Abstract
Conference Title: 2014 39th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz) Conference Start Date: 2014, Sept. 14 Conference End Date: 2014, Sept. 19 Conference Location: Tucson, AZ, USA We develop a density-matrix formalism in the length gauge to simulate the nonlinear response on undoped graphene at terahertz frequencies. The generation of high harmonics is controlled by the strong interplay between intraband and interband dynamics. We present the differential signal, which reveals clear evidence of the high harmonic generation.