Team develops world’s first tunable blue semiconductor laser

In a new study, researchers at Osaka University have developed the world’s first compact, tunable blue semiconductor laser. This is a major advance in far-ultraviolet light technology, which has potential applications in sterilization and disinfection.

This innovative laser employs a specially designed periodic slot structure in a nitride semiconductor, enabling a blue wavelength laser that is practical and adaptable to a variety of disinfection technologies. The research is published in the journal Applied Physics Express.

The research team previously used a horizontal quasi-phase matching device made of aluminum nitride and a vertical microcavity wavelength conversion device incorporating an SrB4O7 nonlinear optical crystal to generate second harmonics at wavelengths below 230 nm. It was proven.

These advanced devices typically require large and expensive ultrashort pulsed lasers as excitation sources. However, to realize a practical far-UV light source, a blue semiconductor laser with a wavelength of around 460 nm is required.

Blue nitride semiconductor lasers were originally designed for Blu-ray technology, but their use has expanded to process metal materials such as copper and gold, and they are expected to find applications in next-generation laser displays. However, these blue lasers oscillate at multiple wavelengths.

Highly efficient wavelength conversion devices have very narrow wavelength tolerance bandwidths, making single-wavelength lasers ideal as pump sources. Additionally, precise wavelength control and tunability are also essential. Several single-wavelength blue lasers with coarse periodic structures have been reported, but none have achieved tunable wavelength control.

“Our tunable nitride semiconductor laser oscillates in the 405 nm band, but its structure can easily be adapted to the 460 nm band,” explains lead author Taisei Kusui. “Combining this laser with our new wavelength conversion device enables the creation of a compact and practical far-UV light source that is safe for continued use in indoor environments, allowing for effective and continuous sterilization and disinfection. It will be.”

With its compact design and long lifespan, this technology can be seamlessly integrated into household appliances such as refrigerators and air conditioners, providing a wide range of public health benefits and contributing to a healthier and safer living environment.