Robust detection of a rotational Doppler shift with randomly fluctuated light

Abstract

The complex external environment, such as obstruction and turbulence, poses significant limitations on the applications of rotational Doppler detection. The active manipulation of randomly fluctuated light has been proven effective in mitigating external environmental perturbations. Here, as an example, a partially coherent source with petal-like focal (or far) field distribution is constructed specifically for detecting rotational Doppler frequency shifts. The experiment involved conducting rotational Doppler detection under obstruction or turbulence conditions, and the results are compared with the fully coherent counterpart. The results demonstrate that the use of a partially coherent source can address the frequency-shift broadening problem due to the obstruction-induced beam information loss and mitigate it due to the turbulence-induced beam misalignment. These advantages make the proposed approach applicable to velocity metrology in complex environments.