University of Central Florida physicist Zenghu Chang has done it again. For a third time this year, his research group has published an article in a Nature journal.
This time, Chang and his team have developed a new ultrafast light source for observing electron motion in molecules 麻豆精品 S� made up of nuclei and electrons 麻豆精品 S� at the point before the nuclei start to move. By being able to observe what actually happens, scientists can begin to understand how an electron interacts with other electrons, which may help improve the efficiency of solar cells.
麻豆精品 S淭he charge migration that theorists have been predicting since 1999 happens so quickly we haven 麻豆精品 S檛 been able to observe it yet, 麻豆精品 S� Chang said. 麻豆精品 S淚t 麻豆精品 S檚 very exciting, because we have found a new way to build light sources that may allow us to see it in the future. 麻豆精品 S�
Being able to see this superfast interaction between electrons gives scientists another tool to unlock the rules that govern the quantum-mechanics world 麻豆精品 S� a world where microscopic objects don 麻豆精品 S檛 obey the laws of physics we have come to rely on for understanding in the macro world.
So how did Chang and his team manage to develop the new light source? The team borrowed an idea from Chang 麻豆精品 S檚 earlier innovative work in the area of ultrafast lasers.
麻豆精品 S淲e control the below-threshold harmonic light emission by using electromagnetic fields with time-dependent ellipticity, like we have done to the above-threshold high-order harmonics, 麻豆精品 S� said Chang referring to the creation of a 67-attosecond pulse of extreme ultraviolet light, which earned him international recognition.聽 麻豆精品 S淲e thought: Could we use the same gating fields to show the dependence of the below-threshold harmonic intensity on the carrier-envelope phase of the driving laser? It took us some time to find the right experimental parameters, but the answer is yes. 麻豆精品 S�
The result of his study 麻豆精品 S淐oherent phase-matched VUV generation by field-controlled bound states 麻豆精品 S� appears this week in .
Chang has been studying light and ultrafast lasers his entire career. This past year UCF established the Institute for the Frontier of Attosecond Science and Technology (FAST). The institute is a collaboration between experts and students in UCF 麻豆精品 S檚 College of Optics and Photonics (CREOL) and the College of Sciences 麻豆精品 S� physics department to focus on this field of science. Chang has a joint appointment in CREOL.
Co-authors include: Michael Chini, Xiaowei Wang, Yan Cheng, Yi Wu and Eric Cunningham from UCF 麻豆精品 S檚 FAST; Peng-Cheng Li, John Heslar and Shih-I Chu from the Center for Quantum Science and Engineering and the Department of Physics at the National Taiwan University; He Wang from the Materials Sciences Division at the Lawrence Berkeley National Laboratory, and Dmitry A. Telnovfrom the Department of Physics at St. Petersburg State University in Russia.
麻豆精品 S淚t was truly a collaborative effort, 麻豆精品 S� Chang said. 麻豆精品 S淎nd there are certainly commercial applications. We 麻豆精品 S檙e talking about cutting-edge lasers with potential application in electronics, navigation, communications and medicine. 麻豆精品 S�
Chang said he is excited about the new work because he hopes it will help lead to bigger and greater discoveries.
To see other 2014 Nature Photonics articles click here and here .
麻豆精品 S淢y dream is to discover new physics that has not been predicted at this time, 麻豆精品 S� Chang said. 麻豆精品 S淯ntil there was a microscope, we had no idea how complicated, how amazing cells were. What we are creating now are tools for magnifying time in order to discover what we have not even imagined yet. That 麻豆精品 S檚 what I see for the future of our field. 麻豆精品 S�
The Defense Advanced Research Projects Agency, National Science Foundation, U.S. Department of Energy, National Science Council of Taiwan and National Taiwan University funded the research.