The Thin Film Optics Laboratory of the Institute of Optoelectronic Technology, Chinese Academy of Sciences has made progress in the fabrication of low defect density infrared thin films. By optimizing the coating process of infrared thin films, the defect density of the ZnS/SrF multilayer films is significantly reduced. The defect of infrared film is an important factor affecting the optical properties of infrared film and its stability. It has been concerned by researchers at home and abroad. The Optoelectronics Research Institute has significantly reduced the defects of multi-layer infrared films by optimizing deposition deposition rate, deposition temperature, and deposition method: The defect density of multi-layer infrared films has been reduced by an order of magnitude. The 164nm high reflective film prepared with low defect density process parameters has a reflectance of greater than 99.9% and an absorption of less than 100 ppm. Par56 Pool Light,led udnerwater light,PAR56 swimming pool light Shenzhen Poolux Lighting Co., Ltd. , https://www.pooluxled.com