标题： 定量可比较的相干反斯托克斯拉曼散射（CARS）光谱学：校正相位检索中的误差 显示英文标题

标题： Quantitative, Comparable Coherent Anti-Stokes Raman Scattering (CARS) Spectroscopy: Correcting Errors in Phase Retrieval

摘要： 相干反斯托克斯拉曼散射（CARS）显微光谱技术在生物和材料成像方面展示了巨大的潜力。然而，到目前为止，传播CARS光谱信息的主要机制是伪彩色图像，这明显忽略了大部分的高光谱数据。此外，当前的CARS光谱处理范式并不适合样本间的定量比较。主要限制来自于需要准确测量所谓的非共振背景（NRB），该背景用于从原始光谱中提取化学敏感的拉曼信息。在像素级上测量NRB是一项非平凡的任务；因此，通常使用玻璃或水的参考NRB，导致实际和估计的振幅和相位之间存在误差。在本文中，我们提出了一种新的方法来提取拉曼光谱特征，通过相位去趋势和缩放显著抑制这些误差。经典的纠错方法，如基线去趋势，被证明是不准确的，并且只是掩盖了潜在的错误。通过重新开发通过Kramers-Kronig关系进行相位检索的理论，给出了理论依据，并且我们证明这些结果也适用于基于最大熵方法的相位检索。这种新的纠错方法被实验应用于甘油光谱和组织图像，展示了使用不同NRB估计获得的光谱之间以及在不同仪器上获得的光谱之间明显的一致性。此外，为了便于实施这些方法，我们已将本文中描述的许多工具免费提供下载。 显示英文摘要

摘要： Coherent anti-Stokes Raman scattering (CARS) microspectroscopy has demonstrated significant potential for biological and materials imaging. To date, however, the primary mechanism of disseminating CARS spectroscopic information is through pseudocolor imagery, which explicitly neglects a vast majority of the hyperspectral data. Furthermore, current paradigms in CARS spectral processing do not lend themselves to quantitative sample-to-sample comparability. The primary limitation stems from the need to accurately measure the so-called nonresonant background (NRB) that is used to extract the chemically-sensitive Raman information from the raw spectra. Measurement of the NRB on a pixel-by-pixel basis is a nontrivial task; thus, reference NRB from glass or water are typically utilized, resulting in error between the actual and estimated amplitude and phase. In this manuscript, we present a new methodology for extracting the Raman spectral features that significantly suppresses these errors through phase detrending and scaling. Classic methods of error-correction, such as baseline detrending, are demonstrated to be inaccurate and to simply mask the underlying errors. The theoretical justification is presented by re-developing the theory of phase retrieval via the Kramers-Kronig relation, and we demonstrate that these results are also applicable to maximum entropy method-based phase retrieval. This new error-correction approach is experimentally applied to glycerol spectra and tissue images, demonstrating marked consistency between spectra obtained using different NRB estimates, and between spectra obtained on different instruments. Additionally, in order to facilitate implementation of these approaches, we have made many of the tools described herein available free for download.