Modal approach for tailoring the absorption in a photonic crystal membrane

Romain Peretti (1) , Guillaume Gomard (1, 2) , Christian Seassal (1) , Xavier Letartre (1) , Emmanuel Drouard (1)

1 INL - Photonique - INL - Nanophotonique
2 INL - PV - INL - Photovoltaïque

In this paper, we propose a method for tailoring the absorption in a photonic crystal membrane. For that purpose, we first applied Time Domain Coupled Mode Theory to such a subwavelength membrane and demonstrated that 100% resonant absorption can be reached even for a symmetric membrane, if degenerate modes are involved. Design rules were then derived from this model in order to tune the absorption. Subsequently, Finite Difference Time Domain simulations were used as a proof of concept and carried out on a low absorbing material (extinction coefficient=10-2) with a high refractive index corresponding to the optical indices of amorphous silicon at around 720 nm. In doing so, 85% resonant absorption was obtained, which is significantly higher than the commonly reported 50% maximum value. Those results were finally analyzed and confronted to theory so as to extend our method to other materials, configurations and applications.

Mots clés: Multilayers; complex dielectric constant; absorption; reflection and transmission coefficients; emissivity) Elemental semiconductors and insulators Semiconductors; superlattices; metamaterials Elemental semiconductors Amorphous semiconductors Optical constants (including refractive index; photonic structures

Domaines: Optique [physics.optics]

Romain Peretti, Guillaume Gomard, Christian Seassal, Xavier Letartre, Emmanuel Drouard. Modal approach for tailoring the absorption in a photonic crystal membrane. Journal of Applied Physics, 2012, 111 (123114), pp.123114 - 123114-7. ⟨10.1063/1.4730443⟩. ⟨hal-00834756⟩