AUTHOR=Li Xiaohui , Song Zhuoying , Zhang Han , Song Yufeng , Panajotov Krassimir TITLE=Editorial: Ultrafast Photonics of Low-Dimensional Materials JOURNAL=Frontiers in Physics VOLUME=8 YEAR=2021 URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2020.632406 DOI=10.3389/fphy.2020.632406 ISSN=2296-424X