Researchers explore next-gen UV lasers in fight against COVID-19
In the global rush to control the spread of coronavirus, ultraviolet (UV) light has proven effective for sterilizing surfaces in its prevention. Ideally, light emitting diodes, or LEDs, could provide the UV light.
However, the technological advancements in this realm have remained stalled. As a device, UV lasers with improved beam quality remain better and more suitable for real-world applications.
At The Ohio State University, Electrical and Computer Engineering (ECE) Assistant Professor Shamsul Arafin said this conundrum highlights the importance of materials and device research as technological achievements delve deeper under the microscope. Arafin and ECE Professor Siddharth Rajan recently earned $400,000 from the National Science Foundation to help explore an innovative approach to solve this long-standing issue.
According to their research, ultra-short-wavelength ultraviolet lasers emitting sub-300 nm power have proven useful for sterilizing surfaces or objects in the prevention of the global coronavirus spread. However, energy-inefficient LEDs achieved to-date are large, complicated and expensive, which essentially limits their applicability in these key areas.
Arafin said their NSF proposal, “Tunnel Junction-based AlGaN Ultraviolet Lasers” for the NSF Electrical, Communications and Cyber Systems (ECCS) program will use their findings over the next three years to develop the technology necessary to operate lasers more efficiently in the sterilization process.
The proper technology could have wide-ranging benefits for science in general.
“UV light is useful due to a wide range of emerging applications, including phototherapy in the medical sector, plant growth lighting, water sterilization, trace gas sensing, curing polymers, and stimulating the formation of anti-cancerogenic substances,” said Arafin.
Specifically, Ohio State proposes an innovative approach to utilize interband tunnel junctions (TJs), which alleviate the material conductivity and hole injection problems of laser materials without sacrificing the optical performance of the device. This novel approach will, in fact, help overcome the principal challenges by enhancing hole conductivity and carrier transport by generating what are called “mobile holes” at the materials level.
“Mobile hole is an integral component of any optoelectronic device. Without holes, you cannot achieve device operation,” explained Arafin. “The question is, how will you get mobile holes in such devices, which is fundamentally challenging. Our proposed approach will help get enough mobile holes required for lasing operation.”
The ECCS program was developed by NSF to promote fundamental research in device and component technologies. In addition, the scientific insights and technological advances stemming from the research will also broadly impact the field of photonics by enabling operation in this underdeveloped ultraviolet spectral region.
Another goal of such NSF funding is not only to find solutions, but train the next generation of scientists. Because the proposed research project crosses different disciplines of science and engineering, such as optics, materials science, electrical engineering, physics, and chemistry, it will lead to a range of potential, hands-on learning activities that can engage students of varying backgrounds.
by Ryan Horns, Department of Electrical and Computer Engineering