EPNRL · Electrically pumped network random lasers

Electrically pumped network random lasers

Random lasers, based on disordered photonic materials with optical gain, are alternative means to generate laser light. They are typically cheaper and simpler to fabricate than conventional lasers, and can be potentially controlled by non-uniform pumping to emit light at a particular frequency or direction, which can be exploited to make complex integrated light sources. However, most random lasers demonstrated are optically pumped, whereas electrical pumping is needed for practical use in technology. The ambition of this MSCA Individual Fellowship (EPNRL - Electrically pumped network random lasers) was to develop electrically pumped random lasers made of semiconductor gain medium that could be integrated on-chip and be dynamically controlled by inhomogeneous pumping. Such a device would be able to switch between different lasing modes at fast speeds and route laser light at different wavelengths out into different waveguides. This functionality would be particularly useful for information processing and help advance the development of optical computing, enabling faster and more energy efficient processors. The proposed idea in this project was to construct novel lasers from a network of III-V semiconductor waveguides. Optical feedback in a network would be obtained by light propagation and interference over multiple paths and recurrent loops. As a prototype, we first demonstrated a network random laser in a self-assembled network made from polymer nanofibers with dye. The objective of this fellowship was to develop network lasers further, fabricating them out of semiconductor gain materials so that they would be more robust (longer device lifetime) and compatible with established photonic chip technology (for electrical injection and integration with passive waveguides). Another objective of the project was to develop a theoretical model using graph theory, which would describe lasing in complex networks, and use this model to design the network lasers by investigating different network topologies. As the semiconductor networks were to be fabricated by lithography, the design of the random lasers could be optimised and enable novel characteristics that could be predicted through the modelling and tested experimentally by inhomogeneous pumping. The fellowship was indeed successful in developing Indium Phosphide network lasers (optically pumped) and showing that network lasers could be controlled to lase in one, two or more arbitrary modes via inhomogeneous optical pumping (both experimentally and theoretically). While further research and engineering is required to make network lasers electrically pumped, the network approach certainly provides a flexible architecture to design, build and realise complex lasers from very simple elements, such as 1D waveguides.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз