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Articles 1 - 13 of 13
Full-Text Articles in Physical Sciences and Mathematics
Slow-Light Fourier Transform Interferometer, Zhimin Shi, Robert W. Boyd, Ryan M. Camacho, Praveen K. Vudyasetu, John C. Howell
Slow-Light Fourier Transform Interferometer, Zhimin Shi, Robert W. Boyd, Ryan M. Camacho, Praveen K. Vudyasetu, John C. Howell
Mathematics, Physics, and Computer Science Faculty Articles and Research
We describe a new type of Fourier transform (FT) interferometer in which the tunable optical delay between the two arms is realized by using a continuously variable slow-light medium instead of a moving arm as in a conventional setup. The spectral resolution of such a FT interferometer exceeds that of a conventional setup of comparable size by a factor equal to the maximum group index of the slow-light medium. The scheme is experimentally demonstrated by using a rubidium atomic vapor cell as the tunable slow-light medium, and the spectral resolution is enhanced by a factor of approximately 100.
Transients Of The Electromagnetically-Induced-Transparency-Enhanced Refractive Kerr Nonlinearity, John C. Howell, M. V. Pack, R. M. Camacho
Transients Of The Electromagnetically-Induced-Transparency-Enhanced Refractive Kerr Nonlinearity, John C. Howell, M. V. Pack, R. M. Camacho
Mathematics, Physics, and Computer Science Faculty Articles and Research
We report observations of the dynamics of electromagnetically induced transparency (EIT) in a Λ system when the ground states are Stark shifted. Interactions of this type exhibit large optical nonlinearities called Kerr nonlinearities, and have numerous applications. The EIT Kerr nonlinearity is relatively slow, which is a limiting factor that may make many potential applications impossible. Using rubidium atoms, we observe the dynamics of the EIT Kerr nonlinearity using a Mach-Zehnder interferometer to measure phase modulation of the EIT fields resulting from a pulsed signal beam Stark shifting the ground state energy levels. The rise times and transients agree well …
Electromagnetically Induced Transparency Line Shapes For Large Probe Fields And Optically Thick Media, M. V. Pack, R. M. Camacho, John C. Howell
Electromagnetically Induced Transparency Line Shapes For Large Probe Fields And Optically Thick Media, M. V. Pack, R. M. Camacho, John C. Howell
Mathematics, Physics, and Computer Science Faculty Articles and Research
We calculate the line shape and linewidths for electromagnetically induced transparency (EIT) in optically thick, Doppler broadened media (buffer gasses are also considered). In generalizing the definition of the EIT linewidth to optically thick media, we find two different linewidth definitions apply depending on whether the experiment is pulsed or continuous wave (cw). Using the cw definition for the EIT line shape we derive analytic expressions describing the linewidth as a function of optical depth. We also review the EIT line shapes in optically thin media and provide physical arguments for how the line shapes change as a function of …
Wide-Bandwidth, Tunable, Multiple-Pulse-Width Optical Delays Using Slow Light In Cesium Vapor, Ryan M. Camacho, Michael V. Pack, John C. Howell, Aaron Schweinsberg, Robert W. Boyd
Wide-Bandwidth, Tunable, Multiple-Pulse-Width Optical Delays Using Slow Light In Cesium Vapor, Ryan M. Camacho, Michael V. Pack, John C. Howell, Aaron Schweinsberg, Robert W. Boyd
Mathematics, Physics, and Computer Science Faculty Articles and Research
We demonstrate an all-optical delay line in hot cesium vapor that tunably delays 275 ps input pulses up to 6.8 ns and 740 input ps pulses up to 59 ns (group index of approximately 200) with little pulse distortion. The delay is made tunable with a fast reconfiguration time (hundreds of ns) by optically pumping out of the atomic ground states.
Digital Support For Abductive Learning In Introductory Computing Courses, Atanas Radenski
Digital Support For Abductive Learning In Introductory Computing Courses, Atanas Radenski
Mathematics, Physics, and Computer Science Faculty Articles and Research
Students who grew up browsing the Web are skilled in what is usually referred to as abduction, a reasoning process that starts with a set of specific observations and then generates the best possible explanation of those observations. In order to exploit the abduction skills of contemporary students, we have developed digital CS1/2 study packs that promote and support active learning through abduction, i.e., abductive learning. The study packs integrate a variety of digital resources: online self-guided labs, e-texts, tutorial links, sample programs, quizzes, and slides. These online packs stimulate students to learn abductively by browsing, searching, and performing self-guided …
Large-Alphabet Quantum Key Distribution Using Energy-Time Entangled Bipartite States, Irfan Ali-Khan, Curtis J. Broadbent, John C. Howell
Large-Alphabet Quantum Key Distribution Using Energy-Time Entangled Bipartite States, Irfan Ali-Khan, Curtis J. Broadbent, John C. Howell
Mathematics, Physics, and Computer Science Faculty Articles and Research
We present a protocol for large-alphabet quantum key distribution (QKD) using energy-time entangled biphotons. Binned, high-resolution timing measurements are used to generate a large-alphabet key with over 10 bits of information per photon pair, albeit with large noise. QKD with 5% bit error rate is demonstrated with 4 bits of information per photon pair, where the security of the quantum channel is determined by the visibility of Franson interference fringes. The protocol is easily generalizable to even larger alphabets, and utilizes energy-time entanglement which is robust to transmission over large distances in fiber.
