119 research outputs found
Observation of Nonspreading Wave Packets in an Imaginary Potential
We propose and experimentally demonstrate a method to prepare a nonspreading
atomic wave packet. Our technique relies on a spatially modulated absorption
constantly chiseling away from an initially broad de Broglie wave. The
resulting contraction is balanced by dispersion due to Heisenberg's uncertainty
principle. This quantum evolution results in the formation of a nonspreading
wave packet of Gaussian form with a spatially quadratic phase. Experimentally,
we confirm these predictions by observing the evolution of the momentum
distribution. Moreover, by employing interferometric techniques, we measure the
predicted quadratic phase across the wave packet. Nonspreading wave packets of
this kind also exist in two space dimensions and we can control their amplitude
and phase using optical elements.Comment: 4 figure
Ultrafast all-optical switching in a silicon-nanocrystal-based silicon slot waveguide at telecom wavelengths
This document is the Accepted Manuscript version of a Published Work that appeared in final form in
Nano Letters, copyright Ā© American Chemical Society after peer review and technica editing by the publisher. To access the final edited and published work see http://pubs.acs.org/page/policy/articlesonrequest/index.htmlWe demonstrate experimentally all-optical switching on a silicon chip at telecom wavelengths. The switching device comprises a compact ring resonator formed by horizontal silicon slot waveguides filled with highly nonlinear silicon nanocrystals in silica. When pumping at power levels about 100 mW using 10 ps pulses, more than 50% modulation depth is observed at the switch output. The switch performs about I order of magnitude faster than previous approaches on silicon and is fully fabricated using complementary metal oxide semiconductor technologies.The work was financially supported by the EU through project PHOLOGIC (FP6-IST-NMP-017158).MartĆnez Abietar, AJ.; Blasco Solbes, J.; Sanchis Kilders, P.; Galan Conejos, JV.; GarcĆa-RupĆ©rez, J.; Jordana, E.; Gautier, P.... (2010). Ultrafast all-optical switching in a silicon-nanocrystal-based silicon slot waveguide at telecom wavelengths. Nano Letters. 10(4):1506-1511. doi:10.1021/nl9041017S1506151110
Assessing the human immune system through blood transcriptomics
Blood is the pipeline of the immune system. Assessing changes in transcript abundance in blood on a genome-wide scale affords a comprehensive view of the status of the immune system in health and disease. This review summarizes the work that has used this approach to identify therapeutic targets and biomarker signatures in the field of autoimmunity and infectious disease. Recent technological and methodological advances that will carry the blood transcriptome research field forward are also discussed
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Convergence in international business ethics? A comparative study of ethical philosophies, thinking style, and ethical decision-making between US and Korean managers
This study investigates the relationship among ethical philosophy, thinking style, and managerial ethical decision-making. Based on the premise that business ethics is a function of culture and time, we attempt to explore two important questions as to whether the national differences in managerial ethical philosophies remain over time and whether the relationship between thinking style and ethical decision-making is consistent across different national contexts. We conducted a survey on Korean managersā ethical decision-making and thinking style and made a cross-cultural, cross-temporal comparison with the results presented by previous studies that surveyed Korean and US managers with the same questionnaire at different points in time. Our analysis revealed that Korean managers have become more reliant on rule utilitarianism for ethical decision-making over the last two decades, which is dominantly used by US managers, corroborating our convergence hypothesis built on social contracts theory. However, as opposed to previous research, we found that managers with a balanced linear and nonlinear thinking style do not necessarily make more ethical decisions compared to those with a predominantly linear or nonlinear thinking style. This study contributes to international business ethics literature by presenting a theoretical framework that may explain the convergence of ethical philosophies employed by managers in different national contexts over time, and that the relationship between thinking style and managerial ethical decision-making may not be universal, but contingent on contextual factors
Outlook for inverse design in nanophotonics
Recent advancements in computational inverse design have begun to reshape the
landscape of structures and techniques available to nanophotonics. Here, we
outline a cross section of key developments at the intersection of these two
fields: moving from a recap of foundational results to motivation of emerging
applications in nonlinear, topological, near-field and on-chip optics.Comment: 13 pages, 6 figure
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