This chapter provides the main background for the electromagnetic theory used in this book. 本章闡述本書(shū)所用的電磁場(chǎng)理論的主要基礎。
Based on the classical theory of electromagnetism, the relation and the difference between OAM and the parameter of the beam in paraxial approximation are analyzed. 從經(jīng)典電磁場(chǎng)理論出發(fā)，主要介紹了傍軸近似條件下，光束的軌道角動(dòng)量和光束的參數之間的關(guān)系。
