Phase-engineered distributed grating reliefs for high-power single-mode 795-nm VCSELs with on-axis emission

We report on 795 nm vertical-cavity surface-emitting lasers (VCSELs) that achieve record-high (10.9 ± 0.4) mW single-mode output power with linear polarization. In our VCSEL concept based on a strongly elongated oxide aperture, a high-order transverse mode is stabilized via distributed grating reliefs (GR) that are positioned on the output facet. To align the phases of the waves from adjacent emission sites, an alternating scheme of GR and dielectric phase-shifting pillars (PP) is introduced, which causes a local phase-shift and transforms the far-field intensity onto the optical axis. This approach is guided by simulations and is experimentally demonstrated. The presented concept for high-order mode stabilization offers a promising route to substantially enhance the single-mode output power of VCSELs while preserving linear polarization and on-axis emission, which is attractive for a broad range of applications, including, for instance, quantum technology and biomedical applications.