Opt Express. 2023 Feb 27;31(5):7265-7276. doi: 10.1364/OE.477019.
Nonlinear interferometers with quantum correlated photons have been demonstrated to improve optical characterization and metrology. These interferometers can be used in gas spectroscopy, which is of particular interest for monitoring greenhouse gas emissions, breath analysis and industrial applications. Here, we show that gas spectroscopy can be further enhanced via the deployment of crystal superlattices. This is a cascaded arrangement of nonlinear crystals forming interferometers, allowing the sensitivity to scale with the number of nonlinear elements. In particular, the enhanced sensitivity is observed via the maximum intensity of interference fringes that scales with low concentration of infrared absorbers, while for high concentration the sensitivity is better in interferometric visibility measurements. Thus, a superlattice acts as a versatile gas sensor since it can operate by measuring different observables, which are relevant to practical applications. We believe that our approach offers a compelling path towards further enhancements for quantum metrology and imaging using nonlinear interferometers with correlated photons.
利用具有量子关联光子的非线性干涉仪已经被证明可以提高光学特性和计量学的性能。这些干涉仪可以用于气体光谱学，这对于监测温室气体排放、呼吸分析和工业应用特别有意义。在这里，我们表明通过部署晶体超晶格可以进一步增强气体光谱学。这是由形成干涉仪的非线性晶体级联排列，允许灵敏度与非线性元件的数量成比例增加。特别是，通过与红外吸收体的低浓度成比例的干涉条纹的最大强度观察到增强的灵敏度，而对于高浓度，干涉可见度测量中的灵敏度更好。因此，超晶格作为一种多功能气体传感器，因为它可以通过测量不同的可观测量来操作，这些可观测量与实际应用相关。我们相信，我们的方法为使用具有关联光子的非线性干涉仪进行量子计量学和成像提供了一条引人注目的途径，可以进一步提高性能。
