Lambert Joseph G, Hernandez-Diaz Carlos, Williamson J Charles
Department of Physics, Drexel University, Philadelphia, Pennsylvania 19104, USA.
Rev Sci Instrum. 2010 Jan;81(1):013110. doi: 10.1063/1.3287951.
Spectrometers configured with charge-coupled devices (CCD) or other array-based detectors require calibration to convert from the pixel coordinate to a spectral coordinate. A CCD calibration method well suited for Raman spectroscopy has been developed based on the 514.5 nm Ar(+) laser-induced fluorescence (LIF) spectrum of room-temperature molecular iodine vapor. Over 360 primary and secondary I(2) LIF calibration lines spanning 510-645 nm were identified as calibrant peaks using an instrumental resolution of 1 cm(-1). Two instrument calibration functions were evaluated with these peaks: a second-order polynomial and a function derived from simple optomechanical considerations. The latter function provided better fitting characteristics. Calibration using I(2) LIF was tested with measurements of both laser light scattering and Raman spectra. The I(2) LIF reference spectra and the signal spectra were recorded simultaneously, with no cross talk, by separating the two signals spatially along the vertical axis of the CCD imager. In this way, every CCD image could be independently calibrated. An accuracy and a precision of +/-0.05 cm(-1) were achieved with this calibration technique.
配置有电荷耦合器件（CCD）或其他基于阵列探测器的光谱仪需要进行校准，以便从像素坐标转换为光谱坐标。基于室温分子碘蒸气的514.5 nm氩离子（Ar(+)）激光诱导荧光（LIF）光谱，已开发出一种非常适合拉曼光谱的CCD校准方法。使用1 cm(-1)的仪器分辨率，在510 - 645 nm范围内识别出超过360条一级和二级I(2) LIF校准线作为校准峰。用这些峰评估了两种仪器校准函数：二阶多项式和基于简单光机械考虑得出的函数。后一种函数具有更好的拟合特性。使用I(2) LIF进行校准，通过对激光散射和拉曼光谱的测量进行了测试。通过沿着CCD成像器的垂直轴在空间上分离这两个信号，同时记录I(2) LIF参考光谱和信号光谱，且无串扰。通过这种方式，每个CCD图像都可以独立校准。使用这种校准技术实现了±0.05 cm(-1)的准确度和精密度。
