We demonstrate the possibility to enhance spectroscopic and lidar capabilities of mid-infrared pulsed optical parametric oscillators (OPOs) based on fan-out periodically-poled lithium niobate (fan-out PPLN) by combining their own wavelength tunability with tunable continuous-wave injection seeding. To that effect, we have developed an original test-bed singly-resonant OPO configuration in which continuous wavelength tuning via intracavity translation of the fan-out PPLN is assisted by simultaneous tuning of a narrow-linewidth fiber-coupled seed diode laser. It is shown that such an approach provides strong (at least by one order of magnitude) spectral narrowing, wavelength stabilization and beam-quality improvement for the signal and idler radiations (tunable around 1.54 μm and 3.33 μm, respectively). The achieved spectral narrowing does not noticeably affect the OPO output pulse energy, but allows fine wavelength tuning and significantly increases the power spectral density which can be available at an analyzed gas absorption line. Thus, it leads to a noticeable increase in sensitivity of the photoacoustic gas sensing carried out with the developed OPO. We have achieved an almost double (∼80%) increase in the photoacoustic response of a methane detector to the reference gas mixture with low concentration methane. The application of the method can be simply extended to many gas absorptions lines within the range 3.1–3.4 μm, due to the potentially wide tunability of the developed OPO. The demonstrated OPO features simplicity, reliability and energy efficiency. It can advance various LIDAR techniques due to the unique combination of spectral and energy characteristics.

我们证明了通过将其自身的波长可调性与可调连续波注入种子相结合，增强基于扇出周期性极化铌酸锂（扇出 PPLN）的中红外脉冲光学参量振荡器 (OPO) 的光谱和激光雷达能力的可能性. 为此，我们开发了一种原始的试验台单谐振 OPO 配置，其中通过同时调谐窄线宽光纤耦合种子二极管激光器，通过扇出 PPLN 的腔内转换进行连续波长调谐。结果表明，这样的方法提供了强有力的（至少一个数量级）1.54周围频谱收缩，波长稳定和用于信号光束质量的提高和空转辐射（可调谐μ m和3.33 μ米）。实现的光谱变窄不会显着影响 OPO 输出脉冲能量，但允许精细的波长调谐并显着增加可在分析的气体吸收线处获得的功率谱密度。因此，它导致使用开发的 OPO 进行的光声气体传感的灵敏度显着增加。我们已经实现了甲烷探测器对具有低浓度甲烷的参考气体混合物的光声响应几乎翻倍（~80%）增加。该方法的应用可以简单地扩展到3.1-3.4 μ范围内的许多气体吸收线m，由于开发的 OPO 具有潜在的广泛可调性。演示的 OPO 具有简单、可靠和能效的特点。由于光谱和能量特性的独特组合，它可以推进各种激光雷达技术。