Ultrasharp edge filtering in nanotethered photonic wires

Within a suspended photonic wire, the periodically-spaced nanotethers sustaining the wire can behave as damped transverse resonators that interact with the partially reflecting effect of the wire-tether intersection, and thus modify the Bragg reflection mechanism. This specific resonant mechanism is explored using a transfer matrix model, and is shown to result in an ultrasharp filter edge. This sharp behavior is evidenced experimentally on 300-400-nm-wide InP suspended wires through transmission data and further consolidated by optical low coherence reflectometry time-frequency analysis.