1D Confocal Broad Area Semiconductor Lasers (Confocal BALs) for Fundamental Transverse Mode Selection (TMS#0)

Figure 6

Top and middle row: near- and far-field intensity distributions for the confocal BAL with a 32 μm wide constriction in the middle plane. Gaussian fits (red lines) are added for both intensity distributions as guides to the eye. The laser has been operated around 90 K in continuous-wave emission. Bottom: side-view sketch and top-view scanning electron micrograph (SEM) of one of the dry-etched mirror-facets. The radiation is partially diffusely reflected or scattered off the somewhat rough substrate plateau, which has resulted from the dry-etch process to define the mirror-facets.