CCD致冷技术在小型光谱仪降噪中的应用

与传统光谱仪相比，小型光谱仪在性能上存在着较大的差距，光度准确度较差、信噪比低等问题限制了其在弱光检测中的应用。分析小型光谱仪的噪声来源及其抑制方法，结合CCD设计了其致冷结构，并采用半导体致冷技术对自行设计的小型光谱仪进行了降噪处理。测量了不同温度下CCD的暗电流，发现致冷对CCD噪声起到很好的抑制作用；在此基础上，参照分光光度计的国家机械行业标准和计量检定规程，测量了致冷条件下小型光谱仪的光度噪声和基线平直度。结果表明：致冷能有效地提高仪器的性能，实验用小型光谱仪的光度噪声为±0.002Abs，基线平直度为±0.004Abs。

Application of CCD refrigeration in the miniaturized spectrometer

Compared to the traditional spectrometers,the miniature spectrometer is poor in noise and photometric performance. These problems limit its application in the detection of weak light signals. The noise sources of miniature spectrometers were analyzed and different kinds of techniques used for decreasing the noise were introduced. To enhance the capabilities of a selfdeveloped miniature spectrometer,the semiconductor cooling technology was used to decrease the noise. Based on the size of CCD,the structure of refrigerator was designed to improve the cooling efficiency. The noise sources of linear CCD were analyzed and the dark current at different temperatures was tested. The photometric noise and baseline flatness were tested according to the national industry standard. The results show that refrigeration is useful in limiting noise. The photometric noise of the miniature spectrometer is±0.002 Abs,and the baseline flatness is ±0.004 Abs.