Abstract. In a homeland security setting, the ability to detect explosives at a distance is a top security priority. Consequently, the development of remote, noncontact detection systems continues to represent a path forward. In this vein, a remote detection system for excitation of infrared emissions using a CO2 laser for generating laser-induced thermal emission (LITE) is a possible solution. However, a LITE system using a CO2 laser has certain limitations, such as the requirement of careful alignment, interference by the CO2 signal during detection, and the power density loss due to the increase of the laser image at the sample plane with the detection distance. A remote chopped-laser induction system for LITE detection using a CO2 laser source coupled to a focusing telescope was built to solve some of these limitations. Samples of fixed surface concentration (500 μg / cm2) of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) were used for the remote detection experiments at distances ranging between 4 and 8 m. This system was capable of thermally exciting and capturing the thermal emissions (TEs) at different times in a cyclic manner by a Fourier transform infrared (FTIR) spectrometer coupled to a gold-coated reflection optics telescope (FTIR-GT). This was done using a wheel blocking the capture of TE by the FTIR-GT chopper while heating the sample with the CO2 laser. As the wheel moved, it blocked the CO2 laser and allowed the spectroscopic system to capture the TEs of RDX. Different periods (or frequencies) of wheel spin and FTIR-GT integration times were evaluated to find dependence with observation distance of the maximum intensity detection, minimum signal-to-noise ratio, CO2 laser spot size increase, and the induced temperature increment (ΔT).

中文翻译：

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使用激光诱导热发射远程检测高爆炸药红外发射的调制激光源感应系统

摘要。在国土安全环境中，远距离检测爆炸物的能力是安全的首要任务。因此，远程、非接触式检测系统的发展继续代表前进的道路。在这方面，使用 CO2 激光器产生激光诱导热发射 (LITE) 来激发红外发射的远程检测系统是一种可能的解决方案。但是，使用CO2激光器的LITE系统具有一定的局限性，例如需要仔细对准，检测过程中受CO2信号的干扰，以及由于样品平面处的激光图像随着检测距离的增加而导致的功率密度损失。 . 使用耦合到聚焦望远镜的 CO2 激光源进行 LITE 探测的远程斩波激光感应系统旨在解决其中一些限制。1,3,5-trinitroperhydro-1,3,5-triazine (RDX) 的固定表面浓度 (500 μg/cm2) 样品用于远程检测实验，距离范围为 4 到 8 m。该系统能够通过与镀金反射光学望远镜 (FTIR-GT) 耦合的傅立叶变换红外 (FTIR) 光谱仪以循环方式在不同时间热激发和捕获热发射 (TE)。这是通过使用一个轮子阻止 FTIR-GT 斩波器捕获 TE 来完成的，同时用 CO2 激光器加热样品。当轮子移动时，它挡住了 CO2 激光并允许光谱系统捕获 RDX 的 TE。评估车轮旋转的不同周期（或频率）和 FTIR-GT 积分时间，以找出与最大强度检测观察距离的相关性，