Affiliation:
1. National Laboratory of Solid State Microstructures Key Laboratory of Intelligent Optical Sensing and Manipulation College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 China
2. Department of Electrical and Computer Engineering National University of Singapore Singapore 117583 Singapore
3. Department of Physics Nantong University Nantong 226019 China
Abstract
AbstractLinear conformal transformation provides an effective way to detect orbital angular momentum (OAM) of photons, and particularly, their coherent superposition states that are significant for OAM‐based technologies. However, these methods have limited applicability—they are applied to single or few separated wavelengths and cannot achieve nondestructive detection—although those features are attractive for practical applications. Here, the second‐harmonic spiral transformation is theoretically described and experimentally demonstrated through IR‐visible detection of OAM states from 900 to 1400 nm, with a low energy loss of ≈10−6. Remarkably, a record high optical finesse of ≈5.52 is predicted and observed, indicating that a nonlinear enhancement factor resulting from OAM conservation significantly improves separation efficiency. Additionally, this scheme allows flexibility to achieve lower energy losses or higher sensitivity by adjusting phase‐matching conditions. These results can be applicable to classical and quantum areas and promote conformal transformation into nonlinear regions.
Subject
Condensed Matter Physics,Atomic and Molecular Physics, and Optics,Electronic, Optical and Magnetic Materials