Browsing by Author "Wijers, CMJ"

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Interband magneto-optical transitions in a layer of semiconductor nano-rings
(2005-06-01)
Voskoboynikov, O
;
Wijers, CMJ
;
Liu, JL
;
Lee, CP
;
應用數學系
We have developed a quantitative theory of the collective electromagnetic response of layers of semiconductor nano-rings. The response can be controlled by means of an applied magnetic field through the optical Aharonov-Bohm effect and is ultimately required for the design of composite materials. We demonstrate that the local field is of paramount importance in the description of such layers. The changes in ellipsometric parameters are 2 to 3 orders of magnitude above the detection limit of a modern ellipsometer.
Left handed composite materials in the optical range
(2005-03-01)
Voskoboynikov, O
;
Dyankov, G
;
Wijers, CMJ
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The purpose of this paper is to show that semiconductor nano-structures built from non-magnetic InAs/GaAs nano-rings can exhibit simultaneously negative effective permittivity and permeability over a certain optical frequency range. The structures are resonant and have this property near the edge of absorption of the nano-rings. This can be particularly interesting in the investigation of the challenging problem of development of left-handed composite materials in the optical range. (c) 2005 Elsevier Ltd. All rights reserved.
Magneto-optical response of layers of semiconductor quantum dots and nanorings
(2005-06-01)
Voskoboynikov, O
;
Wijers, CMJ
;
Liu, JL
;
Lee, CP
;
應用數學系
In this paper a comparative theoretical study was made of the magneto-optical response of square lattices of nanoobjects (dots and rings). Expressions for both the polarizability of the individual objects as their mutual electromagnetic interactions (for a lattice in vacuum) was derived. The quantum-mechanical part of the derivation is based upon the commonly used envelope function approximation. The description is suited to investigate the optical response of these layers in a narrow region near the interband transitions onset, particularly when the contribution of individual level pairs can be separately observed. A remarkable distinction between clearly quantum-mechanical and classical electromagnetic behavior was found in the shape and volume dependence of the polarizability of the dots and rings. This optical response of a single plane of quantum dots and nanorings was explored as a function of frequency, magnetic field, and angle of incidence. Although the reflectance of these layer systems is not very strong, the ellipsometric angles are large. For these isolated dot-ring systems they are of the order of magnitude of degrees. For the ring systems a full oscillation of the optical Bohm-Ahronov effect could be isolated. Layers of dots do not display any remarkable magnetic field dependence. Both type of systems, dots and rings, exhibit an outspoken angular-dependent dichroism of quantum-mechanical origin.
Magneto-optics of layers of semiconductor quantum dots and nano-rings
(2006-06-01)
Voskoboynikov, O
;
Wijers, CMJ
;
Liu, JL
;
Lee, CP
;
交大名義發表
We have studied the collective magneto-optical response of layers of semiconductor quantum dots and nanorings. Expressions for both the polarizability of the individual nano-objects have been used to determine the magneto-optical response on square two-dimensional lattices on those nano-objects as a function on frequency, magnetic field and angle of incidence. The magnetic field dependence of the response for layers of rings gives rise to the Aharonov-Bohm type oscillatory behavior in the reflectance and absorbance that can be measurable. Layers of dots do not display any remarkable magnetic field dependence.