Optical absorption of ion-beam sputtered amorphous silicon coatings

J. Steinlechner, I.W. Martin*, R. Bassiri, A. Bell, M.M. Fejer, J. Hough, A. Markosyan, R.K. Route, S. Rowan, Z. Tornasi

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

18 Citations (Web of Science)

Abstract

Low mechanical loss at low temperatures and a high index of refraction should make silicon optimally suited for thermal noise reduction in highly reflective mirror coatings for gravitational wave detectors. However, due to high optical absorption, amorphous silicon (aSi) is unsuitable for being used as a direct high-index coating material to replace tantala. A possible solution is a multimaterial design, which enables exploitation of the excellent mechanical properties of aSi in the lower coating layers. The possible number of aSi layers increases with absorption reduction. In this work, the optimum heat treatment temperature of aSi deposited via ion-beam sputtering was investigated and found to be 450 degrees C. For this temperature, the absorption after deposition of a single layer of aSi at 1064 nm and 1550 nm was reduced by more than 80%.
Original languageEnglish
Article number062005
Number of pages9
JournalPhysical Review D
Volume93
Issue number6
DOIs
Publication statusPublished - 25 Mar 2016
Externally publishedYes

Keywords

  • INTERNAL-FRICTION
  • CRYSTALLINE

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