Optical Sciences

Biomolecules and nanostructures

The Optical Sciences group studies the interaction of light and matter. Our current focus is on detection and sensing/imaging with an emphasis on the development of integrated photonics. We are part of Twente University's Department of Science and Technology and member of the MESA+ institute.

 

High definition aperture probes for near-field optical microscopy fabricated by focused ion beam milling

(full pdf)

Veerman JA, Otter AM, Kuipers L, van Hulst NF
APPLIED PHYSICS LETTERS
vol 72 issue 24: p3115-p3117 JUN 15 1998

We have improved the optical characteristics of aluminum-coated fiber probes used in near-field scanning optical microscopy by milling with a focused ion beam. This treatment produces a flat-end face free of aluminum grains, containing a well- defined circularly-symmetric aperture with controllable diameter down to 20 nm. The polarization behavior of the tips is circularly symmetric with a polarization ratio exceeding 1:100. The improved imaging characteristics are demonstrated by measuring single molecule fluorescence. Count rates increase more than o­ne order of magnitude over unmodified probes, and the molecule images map a spatial electric field distribution of the aperture in agreement with calculations. (C) 1998 American Institute of Physics.
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