Optimization of Diffractive Optical Element for Designing Compact Snapshot Imaging Spectrometer

As a commonly used instrument, imaging spectrometers can measure the 3-D data cube of targets. In order to detect the spectral information of dynamic targets, different kinds of snapshot spectral imaging technologies have been proposed. Among them, the diffractive optical element-based snapshot imaging spectrometer (DOE-SIS) can significantly reduce the volume of instruments. However, all existing diffractive optical element (DOE) systems were equipped with color sensors, which introduce inaccuracies into the calibrated point spread functions (PSFs) and detected images. In this article, we optimized and proposed a joint design DOE coupled with a monochrome sensor to eliminate the errors. To increase the diversity of the PSFs for coding spectral information, the outer part of the joint-DOE was the spiral structure with parameters chosen by two proposed performance indicators. In contrast, the inner portion was a specially designed circular structure that could enhance the central concentration properties of the PSFs for enhancing spatial performance. The superior performance of the proposed joint design technique was validated by extensive simulation and physical experiments.