The ability to dynamically control the nonlinear phase in optical systems is crucial. It improves flexibility, adaptability, and functionality across a wide range of applications, from telecommunications and quantum computing to imaging and adaptive optics. However, despite the widespread interest in ferroelectric crystals and metasurfaces for their potential to manipulate the nonlinear phase of light, two major challenges remain: complex and energy-intensive fabrication processes, and the limitations of static optical systems with fixed properties once constructed.
In a new paper published in Light: Science & Applications, a team of scientists led by Assistant Professor Ling-Ling Ma and Professor Yan-Qing Lu from National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, Nanjing University, China, along with colleagues, introduced a new approach utilizing nonlinear Pancharatnam-Berry ferroelectric nematics. They provide an intuitive representation of the linear and nonlinear Pancharatnam-Berry phase shift in LCs, governed by the orientation angle of the medium's anisotropic structure and the spin state of the incident light. They summarize the proposed reconfigurable nonlinear Pancharatnam-Berry LCs:
"Our ion-doped FNLC devices exhibited large-area, defect-free polarization patterns, ensuring robust and reproducible optical performance. This scalability is critical for practical applications, as it ensures that the proposed approach can be extended to larger-scale systems."
"The ability to dynamically control the in-plane orientation of polar LCs with low electric fields (0.06 V/μm) enables real-time, continuous adjustment of the nonlinear Pancharatnam-Berry phase imparted to the generated nonlinear beam through geometric rotations."
"We demonstrate both theoretically and experimentally the precise and reconfigurable steering of second harmonic signals, including dynamic control over diffraction orders, intensity patterns, and polarization states, paving the way for future advanced nonlinear photonic devices."
This study marks an important advancement in nonlinear optics by demonstrating the feasibility of using ion-doped FNLCs as a platform for reconfigurable nonlinear Pancharatnam-Berry LC optics. Potential applications include advanced optical processing, adaptive optics, and quantum information technologies. The dynamic tunability of the nonlinear Pancharatnam-Berry phase in FNLCs offers unprecedented flexibility in manipulating light-matter interactions. The ability to continuously modulate SHG signals via electrically controlled splay conditions makes this platform highly versatile for various optical tasks. Furthermore, the scalability of the approach ensures that these devices can be integrated into practical systems, bridging the gap between fundamental research and real-world applications.
