Propagation of Partially Coherent Light in non-Hermitian Lattices

Abstract

Band theory for partially coherent light is introduced by using the formalism of second-order classical coherence theory under paraxial approximation. It is demonstrated that the cross-spectral density function, describing correlations between pairs of points in the field, can have bands and gaps and form a correlation band structure. The propagation of a partially coherent beam in non-Hermitian periodic structures is considered to elucidate the interplay between the degree of coherence and the gain/loss present in the lattice. We apply the formalism to study partially coherent Bloch oscillations in lattices having parity-time symmetry and demonstrate that the oscillations can be sustained in such media but they are strongly dependent upon the spatial correlations of the beam. A transition between breathing and oscillating modes is shown to be induced by the degree of spatial coherence.

References in corpus (9)

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• Probing topological invariants in the bulk of a non-Hermitian optical system
• Spectral and transport properties of time-periodic PT-symmetric tight-binding lattices
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• Scattering theory for stationary materials with $\mathcal{P}\mathcal{T}$ symmetry
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• Light scattering from stationary $\mathcal{P}\mathcal{T}$-symmetric collections of particles
• Low coherence-induced resonance in double-layer structures having parity-time symmetry