On May 20th, 2025, the State Administration for Market Regulation hosted the 2025 China's Major Event of "World Metrology Day" in Guangzhou. The event featured the announcement of the 2024 Science and Technology Progress Award of Chinese Society for Measurement, in which the "Cadmium Ion Microwave Clock Technology" project, led by our department, won the First Prize of the Science and Technology Progress Award. Associate Researcher Zhang Jianwei from the Department of Precision Instruments of Tsinghua University accepted the award on behalf of the team.

Accurate, stable, and uniform time and frequency measurements are of paramount importance in critical sectors such as defense, the Beidou satellite navigation system, financial transactions, power distribution networks, and telecommunications. At the heart of time and frequency metrology lies the atomic clock. However, the performance of traditional microwave atomic clocks falls short of the requirements for future high-performance timekeeping and synchronization systems. Ion trap microwave clocks, renowned for their exceptional stability and precision, have emerged as the next generation of high-end microwave atomic clock technology that nations are vying to develop. The "Cadmium Ion Microwave Clock Technology" project, spearheaded by Tsinghua University in partnership with the 203rd Institute of the Second Academy of China Aerospace Science and Industry Corporation, has received support from major national initiatives, including the National Key Research and Development Program. This project has concentrated on achieving key technological advancements for the next generation of high-performance microwave atomic clocks that are both accurate and stable. It has pioneered a "laser cooling + cadmium ion" microwave clock approach, leading to the successful development of the world's first prototype of a laser-cooled cadmium ion microwave clock. This prototype boasts a frequency stability of 1.4E-13@1s and 1.7E-14@1000s, with a frequency uncertainty surpassing 1.8E-14, positioning it at the forefront of international developments in similar microwave atomic clocks. The project's accomplishments have been implemented in esteemed institutions such as the National Institute of Metrology and the China Aerospace Science and Technology Corporation, where they have played a pivotal role in several significant national scientific research endeavors.

The core team for the awarded project is the Time and Space Reference Team from the Department of Precision Instruments at Tsinghua University, with Professor Wang Lijun as the team leader and Associate Researcher Zhang Jianwei, a key member of the team, being the first accomplisher of the project. In line with precision measurement science and technology, the Time and Space Reference Team conducts research on large-scale time-space measurement and real-time positioning technologies, with a particular focus on areas such as high-performance atomic clocks, time-frequency synchronization and applications based on optical fibers and satellites, absolute gravimeters, and atomic magnetometers. The team addresses significant national strategic demands and has taken the lead in undertaking multiple national-level scientific research tasks, including projects under the National Key R&D Program of the Ministry of Science and Technology, major instrument-specific projects of the National Natural Science Foundation of China, major breakthrough projects of the Ministry of Science and Technology, and defense-related science and technology projects.

The "Science and Technology Progress Award of Chinese Society for Measurement" is a comprehensive award established by the Chinese Society for Measurement and registered with the National Office for Science and Technology Awards. It is aimed at the national metrology field (industry) and represents the highest level of scientific and technological achievements in the national metrology field (industry). After the stages of online preliminary review, meeting review, final review by the evaluation committee, and public announcement, the 2024 Science and Technology Progress Award of Chinese Society for Measurement has recognized a total of 26 award-winning achievements, encompassing 5 first prizes and 1 third prize in the basic research category; and 5 first prizes, 8 second prizes, and 7 third prizes in the applied research category. The "Cadmium Ion Microwave Clock Technology" project, for which our university won an award, was primarily completed by: Zhang Jianwei, Wang Lijun, Zuo Yani, Miao Shengnan, Chen Yiting, Zheng Ying, Xue Xiaobo, Zhang Shengkang, Shi Wenxin, Chen Shuotian.