Scientists Develop Optical Device for Pathogen Eradication on Surfaces with Human Safety in Mind

Title: Innovative Optical Device Safely Eliminates Pathogens on Surfaces

Caption: AlN-Based Wavelength Conversion Device Developed by Hiroto Honda

In the wake of the COVID-19 pandemic, there has been a heightened interest in the potential of ultraviolet (UV) light to combat disease-causing pathogens. However, traditional technologies like excimer lamps and LEDs, which emit deep-UV light, have faced challenges due to their low efficiency and limited lifespan. Additionally, exposure to the wrong UV wavelengths can pose risks to human cells.

A team of researchers from Osaka University has introduced a groundbreaking approach to generate deep-UV light using an aluminum nitride (AlN) optical device, departing from conventional methods. Their innovation relies on a phenomenon known as “second harmonic generation,” where the frequency of a photon is directly proportional to its energy. This breakthrough research has been published in the journal Applied Physics Express.

In most transparent materials, light behaves linearly, meaning photons do not interact with each other. However, within certain “nonlinear” materials, two photons can combine to form a single photon with double the energy and frequency. In this case, two visible photons merge into a single deep-UV photon within an AlN waveguide, which measures less than one micron in width. A waveguide serves as a transparent channel with specific dimensions, optimized for the easy passage of desired frequencies. By harnessing the nonlinear optical properties of AlN, second harmonic generation is achieved with remarkable efficiency.

Lead author Hiroto Honda explains, “Our novel fabrication technique for generating deep-UV light leverages semiconductor processing methods, enabling precise control of the aluminum nitride crystal’s orientation—an achievement that was previously challenging.”

The deep-UV light produced by this prototype device falls within a narrow range, possessing sufficient energy to eliminate germs while largely remaining safe for human exposure. Senior author Ryuji Katayama states, “Our research findings underscore the feasibility of creating compact and efficient deep-UV disinfection tools without compromising human safety.” The team aspires to further refine this approach, paving the way for commercial devices that consume less energy than existing options.

This pioneering work, detailed in the paper titled “229 nm far-ultraviolet second harmonic generation in a vertical polarity inverted AlN bilayer channel waveguide,” holds promise for developing advanced disinfection technologies. It offers the potential to safeguard public health by effectively eliminating pathogens on surfaces while ensuring the well-being of individuals.

“Researchers Create Optical Device That Can Kill Pathogens on Surfaces While Remaining Safe for Humans” (2023, September 11), retrieved from

Source: Osaka University

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