Optical microscopy using a glass microsphere for metrology of sub-wavelength nanostructures

A technique that allows direct optical imaging of nanostructures and determines quantitatively geometric nanofeatures beyond the classical diffraction limit by using high-refractive index glass microspheres is introduced. The glass microsphere is put on a nanostructure that is immersed in oil and collects the sample's near-field evanescent wave and transforms it into a propagating one, thereby generating a magnified image in the far-field which is recorded by a conventional oil-immersion microscope objective. Experimental results on nanostructures demonstrates a resolution of similar to lambda/4-lambda/7, where lambda is the illumination wavelength, by using a 60 mu m glass microsphere and a normal wideband halogen lamp as illumination source. A two-dimensional numerical study of the light propagation through a glass microsphere using finite element method (FEM) is performed, providing key insight into the microsphere's superior imaging capability. (C) 2015 Elsevier B.V. All rights reserved.


Published in:
Microelectronic Engineering, 143, 86-90
Year:
2015
Publisher:
Amsterdam, Elsevier
ISSN:
0167-9317
Keywords:
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 Record created 2015-09-28, last modified 2018-03-17

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