion than previous work. We achieve measured rates above 2.8 kHz and a heralded second order correlation of . This method enables phase matching in dispersive media and paves the way for novel entanglement generation in silicon photonic device

North Korean and Iranian Nuclear Ambitions: Giving Diplomacy a Chance

Presented on April 22, 2010 from 12:30 pm to 02:00 pm in the Student Success Center, Press Room A on the Georgia Tech campusChristopher A. Preble is the director of foreign policy studies. His book, The Power Problem: How American Military Dominance Makes Us Less Safe, Less Prosperous and Less Free, published by Cornell University Press, documents the enormous costs of America's military power, and proposes a new grand strategy to advance U.S. national security. He is also the author of Exiting Iraq: How the U.S. Must End the Occupation and Renew the War against Al Qaeda, and John F. Kennedy and the Missile Gap. In addition to his books, Dr. Preble has published over 100 articles in major publications including USA Today, Financial Times, Wall Street Journal, Philadelphia Inquirer, Reason, National Interest, Foreign Service Journal, and the Harvard International Review. He has also appeared on many television and radio news networks including CNN, MSNBC, Fox News, NPR, and the BBC. Before joining Cato in February 2003, he taught history at St. Cloud State University and Temple University. Preble was a commissioned officer in the U.S. Navy and is a veteran of the Gulf War, having served onboard USS Ticonderoga (CG-47) from 1990 to 1993. Preble holds a Ph.D. in history from Temple University

Insights from application of a hierarchical spatio-temporal model to an intensive urban black carbon monitoring dataset

Existing regulatory pollutant monitoring networks rely on a small number of centrally located measurement sites that are purposefully sited away from major emission sources. While informative of general air quality trends regionally, these networks often do not fully capture the local variability of air pollution exposure within a community. Recent technological advancements have reduced the cost of sensors, allowing air quality monitoring campaigns with high spatial resolution. The 100×100 black carbon (BC) monitoring network deployed 100 low-cost BC sensors across the 15 km2 West Oakland, CA community for 100 days in the summer of 2017, producing a nearly continuous site-specific time series of BC concentrations which we aggregated to one-hour averages. Leveraging this dataset, we employed a hierarchical spatio-temporal model to accurately predict local spatio-temporal concentration patterns throughout West Oakland, at locations without monitors (average cross-validated hourly temporal R 2=0.60). Using our model, we identified spatially varying temporal pollution patterns associated with small-scale geographic features and proximity to local sources. In a sub-sampling analysis, we demonstrated that fine scale predictions of nearly comparable accuracy can be obtained with our modeling approach by using ~30% of the 100×100 BC network supplemented by a shorter-term high-density campaign