Researchers have designed a bio-inspired blueprint for a new laser system that can convert natural sunlight into a coherent laser beam.
They believe that one day such sunlight-powered lasers could be used in place of fossil fuels to kickstart chemical processes, such as those for the energy-intensive production of fertiliser.
Conventional lasers are powered by electrical energy from a battery or the grid. Even if renewable generation electricity is used, this requires additional infrastructure and energy is invariably lost along the way.
In a study published in the New Journal of Physics scientists from Heriot-Watt University’s Institute of Photonics and Quantum Sciences have outlined how their new sunlight-powered laser could work, explaining that their design takes inspiration from nature.
‘Sunlight is abundant, but because it is dilute and variable, it is difficult to collect, store and harness,’ said Dr Erik Gauger, who worked with a team of colleagues from Italy and Mexico on the study. ‘Nature has already found a way to do this through photosynthesis, when plants turn sunlight, water and carbon into food and energy.’
Gauger and his colleagues therefore turned to purple bacteria – a group of photosynthetic organisms found in ponds and lakes – for inspiration for their new system.
‘Purple bacteria have ring-like antennae which have a reaction centre in their middle that allows them to convert sunlight to chemical energy,’ Gauger explained. ‘If we can find a way to strip out the reaction centres and replace them with a much simpler structure, we could use a bunch of those modified photosynthetic structures to convert sunlight into a laser beam under ambient conditions.
Pictorial representation of the researcher's design principle. (Image: Francesco Mattiotti et al)
‘We have all these ingredients available, we just need to find the best way to play molecular lego and assemble the structures.’
While solar-powered lasers are already being worked on by other groups of scientists, those demonstrated so far need elaborate systems and high levels of refrigeration, according to Gauger.
‘Our design would be self-contained and neither require an external power source, nor complicated large surrounding lenses,’ he said. ‘It would be lightweight and portable and made using entirely natural, organic components. It would constitute the ultimate source of green energy.’
In the paper the researchers describe that the end result could be a solar-powered laser that while being low energy would still useful for a range of applications.
‘Solar-powered lasers could be used to generate green energy or to bring about chemical processes,’ said Gauger. ‘This could tackle the carbon footprint of processes like the production of fertiliser, which is currently responsible for 1-2 per cent of global energy consumption. This is hugely exciting. We could use one of our most abundant resources to help reach net zero.’
Read the full paper here.
