Fig. 1. Characteristics of low coherent micro-interference signal with high aspect ratio structure

Fig. 2. Simulation process

Fig. 3. Distribution of detecting light field at focal plane

Fig. 4. Simulation of imaging process

Fig. 5. Schematic of equivalent principle

Fig. 6. Simulation of vertical scanning process

Fig. 7. Schematic of attenuation factor and point spread function

Fig. 8. Location of tested sampling point of Si-based trench micro-structure with aspect ratio of 5∶1

Fig. 9. Simulated interference signals of Si-based trench micro-structure with aspect ratio of 5∶1 under different polarization directions

Fig. 10. Experimental results of Si-based MEMS trench micro-structure with aspect ratio of 5∶1（the interference signals are the result of CEEMDAN preprocessing）

Fig. 11. Simulated interference signals after splicing

Fig. 12. Experimental results of Si-based MEMS trench micro-structure with aspect ratio of 80∶3

Fig. 13. Experimental interference signal after splicing

Fig. 14. Comparison diagram of normalized experimental interference signal and simulated interference signal

Fig. 15. Envelope comparison of experimental interference signal and simulated interference signal

Fig. 16. Frequency distribution comparison of experimental interference signal and simulated interference signal