Nonlinear beam deflection in photonic lattices with negative defects

Abstract

We demonstrate both theoretically and experimentally that a nonlinear beam can be reflected by a negative defect in a photonic lattice if the incident angle is below a threshold value. Above this threshold angle, the beam simply passes through the defect. This phenomenon occurs in both one-and two-dimensional photonic lattices, and it provides a way to use the incident angle to control beam propagation in a lattice network. If the defect is absent or positive, no evident transition from reflection to transmission occurs. These nonlinear phenomena are also compared with linear nondiffracting-beam propagation in a photonic lattice with a defect, and both similarities and differences are observed. In addition, some important features in linear and nonlinear beam propagations are explained analytically by using a linear model with a delta-function defect.

Defect induced wave-packet dynamics in linear one-dimensional photonic lattices

“…Linear defects in PLs originate from the change in the coupling between channels that form a defect which may be achieved either by modifying the distance between the channels or by changing the width of the channels [13][14][15][16]. The influence of nonlinear defects on light propagation in PLs is investigated in [16][17][18][19][20]. Wave propagation in periodic systems possessing both linear and nonlinear defects is studied [21,22] as well as scattering of linear and nonlinear waves in an array with a PT-symmetric defect [23].…”

Spatial storage of discrete dark solitons

“…Especially those concerning discrete optical systems, where there is a high flexibility to construct impurities by manipulating the relative refraction index between the impurities and the rest of the system [7]. In particular, it is possible to generate either positive or negative impurities with different resonance response [8]. Different impurities permit to control transmission, reflection or even the localization degree of energy [9].…”

Localized modes and dark solitons sustained by nonlinear defects

“…Focusing on continuous models (for a review on discrete systems see e.g. [5,6]), bright and dark solitons have been described in linear lattices with defects [7][8][9][10], in nonlinear lattices with linear defects [11,12], in media with periodically varying saturable nonlinearity in the presence of defects [13], in periodic media with a dissipative [14] and parity-time symmetric [15,16] defects, combined linear and nonlinear lattices [17,18], as well as at the interface between dissimilar nonlinear lattices [19]. Waves in pure nonlinear lattices (without defects) were also studied theoretically [20][21][22][23][24][25][26][27][28][29] and observed experimentally [30].…”