Eur. Phys. J. D (2016) 70: 14
https://doi.org/10.1140/epjd/e2015-60434-7

Regular Article

Multihump solitons in two-dimensional parity-time-symmetric optical lattices with focusing saturable nonlinearity

¹ Department of Physics, Guangdong University of Education, Guangzhou 510303, P.R. China
² State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, P.R. China

^a e-mail: lihuagang@gdei.edu.cn

Received: 25 July 2015
Received in final form: 1 December 2015
Published online: 19 January 2016

Abstract

We study the existence and stability of multihump solitons in two-dimensional (2D) parity-time (PT)-symmetric periodic potentials with focusing saturable nonlinearity. All the humps of these solitons are in consecutive lattice sites and the adjacent two humps are out-of-phase. These multihump solitons exist in finite regions in the semi-infinite gap and cannot bifurcate from the edge of the first Bloch band. They can be stable in the moderate power region. It is found that the saturation parameter will affect the existence and stability of these multihump gap solitons significantly. The transverse power flow vector in these 2D multihump solitons in focusing saturable media is also investigated.