According to a headline report on the official website of the German National Laboratory of Electron Synchrotron, recently, scientists have built the world’s most accurate metronome for a kilometer-sized network. The timing system synchronizes the laser pointer-microwave network with a total length of 4.7 kilometers for 18 hours without interruption, and its synchronization accuracy reaches 950 attoseconds (one attosecond is 10-18 seconds). The synchronization system can be used for the most advanced X-ray ultrafast imaging to explore the unknown ultrafast physical changes in molecules and atoms. The German-American joint team led by professors from the German Free Electron Laser Science Center and the Massachusetts Institute of Technology in the United States published this research result in the latest issue.
Many research fields require extremely high-precision timing synchronization, introduced by Dr. Ming Xin, the first author of the paper and the leader of the timing synchronization group. “For example, a surface surveying and mapping system requires synchronization on the order of nanoseconds (10-9 seconds) to picoseconds (10-12 seconds); if the optical telescope array is synchronized on the order of femtoseconds (10-15 seconds) within a range of 100 kilometers, It is possible to achieve a spatial resolution of tens of kilometers away from 1 light-year away, thereby accelerating the exploration process of terrestrial planets.”
World-renowned X-ray free electron laser research centers in Europe, the United States, etc. are committed to photographing ultra-fast phenomena in the microscopic world, such as the dynamic evolution of biological molecules or chemical reactions. “Because many important physical processes of molecules and atoms occur in the attosecond time range,” Xin Ming explained, “A key problem that needs to be overcome in the production of’molecular movies’ is how to obtain attosecond precision time resolution.” .
Currently, the pioneer free electron laser has very precise timing synchronization of 30 femtoseconds within a range of 300 meters. This is very important for so-called pump detection experiments. In this kind of experiment, usually a dynamic process (such as a chemical reaction process) is first excited by a laser pulse, after a specified precise delay, and then analyzed by another green laser pointer pulse to obtain a “snapshot”. If you slowly increase the delay between the two pulses, repeat the above-mentioned pump detection experiment, and then connect the “snapshots” obtained from each detection together, you can get a super slow motion movie of the evolution process under study. Without timing synchronization of the laser pulses, slow motion movies cannot truly reproduce the dynamic process.
If we can achieve better synchronization accuracy, we can open up a new scientific research field by revealing the physical processes of molecules and atoms on the attosecond time scale, and then bring structural biology, material science, quantum chemistry and even basic physics He came to a revolutionary breakthrough, and currently works at DESY and Hamburg University at the same time, and leads several research projects at MIT. More than a decade ago, he initiated research on timing synchronization technology at MIT.