Design of red PCSELs with rotatable double-ellipse for single-mode and high-power operation

Abstract Photonic-crystal surface-emitting lasers (PCSELs) can deliver watt-level, diffraction-limited emission from millimeter-scale, lens-free systems. However, scaling this performance to high-power red PCSELs remains challenging, as strong intrinsic absorption in III-V materials obstructs the integration in a common platform for embedded air holes and substrate-side emission. Here we introduce a novel red-emission PCSEL based on the air-column architecture that breaks the mirror symmetry of the double-lattice photonic-crystal along <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>y</mml:mi> <mml:mo>=</mml:mo> <mml:mi>x</mml:mi> </mml:math> diagonal to enhance its output efficiency. Three-dimensional coupled-wave theory (3D-CWT) combined with multi-parameter scanning is employed to quantify the radiative ability, inter-modal crosstalk, and coupling strength in infinite structures, as well as to extract the slope efficiency and threshold margin of finite devices. The optimized double-ellipse lattice with a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>14</mml:mn> <mml:mi mathvariant="normal">°</mml:mi> </mml:math> rotation yields a high slope efficiency of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>0.82</mml:mn> <mml:mspace width="0.5em"/> <mml:mi mathvariant="normal">W</mml:mi> <mml:mspace width="0.5em"/> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">A</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="italic">−</mml:mi> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> while maintaining robust transverse-mode discrimination and exhibiting tolerance to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>±</mml:mo> <mml:mn>0.01</mml:mn> </mml:math> variations in the filling factor. Our work demonstrates that the symmetry deliberately broken by rotation in plane geometry provides an additional degree of freedom for maximizing the radiation efficiency of double-lattice PCSELs and enables a compact high-brightness red laser design for laser display and medical lighting.