The ultra-stable optical reference cavity with high finesse is the key to the development of narrow linewidth lasers, which also is one of the core technologies in the scientific application platform of China Space Station. 

     Recently a joint research group led by Dr. Tao Liu at NTSC developed a high-finesse spherical optical reference cavity for space environment application which is an important breakthrough for the independent development space narrow linewidth lasers.  

     They have mastered the key technologies in manufacturing ultra-stable optical reference cavities such as ultra-precision optical manufacture, ultra-high reflectivity coating and non-adhesive optical bonding. 

     The measurement results show that the loss of the spherical ultra-stable optical reference cavity with a fineness of ~200000 is less than 5ppm and the mirror reflectivity is 0.9999914. These index parameters are equal to that of imported products, which meet the urgent need of scientific application in China Space Station. This work is published in Acta Physica Sinica No. 8, 2017. The reviewer argues that the study is a very difficult and challenging task and has a sense of breaking the potential embargo against our country. 

     This research is supported by the development of major national scientific research equipment and the National Natural Science Foundation of China.