Inhibition of light emission in a 2.5D photonic structure

We analyse inhibition of emission in a 2.5D photonic structures made up a photonic crystal (PhC) and Bragg mirrors using FDTD simulations. A comparison is made between an isolated PhC membrane and the same PhC suspended onto a Bragg mirror or sandwiched between 2 Bragg mirrors. Strong inhibition of the Purcell factor is observed in a broad spectral range, whatever the in-plane orientation and location of the emitting dipole. We analysed these results numerically and theoretically by simulating the experimentally observed lifetime of a collection of randomly distributed emitters, showing that their average emission rate is decreased by more than one decade, both for coupled or isolated emitters.

Absorption enhancement in photonic crystal thin films by pseudo disordered perturbations

The effects resulting from the introduction of a controlled perturbation in a single pattern membrane on its absorption are first studied and then analyzed on the basis of band folding considerations. The interest of this approach for photovoltaic applications is finally demonstrated by overcoming the integrated absorption of an optimized single pattern membrane through the introduction of a proper pseudo disordered perturbation.

Modal approach for tailoring the absorption in a photonic crystal membrane

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.