Supersymmetry Laser Arrays with High‐Order Exceptional Point

Abstract

Supersymmetry (SUSY) laser array with superpartner structure can suppress excess modes to achieve high‐intensity and high‐coherent radiation. Compared with complex superpartner, using parity time (PT) symmetry broken to manipulate SUSY laser arrays is a more flexible approach. Herein, based on ultrathin perovskite single crystal, a SUSY laser array is constructed without superpartner, but with auxiliary gain–loss structure. PT symmetry broken with high‐order exceptional point (EP) is realized in the visible spectral range. It intrinsically avoids superpartner field mismatch and improves side mode suppression ratio 8.8–12 dB for single‐mode lasing. Furthermore, variations in EP‐order enable the transition from single‐mode to dual‐mode or tri‐mode radiation and retain amplified radiation characteristics. In addition, these SUSY laser arrays with the high‐order EP have the potential to be small‐volume optical sensor devices. The new design combining SUSY and PT symmetry broken presents its potential in micro‐nanophotonic devices with the benefit of small size, flexibility in spectral control, expandability, simplicity, and multifunctionality feature.

Optical ladder operators in the Glauber-Fock oscillator array

“…Besides, due to the formal equivalence between the Schrödinger equation and the paraxial Helmholtz equation [21] (also between the stationary Schrödinger equation and the Helmholtz equation), optical waveguides are suitable devices to observe, study and test quantum phenomena [22]. Therefore, either isolated waveguides or waveguide arrays (optical lattices), are susceptible to be transformed by means of Darboux or SUSY transformations [23][24][25][26][27][28][29][30][31][32][33][34], in the Hermitian [26][27][28][31][32][33][34] and non-Hermitian [9,10,[23][24][25][28][29][30] regimes. Specifically, an optical lattice associated with a Hamiltonian of the type of the quantum harmonic oscillator can be 'intertwined' with itself, giving rise to the ladder of supermodes (eigenstates) [35,36].…”