On-Chip Photon Angular Momentum Absolute Measurement Based on Angle Detection

Photon angular momentum (AM) has been widely studied due to its unique properties. The accurate detection of photon AM is very important in its wide applications. Though various on-chip AM detectors based on surface plasmon polaritons (SPPs) have been proposed, most of them can only realize relative measurement. For example, most photon orbital angular momentum (OAM) detectors measure the high order OAM via measuring the relative interval between the intensity spots of the SPPs excited by the target order OAM beam and the reference order (usually 0th order) OAM beam. In this paper, we propose a simple on-chip photon AM detector. It can realize absolute measurement of photon OAM via angle detection, whose measurement result does not depend on the measurement of any reference OAM beam. At the same time, it can also recognize photon spin angular momentum (SAM). The proposed detector provides a new way for absolute measurement of photon AM, which may have some potential applications in the field of integrated photonic device.

Automated summary

Photon angular momentum plays a crucial role in various applications, and accurate measurement of photon angular momentum is of great importance. However, most on-chip detectors can only achieve relative measurement and rely on the measurement of reference beams. In this paper, a simple on-chip detector is proposed, which can achieve absolute measurement of photon angular momentum through angle detection and also recognize photon spin angular momentum.