Optical pulling using evanescent mode in sub-wavelength channels

Broadband single-mode operation of standard optical fibers by using a sub-wavelength optical wire filter.

We report the use of a sub-wavelength optical wire (SOW) with a specifically designed transition region as an efficient tool to filter higher-order modes in multimode waveguides. Higher-order modes are effectively suppressed by controlling the transition taper profile and the diameter of the sub-wavelength optical wire. As a practical example, single-mode operation of a standard telecom optical...

Mode conversion enables optical pulling force in photonic crystal waveguides

Comparative study of the effective single mode operational bandwidth in sub-wavelength optical wires and conventional single-mode fibers.

We present the first experimental comparison of effective single mode operation bandwidth in sub-wavelength optical wires (SOWs) and conventional single-mode fibers (SMFs). The full transmission spectrum, half-turn bend loss and mode field diameter were measured and compared for a variety of SMFs of different cut-off wavelength and a SOW. The SOW was shown to offer an enormously broadband singl...

Highly selective evanescent modal filter for two-mode optical fibers.

Efficient and selective coupling between a single-mode fiber and the LP(11) mode of a double-mode fiber is demonstrated in an evanescent directional coupler. With greater than 90% coupling to the LP(11) mode, suppression of the coupled power to the lower-order LP(01) mode was measured to be at least 24 dB. This device has application as a modal filter for the construction of in-line all-fiber o...

Generation of Wavelength-independent Sub-wavelength Bessel Beams using Metasurfaces

Bessel beams are of great interest due to their unique non-diffractive properties. Using a conical prism or an objective paired with an annular aperture are two typical approaches to generating zeroth order Bessel beams. However, the former approach has a limited numerical aperture (NA), and the latter suffers from low efficiency since most of the incident light is blocked by the aperture. Furt...