Phys.org June 27, 2023
Large-area lasers that emit high output powers have lower beam quality due to the introduction of higher-order modes. An international team of researchers (Turkey, USA – Michigan Technological University) has demonstrated a new type of electrically pumped, large-area edge-emitting lasers that exhibited a high-power emission and a high-quality beam. These characteristics were enabled by establishing a quasi PT-symmetry between the second-order mode of a large area two-mode laser cavity and a single-mode auxiliary partner cavity. This in turn enlarges the effective volume of the higher-order modes. As a result, a selective pump applied via current injection into the main laser cavity could provide a stronger modal gain to the fundamental mode, and thus lead to lasing in the single mode regime after filtering out higher order transverse modes. The experimental results are in good agreement with both theoretical and numerical analysis. The material platform and fabrication process are compatible with the industrial standards of semiconductor lasers. This work provides the first clear demonstration of the utility of PT-symmetry in building laser geometries with enhanced performance and, at the same time, useful output power levels and emission characteristics… read more. Open Access TECHNICAL ARTICLE
Quasi PT-symmetric laser. Credit: Light: Science & Applications volume 12, Article number: 149 (2023)Â