Title: Low-coherence interferometry with undetected mid-infrared photons in the high-gain regime Show Chinese title

Title: 高增益 regime 中未探测中红外光子的低相干干涉术

Abstract: We develop a high-parametric-gain SU(1,1) interferometer based on an aperiodically poled Potassium Titanyl Phosphate (apKTP) crystal, enabling frequency-domain low-coherence interferometry with undetected mid-infrared photons. The system achieves a signal-to-noise ratio as high as 40 dB and axial resolution of 30 $\mu$m, with a 3 $\mu$m-centered idler beam. By increasing the poling-period range, we also improve the axial resolution to 17 $\mu$m, demonstrating a straightforward route to enhance the performance by working on the crystal design Show Chinese abstract

Abstract: 我们开发了一种基于非周期性极化的钾钛氧磷酸盐（apKTP）晶体的高参数增益SU(1,1)干涉仪，实现了在频域内使用未检测到的中红外光子的低相干干涉测量。 该系统实现了高达40 dB的信噪比和30 $\mu$m的轴向分辨率，其中心波长为3 $\mu$m的闲频光束。 通过增加极化周期范围，我们还将轴向分辨率提高到17 $\mu$m，展示了通过改进晶体设计来提升性能的简单途径。