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O: Fachverband Oberflächenphysik

O 83: Poster Session VI: Poster to Mini-Symposium: Infrared nano-optics IV

O 83.3: Poster

Wednesday, March 3, 2021, 13:30–15:30, P

Nonlocal response of polar dielectric systems — Christopher Gubbin and •Simone De Liberato — School of Physics and Astronomy, University of Southampton, Southampton, United Kingdom

Surface phonon polaritons hosted in polar nanostructures are fast becoming a leading platform for mid-infrared nanophotonics, permitting deep sub-diffraction energy localisation in comparatively low-loss modes. Recent experiments have demonstrated that as polar resonators approach the nanoscale their optical response diverges from that predicted using a local dielectric model [1, 2]. Although this divergence can be explained by microscopic ab-initio methods it is impractical to apply these intensive calculations to optical systems. To solve this issue we develop a nonlocal dielectric theory which captures the essence of the material response by accounting for propagating phonon modes in the dielectric. Unlike in plasmonic nonlocality these modes can propagate into the host medium, yielding a discrete spectrum and unique phenomenology. In this talk I outline our theory [3], its applications to nanoscale polar resonators [4] and superlattices [5], and finally discuss some of the predicted features, including the impact on the resonator spectral response and quality factor.

[1] D. C. Ratchford et al., ACS Nano 13, 6730 (2019).

[2] C. R. Gubbin et al., Nat. Comm. 10, 1682 (2019).

[3] C. R. Gubbin et al., Phys. Rev. X 10, 021027 (2020).

[4] C. R. Gubbin et al., Phys. Rev. B 102, 201302(R) (2020)

[5] C. R. Gubbin et al., Phys. Rev. B 102, 235301 (2020)