Subwavelength-diameter silica wires for low-loss optical waveguiding
The present invention provides nanometer-sized diameter silica fibers that exhibit high diameter uniformity and surface smoothness. The silica fibers can have diameters in a range of a about 20 nm to about 1000 nm. An exemplary method according to one embodiment of the invention for generating such fibers utilizes a two-step process in which in an initial step a micrometer sized diameter silica preform fiber is generated, and in a second step, the silica preform is drawn while coupled to a support element to form a nanometer sized diameter silica fiber. The portion of the support element to which the preform is coupled is maintained at a temperature suitable for drawing the nansized fiber, and is preferably controlled to exhibit a temporally stable temperature profile.
1. A fiber, comprising
a silica nanowire having a diameter (D) in a range of about 20 nm to about 1000 nm and a length (L) in a range of about 1 millimeter to about 100 millimeters,
wherein the nanowire exhibits a diameter uniformity over the length L of said nanowire that is less than about 10 −3 , said diameter uniformity being defined as
Δ
D
L
,
wherein ΔD is a maximum diameter variation over the length L.
2. The fiber of claim 1 , wherein said diameter uniformity is in a range of about 2×10 −5 to about 10 −3 .
3. The fiber of claim 1 , wherein said diameter of said nanowire is in a range of about 20 nm to about 500 nm.
4. The fiber of claim 1 , wherein said diameter of said nanowire is in a range of about 20 nm to about 50 nm.
5. The fiber of claim 1 , wherein said silica nanowire has an amorphous composition.
6. The fiber of claim 1 , wherein said silica nanowire has a root-mean-square sidewall roughness less than about 0.2 nm.
7. The fiber of claim 1 , wherein said diameter of said nanowire is in a range of about 500 nm to about 1000 nm.