自发拉曼光谱作为表征物质结构的分子光谱，具有非接触、高特异性和快速响应等优点，已被广泛应用于食品安全监管、生物医学研究、矿物分析、人体组织诊断和毒品爆炸物检测等领域。自发拉曼光谱仪器是获取自发拉曼光谱信号的直接工具，仪器的性能决定了获取的拉曼光谱信号质量。然而，自发拉曼光谱信号十分微弱，测量过程中样品荧光、环境光等干扰会降低拉曼峰信噪比，极大损害信号质量，严重影响定性和定量分析结果的准确性。因此，开展对自发拉曼光谱中荧光干扰和环境光干扰抑制方法的研究，有利于提高自发拉曼光谱仪器性能。本文针对现有干扰抑制方法的不足，开展如下工作：在非对称重加权惩罚最小二乘法的基础上，通过反平方根函数建立了权重因子的数学模型，提出了改进非对称重加权惩罚最小二乘法对模拟和真实拉曼光谱进行基线校正，解决了非对称重加权惩罚最小二乘法基线过估计及基线校正速度慢的问题，提高了复杂荧光背景下的拟合精度和拟合速度。提出了双波长组合拉曼光谱方法躲避荧光和扩展光谱范围，建立了785 nm/830 nm双波长激发组合拉曼光谱系统，通过计算不同区域的特征峰强度比值结果，构建了食用油种类分布图，实现了包括大豆油、玉米油、亚麻籽油等十种食用油的快速分类。建立了785 nm波段双波长差分拉曼光谱系统，解决了可口可乐检测中荧光高、无法检测的难题，实现了食品安全领域中非法掺酒可乐的检测，检测范围可达4.76 ~ 50 %；面对芬太尼国家监管重大需求，将双波长差分拉曼光谱技术与表面增强拉曼光谱技术相结合，提出了表面增强差分拉曼光谱方法，实现了饮料基质中芬太尼的痕量检测，掺毒饮用水和掺毒脉动维生素饮料最低检测浓度分别为10 ng/mL和200 ng/mL。相比公开报道的表面增强拉曼光谱方法，表面增强差分拉曼光谱方法将水中芬太尼的最低检测浓度由100 ng/ml改善至10 ng/ml，提升了一个数量级。首次将移频激发差分拉曼光谱方法应用于抑制远程拉曼光谱中环境光干扰，建立了双波长广域照明差分拉曼光谱系统，实现了不同强度环境光干扰下的远距光谱探测。结果表明该系统对光谱信噪比的提高超过3倍，最大探测距离为9.2 m。此外，还开展了模拟实际条件下岩矿成分以及爆炸物原料的白天时段开放式探测。

As a molecular spectroscopy of substances, spontaneous Raman spectroscopy, with the advantages of being non-contact, high sensitivity and rapid response, has been widely applied in many fields, such as food safety, biological research, mineral analysis, tissue diagnosis, and explosive detection. However, the baselines in the raw Raman spectra drift due to fluorescence from organic molecules and ambient light from environment in the measurement, which lowers the signal-to-noise ratio (SNR) of the Raman spectra and reduces the accuracy of qualitative and quantitative analyses. In order to enhance the performance of spontaneous Raman spectroscopy instruments, the structure of this thesis is as follows:Firstly, a baseline correction method based on improved asymmetrically reweighted penalized least squares (IarPLS) was presented for the Raman spectrum. This method utilizes a new S-type function to reduce the risk of baseline overestimation and speed up the reweighting process. Considering the drawbacks of the weighting rules for the asymmetrically reweighted penalized least squares (arPLS) method, we adapted an inverse square root unit (ISRU) function, which performs well in baseline correction. Experiments with the simulated Raman spectra have confirmed that the proposed method yields better outcomes, compared with previous penalized least squares methods, such as asymmetric least squares, adaptive iteratively reweighted penalized least squares, and arPLS. Experiments with the measured Raman spectra show that the IarPLS method can correct real Raman spectra within 20 ms.Secondly, a dual-wavelength excitation combined Raman spectroscopy (DWECRS) system at 785 and 830 nm was developed to reduce the risk of fluorescence interference. By a common optical path, each laser beam was focused on the same region of the sample by a single objective lens, and the dual-wavelength excitation Raman spectra were detected by a single CCD detector; in addition, 785 and 830 nm excitation Raman spectra can be directly constructed as combined Raman spectrum in the DWECRS system. The results of pure peanut oil and glycerol indicate that the combined Raman spectrum can not only reduce fluorescence interference, but also keep a high signal-to-noise ratio in the high-wavenumber region. The results of dye-ethanol solutions with different concentrations show that the handheld DWECRS system can be used as a smart method to dodge strong fluorescence. Furthermore, we developed a peak intensity ratio method with the DWECRS system to distinguish different types of edible oils. The peak intensity ratio distribution chart of edible oils shows each oil normalized center was relatively independent and nonoverlapped, which can be used as the basis of edible oil classification analysis.Thirdly, a dual-wavelength rapid excitation Raman difference spectroscopy (DWRERDS) system was developed to separate Raman signals from background interference. In the DWRERDS system, a dual-wavelength diode laser at 784.59 nm and 785.22 nm with volume Bragg gratings was used as the excitation light source. For each laser line, optical power can reach as high as 550 mW. Under dual-wavelength excitation mode, the DWRERDS system can switch between each laser instantaneously and the excitation time of each laser is as short as 1 s. Two Raman spectra are measured with slightly shifted excitation wavelengths and subtracted from each other, resulting in a background-free difference spectrum. The DWRERDS system is applied to complex matrix background suppression, which can achieve a very good signal-to-noise ratio (SNR) for Raman spectra. Although ethanol in Coca-Cola cannot be detected by conventional Raman spectroscopy, the DWRERDS system can be used for the direct detection of ethanol in illegal alcoholic beverages. The experimental results show that the limit of detection (LOD) of ethanol in Coca-Cola was a volume percentage of 4.76% and the correlation coefficient for the linear regression was so high as 0.984.In recognition of the misuse risks of fentanyl, there is an urgent need to develop a useful and rapid analytical method to detect and monitor the opioid drug. The surface-enhanced shifted excitation Raman difference spectroscopy (SE-SERDS) method was used for trace detection of fentanyl in beverages. To prepare the simulated illegal drug–beverages, fentanyls were dissolved into distilled water or Mizone as a series of test samples. Based on our previous work, the surface-enhanced Raman spectroscopy detection was performed on the beverages containing fentanyl by the prepared AgNPs and the SE-SERDS spectra of test samples were collected by the dual-wavelength rapid excitation Raman difference spectroscopy system. In addition, the quantitative relationship between fentanyl concentrations and the Raman peaks was constructed by the Langmuir equation. The experimental results show that the limits of quantitation for fentanyl in distilled water and Mizone were 10 ng/mL and 200 ng/mL, respectively; the correlation coefficients for the nonlinear regression were as high as 0.9802 and 0.9794, respectively; and the relative standard deviation was less than 15%.In addition, to suppress daylight background interference and obtain a high signal-to-background ratio (SBR), a dual-wavelength wide area illumination Raman difference spectroscopy (WAIRDS) system was developed for daytime remote detection. Measurements of polystyrene indicate that the WAIRDS system can be operated to obtain background-free Raman spectra under different levels of daylight background interference. The remote results show that the improvement in SBR is about three to five fold, and the system can work at distances of up to 9.2 m on a sunny afternoon. Moreover, to be close to the actual detection, the system was used for mineral and explosive raw material detection during daytime measurement.