基于钠、钾原子滤光器的双波段原子特征光谱成像技术研究

The imaging spectrometry has both imaging and spectral resolving functions, which can detect the spectrum of the target and realize recognition. Narrower spectral resolution can improve the ability of target recognition, and the spectral resolution at present is generally at the nm level. This project develops dual band atomic characteristic spectral imaging technology research based on sodium and potassium atomic optical filters. Through the development of sodium and potassium atomic optical filters whose transmission spectra are well matched with their atomic spectra, and assembling with optical lenses and cameras, the atomic spectral imaging systems based on atomic filters can be developed. They can realize high signal-to-noise ratio imaging of sodium and potassium atomic spectra respectively. According to the ultra narrow band of the atomic filter, the spectral resolution at the spectral lines of sodium and potassium are narrower than 0.01nm. Because of the widespread existence of sodium and potassium on the earth, most fuels inevitably contain impurities of these two elements. Their combustion spectra generally contain the two characteristic spectra. Therefore, dual band atomic characteristic spectral imaging system based on sodium and potassium atomic optical filters can detect many combustion reactions rapidly and accurately in background noises. It can play an important role in the large-scale fire point monitoring, rapid recognition of dangerous fire and preliminary determine the combustion sources according to the relative intensity of the two bands.

成像光谱仪同时具备成像功能和光谱分辨功能，可探测目标的光谱并进行识别。更窄的光谱分辨率可提高目标识别的能力，而目前其光谱分辨率一般在nm级。本项目开展基于钠、钾原子滤光器的双波段原子特征光谱成像技术研究，通过研制透射谱与原子特征谱匹配良好的钠、钾原子滤光器，并搭配光学镜头和相机形成基于原子滤光器的原子特征谱成像系统，可分别实现钠、钾原子特征谱的高信噪比成像。根据原子滤光器的超窄带滤光效果，其在钠、钾原子特征谱线处的光谱分辨率窄于0.01nm。由于钠、钾元素在地球上广泛存在，大部分的燃料都不可避免的含有这两种元素的杂质，燃烧光谱普遍包含这两种特征谱。因此，基于钠、钾原子滤光器的双波段原子特征光谱成像技术，可在自然背景环境中快速准确检测到燃烧反应，从而在大范围燃烧点监测、快速发现危险火源等场景中发挥重要作用，并根据两个波段的相对强度特点初步判断燃烧物种类。

由于钠、钾元素在地球上广泛存在，大部分的燃料都不可 避免的含有这两种元素的杂质，燃烧光谱普遍包含这两种特征谱。因此，基于钠、钾原子滤光器的双波段原子特征光谱成像技术，可在自然背景环境中快速准确检测到燃烧反应，从而在大 范围燃烧点监测、快速发现危险火源等场景中发挥重要作用，并根据两个波段的相对强度特点 初步判断燃烧物种类。.我们完成了一种钠、钾波段窄带原子滤光成像实验系统的研制工作。我们设计了透射峰与原子共振吸收线频率对准的窄带原子滤光器，具有很高的峰值透射率和极窄的通带带宽。通过改进磁场设计，这些滤光器的视场可达10度以上，便于用于成像系统中。使用这种钠、钾波段窄带原子滤光成像实验系统可在复杂背景光噪声环境中对钠、钾原子特征光源进行成像，探测信噪比相对于使用了10nm滤光片的系统提高了25dB以上。