Abstract Orbital Angular Momentum (OAM) is a typical spatial mode of an Electro-Magnetic (EM) wave. Correctly detecting the OAM mode is fundamental and of foremost importance when applying the phenomenon to wireless transmission in free space. It is found that when rotating an OAM wave. a rotational Doppler shift that is proportional to the rotation speed and the OAM mode number can b... https://parisnaturalfoodes.shop/product-category/earthpaste-lemon-twist/