TY - JOUR
T1 - Inducing maximal localization with fractal waveguide arrays
AU - Guglielmon, Jonathan
AU - Rechtsman, Mikael C.
N1 - Funding Information:
M.C.R. acknowledges the National Science Foundation under Award No. ECCS-1509546, the Charles E. Kaufman Foundation under Grant No. KA2017-91788, a supporting organization of the Pittsburgh Foundation, the Packard foundation under Fellowship No. 2017-66821, and the Alfred P. Sloan Foundation under Fellowship No. FG-2016-6418.
Publisher Copyright:
© 2019 American Physical Society.
PY - 2019/6/5
Y1 - 2019/6/5
N2 - The ability to transmit light through an array of closely packed waveguides while minimizing interwaveguide coupling has important implications for fields such as discrete imaging and telecommunications. Proposals for achieving these effects have involved phenomena ranging from flat bands to Anderson localization. An approach based on Anderson localization is beneficial since every eigenstate localizes and this localization is applicable to arbitrarily large propagation distances, even in the presence of perturbations such as higher-neighbor couplings. However, the localization lengths can be large so that sites within a given finite region can exhibit significant crosstalk. Here, we pose an optimization problem in which we seek to maximally confine the eigenstates. We demonstrate that, for strongly detuned waveguides arranged in an equally spaced lattice in one dimension (1D) and a square lattice in two dimensions (2D), optimal eigenstate localization can be achieved by fractal potentials. We further show that these structures possess a localization-delocalization phase transition in both 1D and 2D. The structures are related to a more general family of self-similar potentials that can be constructed on the class of k-partite lattices satisfying the property that each sublattice forms a rescaled copy of the original lattice. The structures may also be approximated by a family of periodic structures, and we characterize the performance of these approximations in comparison to the full aperiodic structures.
AB - The ability to transmit light through an array of closely packed waveguides while minimizing interwaveguide coupling has important implications for fields such as discrete imaging and telecommunications. Proposals for achieving these effects have involved phenomena ranging from flat bands to Anderson localization. An approach based on Anderson localization is beneficial since every eigenstate localizes and this localization is applicable to arbitrarily large propagation distances, even in the presence of perturbations such as higher-neighbor couplings. However, the localization lengths can be large so that sites within a given finite region can exhibit significant crosstalk. Here, we pose an optimization problem in which we seek to maximally confine the eigenstates. We demonstrate that, for strongly detuned waveguides arranged in an equally spaced lattice in one dimension (1D) and a square lattice in two dimensions (2D), optimal eigenstate localization can be achieved by fractal potentials. We further show that these structures possess a localization-delocalization phase transition in both 1D and 2D. The structures are related to a more general family of self-similar potentials that can be constructed on the class of k-partite lattices satisfying the property that each sublattice forms a rescaled copy of the original lattice. The structures may also be approximated by a family of periodic structures, and we characterize the performance of these approximations in comparison to the full aperiodic structures.
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U2 - 10.1103/PhysRevA.99.063807
DO - 10.1103/PhysRevA.99.063807
M3 - Article
AN - SCOPUS:85067407689
VL - 99
JO - Physical Review A
JF - Physical Review A
SN - 2469-9926
IS - 6
M1 - 063807
ER -