A universal form of arrays with spectral singularities

Abstract

An array of non-Hermitian optical waveguides can operate as a laser or as a coherent perfect absorber, which corresponds to a spectral singularity of the underlying discrete complex potential. We show that all lattice potentials with spectral singularities are characterized by the universal form of the gain-and-loss distribution. Using this result we systematically construct potentials characterized by several spectral singularities at arbitrary wavelengths, as well as potentials with second-order spectral singularities in their spectra. Higher-order spectral singularities demonstrate a greatly enhanced response to incident beams resulting in the excitation of high-intensity lasing modes.

accepted for Optics Letters

References in corpus (3)

• Coherent Perfect Absorbers: Time-reversed Lasers
• PT-symmetry breaking and laser-absorber modes in optical scattering systems
• A universal form of complex potentials with spectral singularities

Cited by in corpus (3)

• Pseudo-Hermiticity protects the energy-difference conservation in the scattering
• High-order spectral singularity
• Robust incoherent perfect absorption