Enhanced Frequency Conversion in Parity-Time Symmetry Line
Abstract
Non-Hermitian degeneracies reveal intriguing and non-trivial behaviors in open physical systems. Examples like Parity-Time (PT) symmetry breaking, topological encircling chirality, and enhanced sensing near an exceptional point (EP) are often associated with the abrupt nature of the phase transition around these degeneracies. Here we experimentally observe a cavity-enhanced second-harmonic frequency (SHG) conversion on a PT symmetry line, i.e. a set consisting of open-ended isofrequency or isoloss lines, both terminated at EPs on the Riemann surface in parameter space. The enhancement factor can reach as high as 300, depending on the crossing point whether in the symmetry or the broken phase of the PT line. Moreover, such enhancement of SHG enables sensitive distance sensing with a nanometer resolution. Our works may pave the way for practical applications in sensing, frequency conversion, and coherent wave control.
Cite
@article{arxiv.2402.06200,
title = {Enhanced Frequency Conversion in Parity-Time Symmetry Line},
author = {Jiankun Hou and Jiefu Zhu and Ruixin Ma and Boyi Xue and Yicheng Zhu and Jintian Lin and Xiaoshun Jiang and Yuanlin Zheng and Xianfeng Chen and Ya Cheng and Li Ge and Wenjie Wan},
journal= {arXiv preprint arXiv:2402.06200},
year = {2024}
}