Fig. 1. Schematic of full-field heterodyne interferometer

Fig. 2. Physical map of dual-frequency laser source

Fig. 3. Interference data measured at close range with interference cavity length of 0.25 m. (a) Interference data cube at different time; (b) interference data curves of fixed point at different time

Fig. 4. Surface measurement result at close distance

Fig. 5. RMS after repeated measurement for 48 times

Fig. 6. Measurement result of system error

Fig. 7. Collected interference data with interference cavity length of 25 m. (a) Interference data cube at different time; (b) interference data curve of fixed point at different time

Fig. 8. Measured surface with interference cavity length of 25 m. (a) Error of measured surface; (b) 3D map of measured surface