Free-space remote detection of a spinning object using the combined vortex beam

Area of Science:

• Optics and Photonics
• Remote Sensing
• Wave Phenomena

Background:

• The rotational Doppler effect (RDE) utilizing orbital angular momentum (OAM) is key for remote sensing of rotating objects.
• A major limitation in long-range detection is the weak echo signal power.

Purpose of the Study:

• To propose and demonstrate a novel detection scheme using combined vortex beams (CVB) to enhance echo signal power for RDE-based remote sensing.
• To establish a remote sensing model for rotational speed based on RDE and investigate probe beam parameters.

Main Methods:

• Generation of a combined vortex beam (CVB) via coherent beam combining (CBC) technology as the probe beam.
• Development of a rotational speed remote sensing model based on RDE.
• Experimental validation of the CVB scheme with a rotating rough surface.

Main Results:

• The CVB detection scheme significantly enhances echo signal intensity and detection distance compared to superposition vortex beams (SVB).
• Detailed analysis of the measuring range and accuracy of rotational speed.
• First experimental demonstration of RDE from CVB interaction with a rotating rough surface.

Conclusions:

• The proposed CVB-based RDE detection scheme offers a substantial improvement for remote sensing of spinning objects.
• This method provides a valuable reference for practical applications in long-range rotational speed detection.