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Brighter near‐field optical probes by means of improving the optical destruction threshold
Author(s) -
Stöckle R. M.,
Schaller N.,
Deckert V.,
Fokas C.,
Zenobi R.
Publication year - 1999
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1046/j.1365-2818.1999.00524.x
Subject(s) - materials science , coating , aluminium , optical microscope , titanium , corrosion , composite material , metal , thin film , glass tube , tube (container) , optics , optoelectronics , metallurgy , nanotechnology , scanning electron microscope , physics
The optical destruction thresholds of conventionally etched and tube‐etched near‐field optical probes were measured. One of the main advantages of tube‐etched tips is their smooth glass surface after taper formation. Presumably for this reason, a destruction limit of over 120 μJ was obtained, almost twice as large as that of the rougher, conventionally etched fibre probes. The use of additional adhesion layers (Ti, Cr, Co and Ni) between the glass surface and the aluminium coating produced, especially for tube‐etched tips, a significant increase in the optical destruction threshold. With increasingly thin metal coatings, the use of a protection coating that prevents corrosion during aging is recommended. An additional increase in optical stability was achieved by applying mixed‐metal coatings: alternating thin titanium and thick aluminium layers yielded fibre probes with superior properties that achieved average optical destruction thresholds of > 270 μJ. This is an increase in stability of > 400% compared with conventionally fabricated near‐field optical tips.