Browsing by Author "Chu, Shu-Chun"

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Characterization of one-dimension edge roughness from far-field irradiance at subwavelength-scale precision
(2008-04-15)
Chu, Shu-Chun
;
Chern, Jyh-Long
;
光電工程學系
;
Department of Photonics
It is proposed and numerically verified that the one-dimensional edge roughness of test sample can be characterized by far-field irradiance measurement at subwavelength-scale precision with a constructed aperture playing as an optical ruler. The precision of the proposed scheme of measurement could be better than 3%, even when the edge roughness is in subwavelength-scale. The influence of sample thickness on the proposed measurement scheme is also investigated and considered. (C) 2007 Elsevier B.V. All rights reserved.
Equiangular-spiral bent lightpipes with arbitrary bent angle
(2009-05-15)
Chu, Shu-Chun
;
Cheng, Yi-Kai
;
Chern, Jyh-Long
;
光電工程學系
;
Department of Photonics
A recent study proposed the concept of a leakage-free bent lightpipe with an equiangular-spiral shape [S.-C. Chu, J.-L Chern, Opt. Lett. 30 (2005) 3006]. This paper extends the design of a leakage-free equiangular-spiral bent lightpipe with arbitrary-bend-angle and addresses in detail the mathematical formalism required to build such an equiangular-spiral bent lightpipe. Furthermore, a comparison of the proposed equiangular-spiral bent lightpipe and a conventional circular bent lightpipe is provided. Numerical verifications are discussed, and experimental explorations with different bent shapes and angles are carried out for comparison. Results show that equiangular-spiral bent lightpipes with different bent angles exhibit a theoretical 100% transmission with more than 76% efficiency when practically propagating, which is much better than conventional circular bent lightpipes. The output irradiance distributions of bent lightpipes with different bent shapes are also investigated. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.
Equiangular-spiral non-loss bent lightpipe and its applications
(2006-01-01)
Chu, Shu-Chun
;
Chern, Jyh-Long
;
光電工程學系
;
Department of Photonics
A novel bending lightpipe operation scheme with an arbitrary bent angle without light leakage is illustrated in details. Possible applications to a light-splitting element that could split light flux with specified separation ratio, and a light-mixing element that could mix light fluxes from several ports of entrance without light leakage are also shown with case demonstration.
Equiangular-spiral non-loss bent lightpipe and its applications - art. no. 63420S
(2006)
Chu, Shu-Chun
;
Chern, Jyh-Long
;
光電工程學系
;
Department of Photonics
A novel bending lightpipe operation scheme with an arbitrary bent angle without light leakage is illustrated in details. Possible applications to a light-splitting element that could split light flux with specified separation ratio, and a light-mixing element that could mix light fluxes from several ports of entrance without light leakage are also shown with case demonstration.
Retrieving two-dimensional information of the subwavelength variation from far-field irradiance
(2006-10-01)
Chu, Shu-Chun
;
Chern, Jyh-Long
;
光電工程學系
;
Department of Photonics
An eigenvalue-problem approach of blind deconvolution is developed to retrieve the information of two-dimensional subwavelength variation from far-field irradiance with an embedded-aperture configuration with three detectors. A reference signal has been implemented to determine the scaling issue, and hence it allows the exact order of magnitude of the retrieved signals to be estimated correctly. It is shown that the subwavelength variations of a two-dimensional aperture can be identified with a precision of better than a 1% error ratio. (c) 2006 Optical Society of America.