||This course is designed to introduce the principle of diffraction of optical wave and study the means of using the diffraction to perform optical setups in modern optical systems. Diffractive optical element (DOE) can be applied to correct aberrations, light focusing, light splitting, and other novel functions that traditional optical components difficultly or impossibly perform. DOE plays an important role in modern optical technology. The content of this course includes: 1. Principle of optical diffraction, 2. Fourier optics, 3. Design methods of DOE, 4. Applications of DOEs, and 5. Implementation of DOEs.