Ahmed Hassan Zewail (born February 26, 1946) is an Egyptian scientist, known as the "father of femtochemistry", he won the 1999 Nobel Prize in Chemistry for his work on femtochemistry and became the first Egyptian scientist to win a Nobel Prize in a scientific field. He is the Linus Pauling Chair Professor of Chemistry, Professor of Physics, and the director of the Physical Biology Centre for Ultrafast Science and Technology (UST) at the California Institute of Technology.He received Davy Medal in 2011 for his seminal contributions to the study of ultrafast reactions and the understanding of transition states in chemistry, and to dynamic electron microscopy.