January 2022
Spotlight Summary by Alex Krasnok
Anti-parity-time symmetry enabled on-chip chiral polarizer
The physics of non-Hermitian open physical systems offers new interaction schemes and applications to a great extent enabled by topological properties of exceptional points (EPs). Yanxian Wei et al. propose and experimentally demonstrate a chiral polarizer in an anti-PT symmetric system, forming different polarized states dependent on light propagation direction. Although efficient polarizers are crucial for modern integrated photonics on a chip, the conventional designs cause losses and energy consumption by rejecting undesired polarization. The proposed approach, in contrast, utilizes the mode polarisation conversion during adiabatic and not adiabatic evolution of the system around the EP, an effect known for a while but now wisely implemented for superb on-chip optical polarizers. Specifically, the experimentally implemented system demonstrates a polarization extinction ratio of 10 dB between the transmission of TE and TM modes over a bandwidth from 1550 to 1590 nm. In addition to its potential for practical application, the broad idea that underpins this work is fascinating from a fundamental perspective: utilizing topologically nontrivial states with the geometric Berry phase for on-chip photonics. The further development of the approach is possible exploring other geometries, for example, coupled microring resonators and utilizing higher-order exceptional points.
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Article Information
Anti-parity-time symmetry enabled on-chip chiral polarizer
Yanxian Wei, Hailong Zhou, Yuntian Chen, Yunhong Ding, Jianji Dong, and Xinliang Zhang
Photon. Res. 10(1) 76-83 (2022) View: Abstract | HTML | PDF