Opt Lett. 2023 Apr 15;48(8):2186-2189. doi: 10.1364/OL.486417.
We report a novel, to the best of our knowledge, and simple technique to lock a 642 nm multi-quantum well diode laser to an external linear power buildup cavity by directly feeding the cavity reflected light back to the diode laser for enhancement of gas Raman signals. The dominance of the resonant light field in the locking process is achieved by reducing the reflectivity of the cavity input mirror and thus making the intensity of the directly reflected light weaker than that of the resonant light. Compared with traditional techniques, stable power buildup in the fundamental transverse mode TEM is guaranteed without any additional optical elements or complex optical arrangements. An intracavity exciting light of 160 W is generated with a 40 mW diode laser. Using a backward Raman light collection geometry, detection limits at the ppm level are achieved for ambient gases (N, O) with an exposure time of 60 s.
我们报告了一种新颖的、据我们所知的简单技术，通过直接将腔反射光反馈回二极管激光器，将 642nm 多量子阱二极管激光器锁定到外部线性功率增强腔，以增强气体 Raman 信号。通过降低腔输入镜的反射率，从而使直接反射光的强度弱于谐振光的强度，实现了锁定过程中谐振光场的主导地位。与传统技术相比，无需任何额外的光学元件或复杂的光学装置，就可以保证基横模 TEM 的稳定功率增强。利用腔内激发光 160W，在 60s 的曝光时间内，对于环境气体（N、O），可以达到 ppm 级的检测限。
