Spatially shaping waves to penetrate deep inside a forbidden gap
| Abstract | It is well known that waves with frequencies within the forbidden gap inside a crystal are transported only over a limited distance—the Bragg length—before being reflected by Bragg interference. Here, we demonstrate how to send waves much deeper into crystals in an exemplary study of light in two-dimensional silicon photonic crystals. By spatially shaping the wave fronts, the internal energy density—probed via the laterally scattered intensity—is enhanced at a tunable distance away from the front surface. The intensity is up to 100× enhanced compared to random wave fronts, and extends as far as 8× the Bragg length, which agrees with an extended mesoscopic model. We thus report a novel control knob for mesoscopic wave transport that pertains to any kind of waves. Note: this paper is featured as a Synopsis in APS Physics (pdf available) by K. Wright. |
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| Authors | R. Uppu, M. Adhikary, C. A. M. Harteveld, and W. L. Vos |
| Year of publication | 2021 |
| Date published | 04/2021 |
| Journal | Phys. Rev. Lett. |
| Volume | 126 |
| Pages | 177402: 1-6 |
| DOI number | 10.1103/PhysRevLett.126.177402 |
| Keywords | 2D photonic crystals, band gaps, Bloch mode, photonic band gap, wave control, Wavefront shaping |