Scientists create world’s first tunable blue laser for sterilization and more

Fabrication process. (a) Formation of p-electrodes and etching masks. (b) Formation of active and slotted channels. (c) SEM image of slotted channel. (d) Deposition of insulator layer and photoresist opening. (e) Insulator layer opening. (f) Metallization and facet coating. Credit: Applied Physics Express (2024).

Researchers at Osaka University have developed the world’s first compact blue laser with tunable wavelengths, marking a major breakthrough in far-ultraviolet (UV) light technology.

This innovation, published in Applied Physics Express, could revolutionize sterilization and disinfection in homes, hospitals, and beyond.

Blue semiconductor lasers were initially created for Blu-ray discs but have since found new uses, such as processing metals like copper and gold.

They are also being explored for next-generation laser displays.

To unlock even more potential, such as producing far-UV light for sterilization, these lasers need to have specific, controlled wavelengths—something traditional blue lasers struggle to achieve.

Far-ultraviolet light, with wavelengths below 230 nanometers, is highly effective at killing bacteria and viruses.

However, generating this light typically requires large and expensive laser systems, making it impractical for everyday use. Scientists have long sought a compact and affordable way to produce this type of light.

The team at Osaka University solved this challenge by designing a special periodically slotted structure using nitride semiconductors.

This allows the blue laser to operate at a precise, tunable wavelength in the 405-nanometer range, with the flexibility to adapt to 460 nanometers. When combined with advanced wavelength conversion devices, such as those the team previously developed, this laser can efficiently produce far-UV light.

Unlike older systems, which rely on large and costly ultrashort-pulse lasers, this new technology is compact, practical, and suitable for continuous operation. “Our new laser can provide effective sterilization and disinfection in a safe and energy-efficient way,” said lead researcher Taisei Kusui.

This blue laser could revolutionize public health by enabling sterilization in everyday appliances. For example, it could be integrated into refrigerators to kill bacteria on food surfaces or in air conditioners to purify indoor air.

Its compact size and extended lifespan make it ideal for widespread use, ensuring healthier living spaces.

This groundbreaking innovation could pave the way for affordable and efficient sterilization tools, reducing the spread of harmful microbes in homes, hospitals, and public spaces.

By combining advanced laser technology with practical design, this tunable blue laser brings us closer to safer and healthier environments for everyone.