Rostock 2019 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 36: Photonics II
Q 36.7: Talk
Wednesday, March 13, 2019, 15:30–15:45, S Gr. HS Maschb.
Investigation of the next-nearest- neighbor-coupling in evanescently coupled dielectric waveguides — •Julian Schulz1, Christina Jörg1 und Georg von Freymann1,2 — 1Physics Department and Research Center OPTIMAS, University of Kaiserslautern, Germany — 2Fraunhofer Institute for Industrial Mathematics ITWM, Kaiserslautern, Germany
The tight-binding model is a simple approximation to describe the dynamics in periodic potentials, such as in solids or photonic crystals. Often in these structures, only the couplings to the next neighboring sites are considered and those further away are neglected. In measurements [1] and simulations of the band structure, however, asymmetries can be seen, which are due to a non-negligible next-nearest-neighbor(NNN)-coupling.
To further investigate the effects of the NNN-coupling, the propagation of light in a chain of adjacent evanescently coupled dielectric waveguides is considered. The fabrication of corresponding waveguide structures follows the direct-laser-writing based principle used in [2].
By arranging the chain in a zig-zag shape, the distance to the NNN and by that, the NNN-coupling can be varied. Two independent simulation methods show, in the case of a non-bended linear chain, that the NNN-coupling is negative. This suggests that the NNN-coupling can be increased to zero, if the correct angle in the zig-zag-arrangement is chosen.
[1] F. Bleckmann, et al., Phys. Rev. B 96, 045417 (2017).
[2] C. Jörg, et al., New J. Phys. 19, 083003 (2017).