We measure the spatial extent of individual photonic states that are localized by residual disorder in a slow-light photonic crystal waveguide. The size of the states is measured by locally perturbing them individually through an electromagnetic interaction with a near-field probe. We identify localized states that are not observed in transmission and show that they are shorter than the waveguide length. We also obtain near-field measurements of the participation ratio, from which the size of the states is also derived, in quantitative agreement with the size measured with the perturbation method.

APS
dx.doi.org/10.1103/PhysRevB.86.155153
Phys. Rev. B

Spasenović, M, Beggs, D.M, Lalanne, P, Krauss, T.F, & Kuipers, L.K. (2012). Measuring the spatial extent of individual localized photonic states. Phys. Rev. B, 86(Article number: 155153), 1–5. doi:10.1103/PhysRevB.86.155153