Polarization effects in near-field excitation-collection probe optical microscopy of a single quantum dot.
J Microsc
; 194(Pt 2-3): 421-5, 1999.
Article
em En
| MEDLINE
| ID: mdl-11388279
ABSTRACT
We solve numerically the three-dimensional vector form of Maxwell's equation for the situation of near-field excitation and collection of luminescence from a single quantum dot, using a scanning near-field optical fibre probe with subwavelength resolution. We highlight the importance of polarization-dependent effects in both the near-field excitation and collection processes. Applying a finite-difference time domain method, we calculate the complete vector fields emerging from a realistic probe structure which is in close proximity to a semiconductor surface. We model the photoluminescence from the quantum dot in terms of electric dipoles of different polarization directions, and determine the near-field luminescence images of the dot captured by the same probe. We show that a collimating effect in the high index semiconductor significantly improves the spatial resolution in the excitation-collection mode. We find that the spatial resolution, image shape and collection efficiency of near-field luminescence imaging strongly depend on the polarization direction as represented by the orientation of the radiating electric dipoles inside the quantum dot.
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Base de dados:
MEDLINE
Idioma:
En
Revista:
J Microsc
Ano de publicação:
1999
Tipo de documento:
Article