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Surface optical Bloch oscillations in semi-infinite waveguide arrays.
1Department of Applied Mathematics, University of Crete, Heraklion 71409, Crete, Greece. jochremm@central.ntua.gr
Optics Letters
|June 5, 2012
Summary
Surface optical Bloch oscillations are predicted in semi-infinite waveguide arrays. Perturbing boundary parameters enables these oscillations, offering a "matched" termination to prevent Bloch oscillation distortion from boundary reflections.
Area of Science:
- * Photonics and Waveguide Optics
- * Condensed Matter Physics
Background:
- * Optical Bloch oscillations (OBOs) describe the oscillatory motion of wave packets in periodic potentials under a uniform external field.
- * Waveguide arrays mimic such potentials, but boundary reflections can distort OBOs.
- * Surface states in semi-infinite systems are crucial for understanding boundary effects.
Purpose of the Study:
- * To predict the existence of surface optical Bloch oscillations (SOBOs) in semi-infinite waveguide arrays.
- * To identify conditions for achieving SOBOs through boundary parameter perturbation.
- * To explore the application of SOBOs as a boundary termination for preserving OBOs.
Main Methods:
- * Theoretical analysis of semi-infinite waveguide arrays with linear index variation.
- * Introduction of specific boundary parameter perturbations to induce SOBOs.
- * Investigation of the relationship between array parameters (index gradient, coupling) and the number of perturbed waveguides.
Main Results:
- * Surface optical Bloch oscillations can be realized in perturbed semi-infinite waveguide arrays.
- * The perturbation ensures surface states acquire the Wannier-Stark ladder eigenvalues of the unperturbed infinite array.
- * The required number of perturbed waveguides decreases as the ratio of index gradient to coupling increases.
Conclusions:
- * SOBOs are predicted to exist in appropriately perturbed semi-infinite waveguide arrays.
- * This phenomenon provides a method for creating
- matched
- waveguide array terminations.
- * Such terminations can effectively eliminate OBO distortion caused by boundary reflections.
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