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Full-Text Articles in Engineering
Theory, Figures Of Merit, And Design Recipe Of The Plasmonic Structure Composed Of A Nano-Slit Aperture Surrounded By Surface Corrugations, Guangyuan Li, Feng Xiao, Kun Li, Kamal Alameh, Anshi Xu
Theory, Figures Of Merit, And Design Recipe Of The Plasmonic Structure Composed Of A Nano-Slit Aperture Surrounded By Surface Corrugations, Guangyuan Li, Feng Xiao, Kun Li, Kamal Alameh, Anshi Xu
Research outputs 2012
We theoretically investigate a widely-used plasmonic structure composed of a nano-slit aperture surrounded by surface corrugations. A systematical semi-analytical theory in form of two nested coupled-mode models is developed to provide intuitive physical pictures. Based on the theory, figures of merit (FoMs) of the structures designed for normal and for oblique incidence/beaming are defined for the first time to incorporate the interlinks among key structural parameters, making global optimization simple and efficient. Both the theory and the FoMs are quantitatively validated with exhaustive calculations and shown to be highly accurate on performance prediction and structural optimization. With the theory and …
Modeling Of Low Coherence Interferometry Using Broadband Multi-Gaussian Light Sources, Paul Jansz, Steven Richardson, Graham Wild, Steven Hinckley
Modeling Of Low Coherence Interferometry Using Broadband Multi-Gaussian Light Sources, Paul Jansz, Steven Richardson, Graham Wild, Steven Hinckley
Research outputs 2012
Using a low coherence interferometry (LCI) model, a comparison of broadband single-Gaussian and multi-Gaussian light sources has been undertaken. For single-Gaussian sources, the axial resolution improves with the source bandwidth, confirming the coherence length relation that the resolution for single Gaussian sources improves with increasing spectral bandwidth. However, narrow bandwidth light sources result in interferograms with overlapping strata peaks and the loss of individual strata information. For multiple-Gaussian sources with the same bandwidth, spectral side lobes increase, reducing A-scan reliability to show accurate layer information without eliminating the side lobes. The simulations show the conditions needed for the resolution of …
Unidirectionally Optical Coupling From Free Space Into Silicon Waveguide With Wide Flat-Top Angular Efficiency, K Li, G Li, Feng Xiao, Fan Lu, Zhonghua Wang, A Xu
Unidirectionally Optical Coupling From Free Space Into Silicon Waveguide With Wide Flat-Top Angular Efficiency, K Li, G Li, Feng Xiao, Fan Lu, Zhonghua Wang, A Xu
Research outputs 2012
A grating coupling scheme from free-space light into silicon waveguide with a remarkable property of wide flat-top angular efficiency is proposed and theoretically investigated. The coupling structure is composed of two cascaded gratings with a proper distance between their peak angular efficiencies. A quantitative semi-analytical theory based on coupled-mode models is developed for performance prediction and validated with the fully vectorial aperiodic Fourier modal method (a-FMM). With the theory, wide flat-top angular response is achieved and the conditions are pointed out. Proof-of-principle demonstrations show that the -1 dB angular widtha figure of merit to evaluate the flat-top performanceis broadened to …