By mimicking features of living systems, self-organizing lasers could lead to new materials for sensing, computing, light sources and displays. While many arti­ficial materials have advanced pro­perties, they have a long way to go to combine the versa­tility and func­tionality of living materials that can adapt to their situation. Now, researchers from Imperial College London and University College London have demonstrated the first spon­taneously self-organizing laser device, which can reconfigure when conditions change. The innovation will help enable the development of smart photonic materials capable of better mimicking properties of biological matter, such as respon­siveness, adaptation, self-healing, and collective behaviour.

ICL-researcher Riccardo Sapienza said: “Lasers, which power most of our technologies, are designed from crystalline materials to have precize and static pro­perties. We asked ourselves if we could create a laser with the ability to blend structure and func­tionality, to reconfigure itself and cooperate like biological materials do. Our laser system can recon­figure and cooperate, thus enabling a first step towards emulating the ever-evolving relation­ship between structure and func­tionality typical of living materials.”

The self-assembling lasers in the team’s experiment consisted of microparticles dispersed in a liquid with high gain. Once enough of these micro­particles collect together, they can harness external energy to produce laser light. An external laser was used to heat up a janus particle  – a particle coated on one side with light-absorbing material –, around which the micro­particles gathered. The lasing created by these micro­particle clusters could be turned on and off by changing the intensity of the external laser, which in turn controled the size and density of the cluster.

The team also showed how the lasing cluster could be trans­ferred in space by heating different janus particles, demons­trating the adapta­bility of the system. Janus particles can also collaborate, creating clusters that have properties beyond the simple adding of two clusters, such as changing their shape and boosting their lasing power. UCL-researcher Giorgio Volpe said: “Nowadays, lasers are used as a matter of course in medicine, telecommuni­cations, and also in industrial production. embodying lasers with life-like properties will enable the development of robust, autonomous, and durable next-generation materials and devices for sensing applications, non-conven­tional computing, novel light sources and displays.” Next, the team will study how to improve the lasers’ autonomous behaviour to render them even more life-like. A first application of the techno­logy could be for next-generation elec­tronic inks for smart displays. (Source: ICL)

Reference: M. Trivedi et al.: Self-organized lasers from reconfigurable colloidal assemblies, Nat. Phys., online 14 July 2022; DOI: 10.1038/s41567-022-01656-2

Link: Complex Nanophotonics, Dept. of Physics, Imperial College London, London, UK