Tiny Peaks vs Mega Backgrounds: A General Spectroscopic Method with Applications in Resonant Raman Scattering and Atmospheric Absorptions
Tiny Peaks vs Mega Backgrounds: A General Spectroscopic Method with Applications in Resonant Raman Scattering and Atmospheric Absorptions
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DOI：
10.1021/ac301696p
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发表时间：
2012-09-18
影响因子：
7.4
通讯作者：
Etchegoin, Pablo G.
中科院分区：
文献类型：
--
作者：
Auguie, Baptiste;Reigue, Antoine;Etchegoin, Pablo G.
描述了一种简单的方法，使用带有电荷耦合器件(CCD)探测器的标准光谱仪，在信号由被更强(多达105)的宽广背景所吞没的微弱光谱特征(例如拉曼峰或吸收线)组成的情况下，常规地测量背景校正光谱。该方法的原理是减去主要的固定结构噪声，得到有限的散粒噪声谱。因此，通过足够的积分时间，可以根据需要降低最终噪声电平。该方法需要对衍射栅进行多次移位来提取像素相关的噪声结构，然后将其用作平场校正。提出了一种新颖的峰值恢复过程，在常规方法不适用的实际例子中展示了对峰值线形和线宽的准确确定和稳健性。举例说明了该技术的潜力，以执行常规的共振拉曼测量荧光染料的高量子产率，使用传统的拉曼系统。该方法同样可以应用于其他小特征被广泛的压倒性背景所掩盖的情况。给出了大气气体弱吸收谱线测量的一个具体例子。
A simple method using standard spectrometers with charge-coupled device (CCD) detectors is described to routinely measure background-corrected spectra in situations where the signal is composed of weak spectral features (such as Raman peaks or absorption lines) engulfed in a much stronger (by as much as 105) broad background. The principle of the method is to subtract the dominant fixed-structure noise and obtain a shot-noise limited spectrum. The final noise level can therefore be reduced as desired by sufficient integration time. The method requires multiple shifts of the diffraction gratings to extract the pixel-dependent noise structure, which is then used as a flat-field correction. An original peak-retrieval procedure is proposed, demonstrating accurate determination of peak lineshapes and linewidths and robustness on practical examples where conventional methods would not be applicable. Examples are discussed to illustrate the potential of the technique to perform routine resonant Raman measurements of fluorescent dyes with high quantum yield, using conventional Raman systems. The method can equally be applied to other situations where small features are masked by a broad overwhelming background. An explicit example is given with the measurement of weak absorption lines in atmospheric gases.