Group Members

Research activity

After the demonstration of the photonic crystals effectiveness by Dominique Labilloy, we now try to develop new applications of photonic crystals for optoelectronics. We are currently investigating two major paths :

the physics of light extraction : can we improve the efficiency of light emitting diodes ?
photonic integrated circuits : towards the ultimate compacity ?

Our research relies mainly on two original experimental set-ups which allows us to determine the optical properties of planar photonic crystals in the near infrared around 1 µm and around the telecom wavelength, 1.55 µm. On the pictures below, you can see our setup around 1 µm.

Both of these setups are based on the internal probe method, which is explained on the figure below. The planar photonic crystals patterns are etched in a 2D-confining vertical heterostructure, in which one or more active layers, consisting of quantum wells or quantum dots, are embedded. Once excited with a focused laser, these active layers act as an in-plane source. The photoluminescence, guided by the vertical heterostructure and travelling from the excitation point to the cleaved edge of the sample, is then collected by a microscope objective and spectrally analyzed. The same spectral analysis can be done for the frontal photoluminescence, scattered by the photonic crystals. The major advantage of this internal probe method is to allow quantitative measurements of the optical properties of the photonic crystals.

We use as well predictive tools : a calculation method based on a two-dimensional plane-wave expansion allows a modal analysis of photonic crystal structures. We also dispose of a modelling tool based on Sakoda's method (in two dimensions) developed by Daniel Ochoa in EPFL.