Single-material coupling-tolerant semi-planar microresonator using Littrow diffraction

Henri Benisty (1)

1 Laboratoire Charles Fabry de l'Institut d'Optique / Naphel

Resonators carved in a single material such as disc, rings, spheres, do not require genuine mirrors since they exploit shape resonances, but they then suffer from poor coupling to standard free-space collimated beams. Exploiting the idea of Littrow resonators combining total internal reflection and grating diffraction, we propose trapezoidal prism-type geometries that include a strong grating on one face, and total internal reflection on the other face. Resonant modes are localized within a length of the same order as the prism thickness, but are well coupled to free-space beams. The resonator core can be seen as a broad waveguide with multimode coupling of ‘‘Littrow modes'', a configuration recently pointed out for its capability to produce a ‘‘collective'' slow-light regime. A more ‘‘planar'' version, with a saw-tooth input-coupling grating for vertically collimated beam is also proposed.

Mots clés: Resonators; Gratings; Littrow diffraction; Surface coupling; Flat bands; Slow light

Domaines: Optique [physics.optics]

Henri Benisty. Single-material coupling-tolerant semi-planar microresonator using Littrow diffraction. Photonics and Nanostructures - Fundamentals and Applications, 2009, 7 (3), pp.115. ⟨10.1016/j.photonics.2009.02.001⟩. ⟨hal-00567026⟩