Vertical-Cavity Laser Diodes with Low Threshold Current Densities

We report a study of threshold and output power behavior of vertical-cavity surface-emitting laser diodes with respect to the offset between spectral gain and mode position which is of great interest for the design of this laser devices. For an optimal adjustment of gain peak and mirror reflectivity we obtained a minimum threshold current density of less than 400 A/cm², which is to our knowledge the lowest reported value for cw-operating vertical-cavity lasers.