Electrically pumped VCSEL emits blue light
An electrically pumped blue-light-emitting vertical-cavity surface-emitting laser (VCSEL) was to be described by researchers from Matsushita Electric Co. (Osaka, Japan) in a paper at the Device Research Conference (Charlottesville, VA) in June. The electrically pumped device was developed based on work involving a pulsed optically pumped VCSEL that produces blue laser output at wavelengths near 488 nm; it was reported earlier this year by a group of researchers from the University of California (UCSB, Santa Barbara, CA), University of Notre Dame (Notre Dame, IN), Matsushita Electric Co., and University of Tsukuba (Tsukuba, Japan).
The vertical-cavity resonator structure of the optically pumped VCSEL was fabricated with SiO2/SiN distributed Bragg reflectors (DBRs) and a CdZnSe/ZnSe strained-layer superlattice active region. It was excited through the top DBR—closest to the superlattice active region—by 5-ns pulses at a repetition rate of 30 Hz from a 420-nm dye laser pumped at 355 nm by a Q-switched Nd:YAG laser. Laser emission was monitored from the bottom DBR. The device lases at thresholds of about 44 kW/cm2 at a temperature of 30 K, and, according to UCSB researcher Philip Floyd, its lifetime is likely to be equivalent to that of an edge-emitting device.