682 research outputs found
Optical bright and dark states in side-coupled resonator structures
We analyze side-coupled standing-wave cavity structures consisting of Fabry-Perot and photonic crystal resonators coupled to two waveguides. We show that optical bright and dark states, analogous to those observed in coherent light-matter interactions, can exist in these systems. These structures may be useful for variable, switchable delay lines
Electrically-pumped, broad-area, single-mode photonic crystal lasers
Planar broad-area single-mode lasers, with modal widths of the order of tens of microns, are technologically important for high-power applications and improved coupling efficiency into optical fibers. They may also find new areas of applications in on-chip integration with devices that are of similar size scales, such as for spectroscopy in microfluidic chambers or optical signal processing with micro-electromechanical systems. An outstanding challenge is that broad-area lasers often require external means of control, such as injection-locking or a frequency/spatial filter to obtain single-mode operation. In this paper, we propose and demonstrate effective index-guided, large-area, edge-emitting photonic crystal lasers driven by pulsed electrical current injection at the optical telecommunication wavelength of 1550nm. By suitable design of the photonic crystal lattice, our lasers operate in a single mode with a 1/e^2 modal width of 25μm and a length of 600μm
Electrical Characterization of Soil for In-Situ Measurement of Liquefaction Potential
A new method for characterizing the fundamental sand properties with electrical parameters is described. Correlations are established between the electrical parameters and relative density, Dr, cyclic stress ratio, τ/ σ\u270, and the parameter K2max. An electrical probe, used to measure the electrical parameters in situ, is described. Field measurements, taken with the probe at one of the 1906 San Francisco earthquake sites, indicate that this is a viable alternative for the in situ evaluation of liquefaction potential
Patterns of genome size variation in snapping shrimp
Although crustaceans vary extensively in genome size, little is known about how genome size may affect the ecology and evolution of species in this diverse group, in part due to the lack of large genome size datasets. Here we investigate interspecific, intraspecific, and intracolony variation in genome size in 39 species of Synalpheus shrimps, representing one of the largest genome size datasets for a single genus within crustaceans. We find that genome size ranges approximately 4-fold across Synalpheus with little phylogenetic signal, and is not related to body size. In a subset of these species, genome size is related to chromosome size, but not to chromosome number, suggesting that despite large genomes, these species are not polyploid. Interestingly, there appears to be 35% intraspecific genome size variation in Synalpheus idios among geographic regions, and up to 30% variation in Synalpheus duffyi genome size within the same colony
MANAGING CYBERSECURITY AS A BUSINESS RISK FOR SMALL AND MEDIUM ENTERPRISES
Cyberspace has become the “Wild West” of business opportunities for companies. The explosion of growth opportunities has also created substantial cyber insecurity for such companies. Large companies have the budget and resources to manage cybersecurity risks with the ability to hire experts to provide guidance and technology to address problems on a large corporate scale. Small and medium sized enterprises (SME), on the other hand, lack the funding, knowledge, and human capital to sufficient defend itself against the various criminals. This research analyzes three solutions for some of the major categorical problems for SMEs looking to manage cybersecurity risks without necessarily large investments in only highly technical solutions which include community policing for broad cooperation within industries, cyber insurance, and cyber hygiene. The research was based on literature review on existing literature including substantial government policy, and openly available information available on the Internet. Research yielded the necessity of adopting solutions beyond technology in order to improve security and resilience for SMEs. The proposed solutions are ideally applicable under specific scenarios for SMEs. Broad adoption may not yield the necessary security or resilience for companies without a clear understanding of its existing security strateg
Electrically Pumped, Edge-Emitting, Large-Area Photonic Crystal Lasers with Straight and Angled Facets
We propose and demonstrate electrically pumped, edge-emitting, large-area photonic crystal lasers. Effective index-guided and Bragg-guided lasing modes are obtained depending on the design of photonic crystal and facets
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