Bulk-micromachined tunable Fabry–Perot microinterferometer for the visible spectral range

Abstract

Ž. The design, fabrication and measured characteristics of a bulk-micromachined tunable Fabry-Perot microinterferometer FPMI for the visible spectral range are presented. The FPMI is formed by two parallel 40 nm thick silver mirrors supported by a 300 nm low tensile Ž . stress silicon nitride membrane with a square aperture side length of 2 mm and initial cavity gap of 1.2 mm. One of the mirrors is fixed, the other is under tension on a movable Si frame, which is electrostatically deflected, using several distributed electrodes, to control Ž . cavity spacing and mirror parallelism. Performance achieved is: high flatness of the mirrors lr10 for the visible part of the spectrum , Ž . low control voltages -21 V for 450 nm deflection and simple fabrication. q 1999 Elsevier Science S.A. All rights reserved.

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