Hamamatsu Photonics K.K. has successfully oscillated the world's first AlGaN (aluminum gallium nitride) laser diode to emit ultraviolet light at 342 nanometers*, the shortest wavelength for an electrically-driven laser diode. This breakthrough will advance the practical application of UV laser diodes in a variety of fields, including biology and environmental science. Laser diodes in general are convenient, compact devices which have low power consumption and long lifetimes, and are environmentally friendly.