At the invitation of National Time Service Center (NTSC), Prof. Dr. Karl Ulrich Schreiber, a distinguished scientist in the field of large ring laser gyroscope (RLG) from Technische Universitaet Muenchen, visited NTSC recently. Prof. Schreiber was conferred as a guest professor by the NTSC, and the potential international cooperation on the universal time (UT1) measurement was proposed.

In the morning, the meeting started with a brief introduction to Dr. Schreiber, then, followed with the guest professor appointment ceremony. In this ceremony, Prof. Zhang Shougang, the director of NTSC, issued letters of appointment to Dr. Schreiber as a visiting professor of NTSC. Afterwards, Prof. Schreiber gave a talk on the topic of "Large Ring Laser Technology", in which he introduced the current research status of large Sagnac interferometry and the latest progress of their large ring laser gyroscopes. With 30 years’ persistently and thoroughly studies, Prof. Schreiber has built the world-record precise “G” ring, which provides a unique method with high precision for the application of universal time, space reference system, Lense-Thirring effect, etc. In the discussion section, Prof. Schreiber answered the related technical problems and future applications of large scale ring laser gyroscopes to the participants with great patient. 

After the presentation, Prof. Schreiber visited the cesium atomic fountain clock, strontium optical clock, optical gyroscope and other laboratories. He has a comprehensive and better understanding of the quantum time and universal time research activities at the NTSC, and interested in cooperation with NTSC on the precision measurement of the UT1.