原位时间分辨光栅衍射效率光谱测量技术研究

Diffraction grating, as currently the important dispersive element, has been used popularly in spectral analysis, high power laser, integrated circuit, optical communication, optical measurement and many other fields, and spectrum of grating’s diffraction efficiency is one of the most important performance indicators of diffraction grating. At present the most popular method to measure the spectrum of grating’s diffraction efficiency is successively obtaining the diffraction efficiency at each individual wavelength of the whole waveband, the major drawback of this technique is that in one time, only the diffraction efficiency at a single wavelength can be measured by the system, the total time consumed to obtain the full spectrum is therefore so long that dynamic measurement for the spectrum of the grating’s diffraction efficiency in the circumstance for example when the temperature is changing during the measurement would be inaccessible. . In this project, based on the natural feature of the grating under inspection, and using linear CCD detector, we aimed to put forward an in-situ time resolved measuring technique for the spectrum of grating’s diffraction efficiency by a single-shot strategy, spectrum in the range of 900-1100 nm can be obtained in as fast as 10 milisecond with our measuring system, this new in-situ time resolved measuring technique for the spectrum of grating’s diffraction efficiency therefore has great application in the dynamic measuring environment and also in mass industrial manufacturing.

衍射光栅作为重要的色散元件，在光谱分析、强激光、集成电路、光通信、光学精密测量等领域有着广泛的应用，而衍射效率光谱是光栅最重要的性能指标之一。目前国际上普遍采用的光栅衍射效率光谱的测量方法是在逐个入射波长下依次完成扫描测量的，其主要缺点是系统每次只能完成一个波长下衍射效率的测量，整个光谱的测量速度因而非常缓慢（如测量900-1100nm波段范围内的光谱曲线，通常需要3-5分钟左右的时间），这使其无法应用于在诸如显影曝光、温湿度改变等环境参数变化情况下的动态测量。. 本项目拟利用光栅固有的色散特点，借助线阵CCD探测器，通过单次曝光的方式实现原位时间分辨光栅衍射效率光谱的测量，测量技术最快可以在10毫秒之内完成900-1100nm波段范围内光栅衍射效率光谱的测量，该原位时间分辨光栅衍射效率光谱测量技术因而在动态测量有显著的科学价值，同时在大批量工业制造中有着广泛的应用前景。

首先，通过消除现有测量方法中机械运动的方式，项目成功发展了一种快速测量光栅光谱衍射效率的新方法，对于如线密度为1200线/mm的待测光栅，新方法能在亚秒量级完成550-750nm波段范围内光栅光谱衍射效率的测量（现有测量技术大约需要5分钟的时间）。然后，我们对光栅光谱衍射效率新测量方法的误差来源进行了系统分析，并提出了相应的误差校正方法。最后，利用项目发展的测量光栅光谱衍射效率的新方法，我们测量了加热过程中光栅光谱衍射效率的动态变化情况，测量结果揭示了光栅在加热过程中的衰退机制。