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Applied Optics

Applied Optics


  • Vol. 41, Iss. 16 — Jun. 1, 2002
  • pp: 3285–3293

Thermally invariant dielectric coatings for micromirrors

Wei Liu and Joseph J. Talghader  »View Author Affiliations

Applied Optics, Vol. 41, Issue 16, pp. 3285-3293 (2002)

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Thermal expansion-induced curvature becomes a major effect in micromirrors as the mirror diameter exceeds 100 µm. Such mirrors are used for optical switching, scanning, and many other applications. By using multilayer coatings instead of a single metal reflector, one can use the mechanical properties of the multilayer to create mirrors with zero curvature across temperature. We demonstrate the fabrication of such thermally invariant mirrors using dielectric coatings. A semianalytic model based on free-plate elastic theory is developed that uses empirical parameters in place of the true thermal expansion coefficients of the coating materials. Micromirrors are demonstrated that maintain their design curvature to within λ/60 for λ = 633 nm across an operating range from 21 °C to 58 °C.

© 2002 Optical Society of America

OCIS Codes
(120.6810) Instrumentation, measurement, and metrology : Thermal effects
(220.4830) Optical design and fabrication : Systems design
(230.3990) Optical devices : Micro-optical devices
(230.4040) Optical devices : Mirrors
(310.1620) Thin films : Interference coatings

Original Manuscript: October 15, 2001
Revised Manuscript: January 10, 2002
Published: June 1, 2002

Wei Liu and Joseph J. Talghader, "Thermally invariant dielectric coatings for micromirrors," Appl. Opt. 41, 3285-3293 (2002)

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