Choi Youngsun, Hong Jong-Kyun, Cho Jin-Ho, Lee Kwang-Geol, Yoon Jae Woong, Song Seok Ho
Opt Express. 2015 May 4;23(9):11783-9. doi: 10.1364/OE.23.011783.
We theoretically demonstrate spontaneous PT-symmetry breaking behavior of surface-plasmon polaritons (SPP) in coupled double-slab (DS) waveguides. By virtue of a flat-top field at critical wavelength, the imaginary index of a DS-SPP mode can be controlled via changing the core thickness, while the real index is kept constant. Therefore, a waveguide coupler that consists of a pair of DS-SPP waveguides with different core thicknesses can represent a passive PT-symmetric system, which always maintains symmetry under a real potential. This set-up also represents a good opportunity to investigate the underlying physics of PT-symmetry breaking in non-Hermitian Hamiltonian systems.
我们从理论上证明了耦合双平板（DS）波导中表面等离激元极化激元（SPP）的自发宇称时间（PT）对称性破缺行为。借助临界波长处的平顶场，通过改变芯层厚度可以控制DS-SPP模式的虚部折射率，而实部折射率保持不变。因此，由一对具有不同芯层厚度的DS-SPP波导组成的波导耦合器可以表示一个无源PT对称系统，该系统在实势下始终保持对称性。这种设置也为研究非厄米哈密顿系统中PT对称性破缺的潜在物理机制提供了一个很好的机会。
