Vectorial Doppler complex spectrum and its application to the rotational detection

Based on vectorial polarized fields of light applied to detect the rotational velocity by the rotational Doppler effect, we propose a method to measure the magnitude and direction of the rotational velocity simultaneously for a general rotating surface. When the rotational surface is rough, the scattered vectorial Doppler signal spectrum is complex. In this paper, we make complex spectrum analyses using the orbital angular momentum modal expansion method and measure the rotational velocity in the experiment.