Free electron laser (FEL), called the fourth advanced light source, is the most advanced experimental device to explore the microscopic world. It has a transformative driving effect on many subjects, such as energy, physics, chemistry, materials, biology, etc. With the successful research of "comprehensive experimental research equipment based on tunable EUV coherent light source (Dalian Coherent Light Source, DCLS)", China's vacancy in this area has been filled. DCLS could be expected to be the edge tool to promote the development of science and technology in China. This paper briefly reviews the research background of DCLS and the development status of FEL at home and abroad, then states the significance of the successful research of this equipment, and finally highlights its application prospect.

free electron laser  /  extreme ultraviolet  /  Dalian Coherent Light Source  /  super flash