PT-symmetry in kagome photonic lattices

Journal Article · Mon Aug 28 00:00:00 EDT 2017 · Proceedings of SPIE - The International Society for Optical Engineering

DOI:https://doi.org/10.1117/12.2274503· OSTI ID:1565878

Chern, Gia-Wei ^[1]; Saxena, Avadh ^[2]

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1. Univ. of Virginia, Charlottesville, VA (United States). Dept. of Physics
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Photonic lattices composed of balanced gain and loss waveguides have attracted considerable attention due of their potential applications in optical beam engineering and image processing. These photonic lattices belong to a larger class of intriguing active metamaterials that exhibit the parity-time (PT) symmetry. Kagome lattice is a two-dimensional network of corner-sharing triangles and is often associated with geometrical frustration. In particular, the frustrated coupling between waveguide modes in a kagome array leads to a dispersionless flat band consisting of spatially localized modes. Recently, a PT-symmetric photonics lattice based on the kagome structure has been proposed by placing PT-symmetric dimers at the kagome lattice points. Each dimer corresponds to a pair of strongly coupled waveguides. With balanced arrangement of gain and loss on individual dimers, the system exhibits a PT-symmetric phase for finite gain/loss parameter up to a critical value. Here we discuss the linear and nonlinear optical beam propagations in this novel PT-symmetric kagome system. The linear beam evolution in this complex kagome waveguide array exhibits a novel oscillatory rotation of optical power along the propagation distance. Long-lived local chiral structures originating from the nearly flat bands of the kagome structure are observed when the lattice is subject to a narrow beam excitation. We further show that inclusion of Kerr-type nonlinearity leads to novel optical solitons.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Laboratory Directed Research and Development (LDRD) Program
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 1565878
• Report Number(s): LA-UR-17-27729; 1996-756X (Electronic)
• Journal Information: Proceedings of SPIE - The International Society for Optical Engineering, Vol. 10345; Conference: SPIE Nanoscience + Enginerring, San Diego, CA (United States), 6-10 Aug 2017; ISSN 0277-786X
• Publisher: SPIE
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
Atomic and Nuclear Physics
PT-symmetry
photonic lattice
kagome
beam dynamics
soliton