Research groups have sought to fabricate nitride-based laser diodes because of their applications in optical storage systems, printing, medical surgery and chemical monitoring. Now a team of scientists from the University of California at Santa Barbara and the US Air Force's Wright Laboratories in Dayton, Ohio, has demonstrated favorable results using two types of sapphire substrates, one fabricated using reactive ion-etched facets on c-plane sapphire and the other cleaved facets on a-plane sapphire. The group performed pulsed operation at 420 nm with threshold current densities as low as 10.6 kA/cm2, output powers as high as 77 mW and lifetimes in excess of 6 hours. The diodes operated up to a maximum ambient temperature of 95 °C and pulse lengths up to 150 ns.