“…For a 2 m diameter taper at a wavelength of 1550 nm, the fraction of power in the core is nearly 96%. 7 Recent discussions on the form of the evanescent field have shown the spatial extent of the radial component of the field to greatly increase for diameters less than 3 m. 7,8 It has also been reported that efficient coupling of light into submillimeter sized silica microspheres is possible for taper diameters up to 4.5 m. 9 The four most widely exploited means of achieving micron-sized tapers are by flame, 5,10,11 CO 2 laser heating, 12 microfurnace, 13,14 and, to a lesser extent, fusion splicer. 4 While subwavelength diameters have been shown to be achievable with the flame method, it presents significant technical challenges.…”