Hello everybody,

I am looking for a good way to make an optical fiber a light guide that
is also electrically conducting. The fiber will be used to focus the
light beam below 1 micron spot diam.

I have "theoretical options" in mind:
1) use a doped quartz fiber, (conductivity might be low), to which the
extremity is tapered by pulling the fiber near the melting point, then
smoothing by etching in HF,
2) or use a quartz fiber coated ITO (the conductivity is acceptable).
Avoid the deposition of thick film ITO on the fiber end.
3) or use crystalline  ITO rod, the end is tapered by mechanical
polishing then etched.
4) or use a quartz fiber coated silver and polish  the end with slurry.
Then etch the quartz non isotropically at slow rate to make a spherical
lens. Prior to that protect the silver coating with probably a
photoresist.
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Please comment on these options,
For option 3) is there any particular anisotropic etching for ITO
crystals ?
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Is there any other option, easier that can guaranty good result?
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Is any one knows who can make my device?
Eventually who can provide a ready device?
Are there references?

Thank you for your cooperation.
ankar