Phase diagram of La2-xSrxCuO4 probed in the infared: imprints of charge stripe excitations.

While there is increasing evidence for antiferromagnetic (AF) ordering in the Cu-O planes of high-T(c) superconductors, either static or fluctuating, there is no direct evidence so far for the charge stripes that should separate the AF domains. By investigating the optical response of La2-xSrxCuO4 for 0<or=x<or=0.26 and 30<or=T<or=295 K, we identify strong far infrared peaks whose energy, width, and intensity are consistent with a scenario of charge stripe dynamics in the Cu-O planes.