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Observation of Anderson localization in disordered nanophotonic structures

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Science  02 Jun 2017:
Vol. 356, Issue 6341, pp. 953-956
DOI: 10.1126/science.aah6822
  • Fig. 1 Deep-subwavelength dielectric multilayer structure and experimental apparatus.

    (A) The multilayer stack is grown on a prism and covered with an absorbing Pt layer. A laser beam is incident at angle Embedded Image on the prism, and the output reflection is measured by a camera. (B) Transmission electron microscopy scan of a vertical cut of the multilayer showing, from bottom to top, the rutile prism material, altering dielectric layers, the Pt layer (the absorber), and free space. (C) Magnified scan of the section in the multilayer marked by the orange rectangle in (B).

  • Fig. 2 Measured reflection compared with effective medium calculation.

    (A) The red and black curves are the measured reflection of transverse-magnetic polarized light from the strong disorder and weak disorder structures versus angle of incidence relative to the critical angle. Dashed cyan curve denotes calculated reflection from a disorder-free structure. The numbers 1, 2, and 3 on the plots indicate, respectively, (1) a sharp 8% dip predicted for the disorder-free case; (2) a disorder-induced reflection peak, above 99%, measured at the same angle for which effective medium theory predicts the dip marked by 1; and (3) a narrow dip corresponding to disorder-enhanced transmission at Embedded Image, where the disorder-free case predicts total internal reflection. (B) and (C) are magnified views of the regions marked by 2 and 3 in (A).

  • Fig. 3 Localized modes, measurement at varying wavelengths.

    (A) Calculated modes for Embedded Image. These modes are responsible for the first three dips in Fig. 2A (from the right) measured for the strong-disorder structure. Specifically, the red curve shows the transmission enhancement mode. (B) Reflection measured for transverse-magnetic polarized light at several wavelengths: 514 nm (green line), 632 nm (red line), and 780 nm (black line). Changing the wavelength changes the response of the structure in a complex way.

  • Fig. 4 Optical sensing of 2-nm variation with deep-subwavelength disordered multilayer structure.

    (A) Reflection from four structures prepared in a nearly identical fashion except for layer 99, a silica layer, with a thickness of 8 nm in multilayers [A] and [A′] (purple and red lines, respectively); 10 nm in multilayer [B] (black line); and 20 nm in multilayer [C] (green line). The reflection from multilayer [A] is easily distinguished from multilayers [B] and [C]. Notably, the distinction between multilayers [A] and [B] shows sensitivity to a 2-nm-thickness difference in one of the layers in the multilayer. By contrast, the reflection in the test-case multilayer [A′] is nearly identical to the reflection from multilayer [A], showing the robustness of reflection in the face of inevitable fabrication errors. (B) Comparison of measured reflection from the strongly disordered structure multilayer [A] (red) and transfer matrix calculation (black), showing the predictive power of transfer matrix theory, despite the inevitable presence of fabrication errors.

Supplementary Materials

  • Observation of Anderson localization in disordered nanophotonic structures

    Hanan Herzig Sheinfux, Yaakov Lumer, Guy Ankonina, Azriel Z. Genack, Guy Bartal, Mordechai Segev

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods
    • Supplementary Text
    • Figs. S1 to S10
    • References