垂直外腔面发射激光器(VECSEL)可以实现大功率的高光束质量输出。针对外腔制作工艺复杂、腔体结构松散的缺点, 研制了一种介质膜集成衬底表面外腔底面发射激光器。将衬底表面生长的多层介质绝缘薄膜与N-DBR、P-DBR共同构成复合腔结构, 衬底充当外腔。该结构能够抑制高阶模式, 进而优化输出光谱及远场发散角等光束特性。在已有的理论指导下, 制作了有源区直径为200 μm、外腔腔长250 μm的VECSEL。室温下, 向器件连续直流注入3.4 A, 测试得到输出功率为260 mW, 远场发散角的半角宽度为3.8°, 光谱半高全宽为0.046 nm。与常规结构底面发射VCSEL进行比较, 发现VECSEL器件的光束质量得到了明显改善, 实验结果与理论仿真结果有较好的一致性。

Vertical cavity surface emitting laser (VCSEL) with external cavity which is filled by dielectric materials or air can achieve good beam quality and high power. Aiming at the problem of complex production process and loose structure of the external cavity, a kind of surface emitting laser with the dielectric film integrated on external cavity bottom substrate was designed. Multilayer dielectric insulation films grown on the surface of substrate, N-DBR, and P-DBR composed the coupled cavity structure, and the substrate was served as external cavity of VECSEL. This structure can suppress high order mode, so it can optimize the output spectrum and far-field divergence angle of beam characteristics. Based on the previous theory, we manufactured a VECSEL with active area of 200 μm in diameter and external cavity length of 250 μm. The device is carried out with continuous DC current of 3.4 A at room temperature, and the power is 260 mW, the divergence angle of far field is 3.8°, the full width at half maximum of spectrum is 0.046 nm. Obviously, compared with conventional structure of bottom emitting VCSEL, the beam quality of VECSEL devices is improved.