UCSB researchers unveil world`s first violet, non-polar, vertical-cavity lasers
In a leap forward for laser technology, a team at University of California, Santa Barbara, has developed the first violet non-polar vertical-cavity surface-emitting lasers (VCSELs) based on m-plane gallium nitride semiconductors. Led by LED pioneer Shuji Nakamura, the researchers' breakthrough paves the way to higher optical efficiency lasers at greatly reduced manufacturing costs for a variety of applications. “This is the first report of a non-polar VCSEL, which we believe to be one of the biggest breakthroughs in the field of laser diode technology,” explains Nakamura, professor of Materials at UCSB. “The non-polar VCSEL has a lot of advantages in comparison with conventional c-plane devices. One major advantage is that the light polarization is locked to one direction.” “This device could be used for a variety of applications, such as lighting, displays, sensors, and technology that requires energy efficiency and small form-factor,” he adds. VCSELs offer advantages over conventional edge-emitting laser technology for some applications. For example, on-wafer testing of VCSEL arrays during the manufacturing process can save costs compared to edge-emitting lasers that require additional steps before testing. The lasers exhibit low threshold currents, circular and low divergence output beams, and are easily integrated into two-dimensional arrays. The non-polar VCSEL platform also provides high optical gain, which helps to increase optical efficiency of devices. The researchers believes the nonpolar VCSEL could enable new products and applications, such as pico-projectors for smartphones, mobile cinema, and automotive lighting.