reporter learned from of the Chinese Academy of Sciences that my country's scientific research team has implemented a high-precision time frequency transmission experiment of free space of 100 kilometers for the first time in the world. The time transmission stability reaches the order of femtosecond (one trillionth of a second), and the frequency transmission stability is better than 4E-19 (equivalent to the error of about 100 billion years of the clock, which can meet the current time transmission requirements of the highest accuracy light clock .
This study was completed by the team of Academician Pan Jianwei of the University of Science and Technology of China and several cooperative units. The relevant results were published online in the international academic journal Nature on October 5.
00 kilometers high-precision time-frequency transmission experiment diagram. (Photo provided by the research team)
In recent years, the stability of the light clock has entered the E-19 order, and will form a new generation of time frequency standards (optical frequency standards), which can play an important role in the fields of precision navigation and positioning, global timing, wide-area quantum communication , and basic principles inspection of physics.
"Accurate timing should not be limited to cold laboratories, but should also 'fly into the homes of ordinary people'. Building a wide-area optical frequency standard network through high-precision time frequency transmission is the prerequisite for the optical clock to play a role in many of the above fields." Shen Qi, the first author of the article and an associate researcher at the University of Science and Technology of China, said that there should be time transmission technology that matches the accuracy of the optical clock to spread the precise time.
According to reports, free space high-precision time-frequency transmission is an important part of establishing a global wide-area optical frequency standard network, but previous international related research results have low signal-to-noise ratio and close transmission distance, making it difficult to meet the needs of high-precision time-frequency transmission of satellite-ground links.
In this study, the research team realized a high-stable optical frequency comb with watt-level power output, realizing high-sensitivity linear optical sampling detection of the order of nanowatts, further improving the stability and reception efficiency of the optical transmission telescope. Based on the above technological breakthroughs, the research team successfully achieved time-frequency transmission of 113 kilometers of free space in Urumqi, Xinjiang, fully verified the feasibility of high-precision optical frequency standard comparison of the satellite-ground link. More than
html reviewers from Nature magazine said that this study is a major breakthrough in the field of long-distance optical time frequency transmission in free space of satellites and ground, and will have an important impact on basic physics research such as dark matter detection, basic physics constant test, and relativity test.Source: Xinhua News Agency
