High-power dual-wavelength vertical external cavity surface emitting laser enabled by parity-time symmetric cavity design

The cavity design flexibility of Vertical-external-cavity surface-emitting lasers (VECSELs) can be utilized for realizing high-power dual-wavelength sources. By employing partial selective pumping of VECSEL transverse modes and appropriate optimization of the folded V-cavity parameters, we successfully achieved parity-time (PT) symmetric cavity dual-wavelength operation. Through numerical simulations of microcavity standing-wave and propagation modes, we analyzed the evolution process of supermodes with loss-induced suppression and revival of lasing in the PT-symmetric cavity. Experimentally, we established two configurations with center-pumping and PT-symmetric partial pumping for comparative analysis, observing the PT-symmetric dual-wavelength VECSEL with only 5.3% reduction in optical-to-optical conversion efficiency relative to central pumping configurations. In the PT-symmetric cavity under an incident pump power of 32 W, a laser output was achieved, featuring a power of 7 W, a dual-wavelength operation spacing of 2.32 nm, and beam quality factors of M x 2 = 1.31 and M y 2 = 1.34. These results demonstrate that the proposed PT-symmetric cavity design provides a feasible strategy for realizing simultaneous high-power, dual-wavelength operation of VECSELs.