Biography
Dr. Zhaoyang Zhang
Dr. Zhaoyang Zhang
Xi’an Jiaotong University, China
Title: Coherent control on novel dynamic behaviors of light in electromagnetically induced photonic lattices
Abstract: 
Keywords: Electromagnetically induced transparency, Reconfigurable photonic lattices, Atomic coherence

Electromagnetically induced transparency (EIT) refers to the reduction of resonant absorption by quantum interference, so the medium becomes effectively transparent for the probe field (within a frequency width) under the action of a strong coherent (coupling) field on a linked transition. In the meanwhile, EIT can also greatly enhance and modulate the refractive index experienced by the probe field. With the intensity of the coupling field being spatially modulated in a periodic manner, the incident probe beam experience a periodically modified refractive index (indicating the formation photonic lattice) under the EIT condition. Owning to the immediate optical response of atomic medium to the modification on parameters operating EIT, such electromagnetically induced photonic lattices exhibit in situ tunability and reconfigurability.

Here, by taking advantages of the versatile nature of the coherently prepared multilevel atomic media, we experimentally demonstrate the novel dynamical behaviors of probe field travelling through spatially extended 1D and 2D electromagnetically induced photonic lattices established in coherently-prepared rubidium atomic vapors. The exhibited behaviors include parity-time symmetry breaking in a gain-loss waveguide array [1,2], evolution and interaction of optical vortices in wave packets aroud the Dirac point in photonic graphene [3,4], and nonlinear edge state in photonic graphene [5], ect.

References
[1] Z. Y. Zhang, et al. Observation of parity-time symmetry in optically induced atomic lattices, Phys. Rev. Lett. Vol. 117 (2016), p.123601
[2] Z. Y. Zhang, et al. Parity-time-symmetric optical lattice with alternating gain and loss atomic configurations, Laser Photon. Rev. Vol. 12 (2018), p.1800155
[3] Z. Y. Zhang, et al. Particlelike behavior of topological defects in linear wave packets in photonic graphene, Phys. Rev. Lett. Vol. 122 (2019), p. 233905
[4] Z. Y. Zhang, et al. Spin-orbit coupling in photonic graphene, Optica Vol. 7(2020), p.455.
[5] Z. Y. Zhang, et al. Observation of edge solitons in photonic graphene, Nat. Commun. Vol. 11 (2020), p. 1902.
Biography: 
Zhaoyang Zhang is a Professor in the School of Electronic Science and Engineering, Xi’an Jiaotong University, China. He has been engaged in the research of atomic physics, quantum optics, nonlinear optics, and optical properties of photonic lattices in multi-level atomic systems. Recently, he mainly works on novel dynamics of light in electromagnetically induced photonic lattices in atomic vapors. He is currently the Principle Investigator of National Nature Science Foundation for Excellent Young Scholars, and National Key Research & Development Project for Young Scientists, etc.