Materials

A key research subject at COBRA is the enhancement of the optical properties of materials. Most of the research is done in exploring optical nonlinearities, such as finding out how the output signal (e.g. light) of specific materials changes non-proportionally to its input signal (e.g. electrical current).

Such exploration of new materials requires strong skills in materials assessment. Characterization tools need to be developed that allow us to understand electrical, physical and optical aspects of materials, down to the atomic scale. The exploration of novel structures at the nanoscale, such as quantum wells and dots, and how to make them useful for optical telecommunications are key research subjects. This is especially daunting as the integration of photonic components requires optical functions to be performed with extremely low energy consumption, preferably at femtojoule (fJ) or even single-photon levels.

An outstanding achievement of the Materials’ group is to have been the first academic research group to realize a quantum-dot laser for the 1.55 micrometer (μm) wavelength range. This research is a good example of how the interaction between COBRA’s materials research and work in devices can lead to innovations in communications. Several journal publications have resulted from this (Anantathanasarn, 2006).