Anti-parity-time symmetry enabled on-chip chiral polarizer

Anti-parity-time symmetry, often abbreviated as Anti-PT symmetry, is a concept that has been explored in various physical systems, including optics and atomic systems. This concept involves the breaking of parity-symmetry, which is the symmetry with respect to spatial inversion, and time-symmetry, which is the symmetry with respect to time reversal. The implementation of Anti-PT symmetry has been shown to lead to unique quantum phenomena and has potential applications in precision sensing and the development of unidirectional optical devices such as optical switches and isolators125.

Recently, there has been a significant development in the field where an experimental realization of an optical Hamiltonian with Anti-PT symmetry has been achieved3. This breakthrough was a collaborative effort with the theoretical team from Yale University, led by Professor Liang Jiang and Dr. Jianming Wen. The experiment involved the use of a system with low thermal conductivity and thermal coupling, where two counter-rotating parallel rings were used to demonstrate the Anti-PT symmetry condition at relatively low rotation speeds, resulting in a stable thermal field distribution6.

The team led by Professor Xuefeng Zhu from Huazhong University of Science and Technology confirmed the existence of Anti-PT symmetry7. Furthermore, on April 19, a joint team of Professor Zhu and Professor Li Ying from Zhejiang University achieved parity-time symmetry in diffusive systems for the first time, with their findings published in the journal Science under the title "Observation of parity-time symmetry in diffusive systems"8.

The implications of these findings are profound, particularly for the development of on-chip chiral polarizers. Chiral polarizers are devices that can selectively transmit light of a specific handedness or polarization state. The introduction of Anti-PT symmetry could enable the creation of on-chip devices that exhibit unique optical properties, such as the ability to control the directionality of light propagation, which is crucial for integrated photonic circuits and other advanced optical applications9.

In summary, the advent of Anti-PT symmetry in physical systems has opened up new avenues for research and technological development, particularly in the realm of on-chip optical devices, where the control of light at the nanoscale is of paramount importance.