Optical properties of surface micromachined mirrors with etch holes

Jun Zou, Michal Balberg, Colin Byrne, Chang Liu, David J. Brady

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

We have investigated the optical properties of surface-micromachined polycrystalline silicon reflectors within the visible spectral range at five different wavelengths. The measurement results of the reflectivity of various microreflectors at four different incident angles (20°, 30°, 45°, and 60°) are presented. Optical properties of microreflectors realized using the multiuser MEMS process (MUMPS) have been investigated. Our studies have found that etch holes, widely used in the surface micromachining process to reduce the time for releasing structures by sacrificial undercutting, have a great influence on the optical properties of micromachined mirrors. Diffraction patterns created by two-dimensional etch-hole arrays on micromachined mirrors have been investigated. The diffraction by etch holes obeys the Fraunhofer diffraction theory when a collimated light source (e.g., a laser beam) is incident. We have shown that when the dimension of etch holes increases, an increasing portion of the incident power will be diffracted and transmitted due to etch holes, leading to decreasing reflectivity of surface micromachined mirrors.

Original languageEnglish (US)
Pages (from-to)506-513
Number of pages8
JournalJournal of Microelectromechanical Systems
Volume8
Issue number4
DOIs
StatePublished - Dec 1999

ASJC Scopus subject areas

  • Mechanical Engineering
  • Electrical and Electronic Engineering

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