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A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
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Circularly Polarized States Spawning from Bound States in the Continuum
Wenzhe Liu1,2, Bo Wang1,2, Yiwen Zhang1,2
1State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonic Structures (Ministry of Education) and Department of Physics, Fudan University, Shanghai 200433, China.
Physical Review Letters
|October 2, 2019
Summary
Periodic photonic systems exhibit vortex polarization singularities. Breaking C2 symmetry in photonic crystal slabs creates circularly polarized states, enabling full Poincaré sphere coverage for advanced polarization manipulation and topological photonics applications.
Area of Science:
- Topological photonics
- Condensed matter physics
- Optical physics
Background:
- Bound states in the continuum (BICs) in periodic photonic systems are linked to vortex polarization singularities in momentum space.
- These polarization structures offer potential for advanced polarization manipulation and topological physics.
Purpose of the Study:
- To investigate the emergence of circularly polarized states from BICs by breaking in-plane inversion (C2) symmetry.
- To demonstrate full Poincaré sphere coverage and explore applications in polarization modulation.
Main Methods:
- Breaking the C2 symmetry of photonic crystal slabs.
- Analyzing the resulting photonic bands and polarization states in momentum space.
- Demonstrating ellipticity modulation of linear polarization in the visible frequency range.
Main Results:
- Pairs of circularly polarized states emerge from eliminated BICs upon C2 symmetry breaking.
- Full coverage of the Poincaré sphere is achieved with circularly and linearly polarized states.
- Ellipticity modulation of linear polarization is successfully demonstrated.
Conclusions:
- C2 symmetry breaking in photonic systems provides a novel pathway to generate and control polarization states.
- The findings open new avenues for applications in polarization manipulating devices, light-matter interactions, and topological photonics.
- Further exploration of these polarization singularities could uncover new physics in radiation modulation.
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