Regular Article

Singular pole and enhanced sensitivity of PT-symmetric layered structure with resonators

School of Computer Science and Communication Engineering, Jiangsu University, Zhenjiang 212013, PR China

^* e-mail: fang_yt1965@sina.com

Received: 3 May 2018
Received in final form: 29 July 2018
Accepted: 19 September 2018
Published online: 16 November 2018

Abstract

In order to achieve enhanced transmittance of parity-time (PT)-symmetric system, we design a layered PT-symmetric structure including resonators. We use the scatter matrix method to study the optical properties of the designed structure under the modulation of resonators. The structure system takes on a singular pole effect, i.e., the huge reflectance and transmittance occur at a special wavelength and period number. The field distribution reveals that the singular pole results from the coupling resonance of single cavity and the whole structure. Because of the coupling resonance, the total gain in layer A is much larger than the total loss in layer C. The reflectance and transmittance at the singular pole take on a high sensitivity on the refraction index of the resonators.