Rotational Doppler effect on reflection upon an ideal rotating propeller

Abstract

The rotational Doppler shift is the counterpart of the usual linear Doppler effect for rotating bodies. We study by an experimental approach coupled with theoretical considerations the rotational shift of a fundamental laser light reflected on an ideal rotating propeller. We decompose the reflected light on a Laguerre–Gaussian basis and show that only modes having the same rotational symmetry as the propeller are involved in the decomposition. The latter experience a frequency shift proportional to the rotation frequency of the propeller and the topological charge of the beam. Extensions of this work in the microwave domain are then considered.

Rotational Doppler Effect: A Review

“…[64][65][66] It is only a matter of decomposition in the LG basis behind the occulting object. Besides, instead of being used in a bistatic configuration that investigates the transmitted light, the same principle can be used in a monostatic configuration in reflection, [67] leading to the same kind of conclusion: rotational Doppler effects have been evidenced. Experiments have also been performed on light that changed its spin due to birefringence from a rotating gas, but using the rotational Doppler effect with circularly polarized light (SAM).…”