All-Optical Delay Of Images Using Slow Light, Ryan M. Camacho, Curtis J. Broadbent, Irfan Ali-Khan, John C. Howell
All-Optical Delay Of Images Using Slow Light, Ryan M. Camacho, Curtis J. Broadbent, Irfan Ali-Khan, John C. Howell
Mathematics, Physics, and Computer Science Faculty Articles and Research
Two-dimensional images carried by optical pulses (2 ns) are delayed by up to 10 ns in a 10 cm cesium vapor cell. By interfering the delayed images with a local oscillator, the transverse phase and amplitude profiles of the images are shown to be preserved. It is further shown that delayed images can be well preserved even at very low light levels, where each pulse contains on average less than one photon.
Improved Associated Conditions In Rapid Intensifications Of Tropical Cyclones, Ruixin Yang, J. Tang, Menas Kafatos
Improved Associated Conditions In Rapid Intensifications Of Tropical Cyclones, Ruixin Yang, J. Tang, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
Rapid intensification (RI) of tropical cyclones (TC) is a major error source in TC intensity forecasting. In order to improve the estimates of RI probability, association rules are used to facilitate the process of mining for candidate sets of conditions. Compared to the relation analysis method, the technique of association rules can simply explore associations among multiple conditions. Our mining results identified a reduced predictor set with fewer factors identified in previous studies but improved RI probabilities. That is, the RI probability with three conditions satisfied: low vertical shear, high humidity, and the TC being in an intensification phase is …
Influences Of Winter Haze On Fog/Low Cloud Over The Indo-Gangetic Plains, Ritesh Gautam, N. C. Hsu, Menas Kafatos
Influences Of Winter Haze On Fog/Low Cloud Over The Indo-Gangetic Plains, Ritesh Gautam, N. C. Hsu, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
The aerosol loading in south Asia has increased considerably because of the growing population, urbanization, and industrialization in recent years. To understand the effects of aerosols on cloud properties in this region, we have analyzed an extensive collection of aerosol and cloud properties, obtained from the Moderate resolution Imaging Spectroradiometer (MODIS) data, over the Indian subcontinent during winter 2000–2006. During these winter months, the Indo-Gangetic (IG) plains, in the northern part of India, are subjected to dense haze and fog on the basis of MODIS climatology of aerosol optical depth and cloud properties (cloud effective radius, cloud top pressure, and …
Note On The Ndvi-Lst Relationship And The Use Of Temperature-Related Drought Indices Over North America, D. Sun, Menas Kafatos
Note On The Ndvi-Lst Relationship And The Use Of Temperature-Related Drought Indices Over North America, D. Sun, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
A comprehensive evaluation of the relationship between vegetation and Land Surface Temperature (LST) over the North America is presented. It is found that the correlations between LST and Normalized Difference Vegetation Index (NDVI) depend on the season-of-year and time-of-day. For winter, the correlation between NDVI and LST is positive. The strong negative correlations between LST and NDVI are only found during the warm seasons. Thus temperature-related drought indices may only be used in the warm seasons from May to October, and should be used with caution during cold seasons in North America. The cooling effect of vegetation on LST is …
Carathéodory Functions In The Banach Space Setting, Daniel Alpay, Olga Timoshenko, Dan Volok
Carathéodory Functions In The Banach Space Setting, Daniel Alpay, Olga Timoshenko, Dan Volok
Mathematics, Physics, and Computer Science Faculty Articles and Research
We prove representation theorems for Carathéodory functions in the setting of Banach spaces.
Generalized No-Broadcasting Theorem, Howard Barnum, Jonathan Barrett, Matthew S. Leifer, Alex Wilce
Generalized No-Broadcasting Theorem, Howard Barnum, Jonathan Barrett, Matthew S. Leifer, Alex Wilce
Mathematics, Physics, and Computer Science Faculty Articles and Research
We prove a generalized version of the no-broadcasting theorem, applicable to essentially any nonclassical finite-dimensional probabilistic model satisfying a no-signaling criterion, including ones with ‘‘superquantum’’ correlations. A strengthened version of the quantum no-broadcasting theorem follows, and its proof is significantly simpler than existing proofs of the no-broadcasting theorem.
A Functional Calculus In A Non Commutative Setting, Fabrizio Colombo, Graziano Gentili, Irene Sabadini, Daniele C. Struppa
A Functional Calculus In A Non Commutative Setting, Fabrizio Colombo, Graziano Gentili, Irene Sabadini, Daniele C. Struppa
Mathematics, Physics, and Computer Science Faculty Articles and Research
In this paper we announce the development of a functional calculus for operators defined on quaternionic Banach spaces. The definition is based on a new notion of slice regularity, see [6], and the key tools are a new resolvent operator and a new eigenvalue problem. This approach allows us to deal both with bounded and unbounded operators.