Optical properties of surface micromachining with randomly distributed etch holes

Optical micromachining or microelectromechanical systems (MEMS) typically require etch holes to reduce the time required to release the micromechanical structure during the sacrificial undercutting. However, high-order diffraction beams generated by the periodic etch-hole array often deteriorate the optical performance by generating noise and erroneous crosstalk signals in most optical systems. In this study, we examined the diffraction from a perforated micromirror and proposed a random distributed etch-hole layout. Due to the superposition of cosine functions with random periods, noise caused by high-order beams can be averaged effectively.