A Full Closed-Loop Rotary Laser Scanning Angle Measurement System Based on an Optical Frequency Comb

Accurately measuring spatial angles in large-scale metrological scenarios holds critical significance for applications in geodesy and industrial large-scale metrology, which long-term face challenges due to the increase of nonlinearity and the massive unknown disturbances coupled into the large-scale dimensions. Directly building a physical mapping from an optical frequency comb (OFC) to spatial angels can overcome the above fundamental issues but has never been achieved. Here, we propose a full closed-loop laser scanning angle measurement system by introducing a rotary OFC technology. In the system, the rotary laser pulses segment the spatial angles based on the repetition frequency locked on the atomic clock, which guarantee the traceability between the atomic clock and spatial angles. Moreover, the consecutive pulses’ intervals received by the detector can be seemed as a feedback signal to adjust the rotary speed of the turntable. Two validation experiments demonstrate that the proposed technology effectively compensates for disturbances caused by temperature variations and the resultant angle can maintain a high precision by counting the pulse numbers of an OFC. This technology offers enhanced precision and traceability, thereby advancing large-scale metrology for applications in geodesy and industrial settings.