Stroud Jasper R, Plusquellic David F
National Institute of Standards and Technology, Boulder, CO, 80305, USA.
Sci Rep. 2025 May 25;15(1):18154. doi: 10.1038/s41598-025-00684-1.
We describe an electro-optic dual-comb system that operates in the near-infrared (near-IR) region to generate optical frequency combs in the near-UV by sum frequency generation in two configurations. The near-IR frequency combs are generated using chirped pulses that down convert the optical information into the radio frequency (RF) domain by a difference in the chirp bandwidths. Near-UV combs at twice the near-IR bandwidth are obtained by sum frequency generation in a nonlinear crystal and detected by a hybrid photon counting detection system. We compare the results of studies of Rb near 420 nm using two optical arrangements where the near-IR combs are mixed in the crystal as combined or as separated beams. While the latter method enables phase retrievals, the combined beam method is superior for phase stability, power throughput for detection, ease of alignment and detection sensitivity. High order interleaving enables near-UV bandwidths near 4 cm for faint photonic sensing and spectroscopic applications. We demonstrate its utility as a high-resolution instrument for column detection of the toxic pollutant, NO. The harmonic generation method is easily extendable across much of the titanium sapphire tuning range for detection of other trace gases.
我们描述了一种电光双梳系统，该系统在近红外（near-IR）区域运行，通过两种配置中的和频产生在近紫外区域生成光学频率梳。近红外频率梳是使用啁啾脉冲产生的，这些啁啾脉冲通过啁啾带宽的差异将光学信息下变频到射频（RF）域。通过在非线性晶体中进行和频产生获得近红外带宽两倍的近紫外梳，并由混合光子计数检测系统进行检测。我们比较了使用两种光学配置对420nm附近的铷进行研究的结果，其中近红外梳在晶体中作为组合光束或分离光束进行混合。虽然后一种方法能够进行相位检索，但组合光束方法在相位稳定性、检测的功率通量、对准的 ease of alignment 和检测灵敏度方面更具优势。高阶交错使得在微弱光子传感和光谱应用中能够获得接近4cm的近紫外带宽。我们展示了它作为一种高分辨率仪器用于检测有毒污染物NO的柱的效用。谐波产生方法很容易在大部分钛宝石调谐范围内扩展，用于检测其他痕量气体。
