Fig. 1. Configuration and physical principles of the system. (a) The system schematic. (b) The normalized defocusing curve with a certain objective. (c) The calibrated linear range.

Fig. 2. Nd:  YVO4 laser output power before and after temperature control. (a) Laser output power before temperature control. (b) Laser output power after temperature control.

Fig. 3. Normalized linear ranges with different objective lenses. (a) Linear range with the objective of NA=0.65. (b) Linear range with the objective of NA=0.55. (c) Linear range with the objective of NA=0.3.

Fig. 4. Measured results of the silicon grating profile. (a) Grating profile measured by AFM. (b) Grating profile measured by our system.

Fig. 5. Physical maps of the micro-gyroscope and the rotor. (a) The micro-gyroscope to be measured. (b) Upper: the rotor corroded from the micro-gyroscope; lower: the top view of the rotor.

Fig. 6. Cross section of the rotor along the scanning direction in Fig. 5(b). The red circle shows the edge to be measured.

Fig. 7. Measurement results. Left: Lateral scanning diagram of the rotor; right: the edge slope of the rotor.