Orbital angular momentum complex spectrum analyzer for vortex light based on the rotational Doppler effect

• 来源期刊: 光：科学与应用（英文版）
• 关键词: mode analysis orbital angular momentum rotational Doppler effect
• 年，卷（期）: 2017,（2）
• 页码范围: 119-126
• 页数: 8页
• 语种: 英文
• DOI: 10.1038/lsa.2016.251

摘要

The ability to measure the orbital angular momentum (OAM) distribution of vortex light is essential for OAM applications.Although there have been many studies on the measurement of OAM modes,it is difficult to quantitatively and instantaneously measure the power distribution among different OAM modes,let alone measure the phase distribution among them.In this work,we propose an OAM complex spectrum analyzer that enables simultaneous measurements of the power and phase distributions of OAM modes by employing the rotational Doppler effect.The original OAM mode distribution is mapped to an electrical spectrum of beat signals using a photodetector.The power and phase distributions of superimposed OAM beams are successfully retrieved by analyzing the electrical spectrum.We also extend the measurement technique to other spatial modes,such as linear polarization modes.These results represent a new landmark in spatial mode analysis and show great potential for applications in OAM-based systems and optical communication systems with mode-division multiplexing.