Threshold Reducing via Micro Rhombic Lasing Misalignment Step‐Cavity with a Simple and Universal Use

Abstract Nanolasers with low‐threshold operation have been attracting attention for a long time. However, research on methods to lower thresholds has been stagnant and underreported. To provide a generalizable method for reducing thresholds, a stepped array cavity designed in this study is demonstrated to reduce the nanolaser excitation threshold. In the experiment, the rhomboid array cavity is fabricated by 3D printing and covered with Cu film. The mechanism of two cavity (cavity α and β) and five modes is designed and displayed for systematically illustrating the parameters of the different cavities and principles of the different oscillation modes. The lasing behavior of modes 1, 2, 4, and 5 is proved by the photoluminescence spectrum at room temperature with the threshold of 1.53 kW cm −2 , 2.73 kW cm −2 , 66.2 W cm −2 , and 371 W cm −2 . The optimum angle of incidence for obtaining lower thresholds in the range 40°–60° is suggested. The laser generation mechanism and polarization characteristics are provided. Finally, the method developed in this study uses a wide range of materials and gain modes to achieve a universal threshold reduction method. The results indicate that the designed method is effective and scalable for a wide range of typical materials and gain modes.