Phys.org August 8, 2023
Orbital angular momentum (OAM) spectrum diagnosis is a fundamental building block for diverse OAM-based systems. Among others, the simple on-axis interferometric measurement can retrieve the amplitude and phase information of complex OAM spectra in a few shots. Yet, its single-shot retrieval remains elusive, due to the signal–signal beat interference inherent in the measurement. Researchers in Switzerland have introduced the concept of Kramers–Kronig (KK) receiver in coherent communications to the OAM domain, enabling rigorous, single-shot OAM spectrum measurement. They explained in detail the working principle and the requirement of the KK method and applied the technique to precisely measure various characteristic OAM states. They discussed the effects of the carrier-to-signal power ratio and the number of sampling points essential for rigorous retrieval and evaluate the performance on a large set of random OAM spectra and high-dimensional spaces. According to the researchers single-shot KK interferometry shows enormous potential for characterizing complex OAM states in real time… read more. Open Access TECHNICAL ARTICLE
On-axis Kramers-Kronig interferometry retrieves the spectrum of orbital angular momentum in a single-shot. Credit: Advanced Photonics (2023)Â