Scientists from the Naval Research Laboratory in Washington and Hughes Research Laboratory in Malibu, Calif., reported that a vertical cavity surface-emitting laser (VCSEL) offers a number of advantages over single-mode edge-emitting lasers. Surface-emitting lasers do not require distributed feedback gratings and require less processing. They also have a much lower pump threshold than edge emitters.
The VSCELs operated at 2.9 µm, considerably longer than the 1.7-µm wavelengths of most edge-emitting lasers. The lasing linewidths were low, and the researchers obtained pulsed operation at room temperature.