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The waveguiding, absorption and emission properties of oxidised porous silicon waveguides when impregnated with Nile Blue have been studied. We present m-line measurements before and after the impregnation showing that the effective indices of the modes remain the same. When performing guided luminescence experiments, a structured emission band is measured. Using the refractive index profile extracted from m-line measurements it has been possible to simulate the emission lineshape assuming the observation of an interference pattern formed across the waveguide. We demonstrate that these oscillations appear because in the first hundreds of nanometers the dye concentration is several orders of magnitude higher than in the rest of the sample. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

In this paper we describe a reliable and expedient approach for protyping one-dimensional (1D) photonic crystal (PhC) on optical waveguides using focused ion beam (FIB) lithography (which eliminates the need for photoresist and alignment markers). In particular, we show the detailed fabrication process of three 1D photonic crystal patterns (1) a periodic structure, (2) with micrometre-wide cavity layers, and (3) with one taper element, directly milled onto a silicon nitride/silicon dioxide (Si3N4/SiO2) channel waveguide. Experimental investigations of the devices obtained using ultra-broadband transmittance spectroscopy in the visible and near-infrared frequency ranges (i.e. wavelengths between 0.4 and 1.7 µm) are employed to show photonic band-gap behaviour up to fourth order in the radiative mode region. These results are compared with simulations of both transmission and photonic dispersion behaviour. In addition, we demonstrate the novel effects produced by taper elements on the 1D PhC micro-cavities.

We report on the observation of Anderson localization of near-visible light in two-dimensional systems. Our structures consist of planar waveguides in which disorder is introduced by randomly placing pores with controlled diameter and density. We show how to design structures in which localization can be observed and describe both the realization of the materials and the actual observation of Anderson localized modes by near-field scanning microscopy.