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.

American Physical Society (APS)
doi.org/10.1103/PhysRevB.86.155153
Phys. Rev. B

Spasenović, M., Beggs, D. M., Lalanne, P., Krauss, T. F., & Kuipers, 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