After receiving his doctoral degree in optics, Gaeta remained at the University of Rochester for two years as a postdoctoral research associate. He joined the Cornell faculty in 1992. He received Young Investigator Awards from the Office of Naval Research in 1993, and from the Army Research Office in 1995. He was a recipient of the College of Engineering Teaching Award in 1997, 2000, 2003, and 2007. He is a fellow of the Optical Society of America and of the American Physical Society. Gaeta has served as director of the Center for Nanoscale Systems from 2007-2012.
His research interests include ultrafast nonlinear optics, nanophotonics, nonlinear propagation in fibers and bulk media, photonic crystal fibers, coherent interactions of laser light with matter, the generation of non-classical light fields, stimulated scattering processes.