Broadband quasi-PT Symmetry Sustained by Inhomogeneous Broadening of the Spectral Line

Abstract

It is shown that inhomogeneous broadening of the spectral line of active impurities may sustain simultaneously parity (P) and time (T) symmetries of a medium, in a finite range of field frequencies, what is forbidden by the causality principle in media without broadening. If a spectral width of a propagating pulse is less than the inhomogeneous broadening, the medium for such a pulse becomes quasi-PT symmetric. The effect of the broadband quasi-PT symmetry in a finite frequency domain, is illustrated on examples of unidirectional diffraction of pulses in Bragg and Laue geometries, propagating in photonic crystals.

arXiv commentPhys. Rev. A (accepted); https://journals.aps.org/pra/accepted/ce070Y82C351455dd5b757a1abc23d0175d9d93a9; 9 pages, 5 figures

References in corpus (11)

• Real Spectra in Non-Hermitian Hamiltonians Having PT Symmetry
• Nonlinear waves in $\mathcal{P}\mathcal{T}$-symmetric systems
• Unidirectional Nonlinear PT-symmetric Optical Structures
• Physical realization of $\mathcal{P}\mathcal{T}$-symmetric potential scattering in a planar slab waveguide
• Anti-Parity-Time Symmetric Optics via Flying Atoms
• Exponentially Fragile PT-Symmetry in Lattices with Localized Eigenmodes
• Antisymmetric PT-photonic structures with balanced positive and negative index materials
• Zeno effect and switching of solitons in nonlinear couplers
• Causality and phase transitions in PT-symmetrical optical systems
• Giant amplification of modes in parity-time symmetric waveguides
• Bragg-induced power oscillations in PT symmetric periodic photonic structures