Observation of diffraction pattern in two-dimensional optically induced atomic lattice

The diffraction pattern of a two-dimensional optically induced atomic lattice is reported experimentally in a three-level atomic system. Such a two-dimensional optical lattice is established by two orthogonal standing-wave fields induced by the interference of two pairs of coupling laser beams. When the probe beam is launched into it, a spatially modulated discrete diffraction pattern can be obtained at the output plane of the vapor cell under the electromagnetically induced transparency condition. We investigate the diffraction pattern under different experimental parameters and find that it can be effectively controlled by tuning the coupling laser power and two-photon detuning. Our work may potentially pave the way for studying the control of light and other intriguing physical phenomena based on such a periodically modulated atomic lattice. (C) 2019 Optical Society of America