Novel zero-expansion materials for precision optical substrates

Yogesh Mehrotra, Dinesh Kumar Agrawal, V. S. Stubican

Research output: Contribution to journalArticle

Abstract

A novel family of "germania-modified cordierite" ceramics has been developed for fabrication of precision optical components. Compositions in this family possess zero average coefficient of thermal expansion (CTE) over selected temperature regions. Moreover, the zero CTE can be "tailored" to a desired temperature range of operation by varying the relative proportions of Ge02 and Si02 in the modified cordierite structure. Thermal diffusivity of these ceramics is more than twice that of ULETM glass, a current state-of-the-art material for precision mirror substrates. In addition, germanium-cordierites possess high specific stiffness and low thermal moment/rigidity ratio. Controllable fine-grained structure enables good polishability and offers the potential for an optical quality surface. These thermal and mechanical properties make Ge-cordierite an excellent material for optical and structural applications. The theoretical basis for germania substitution for silica in the pure cordierite struc-ture has been examined. Material characteristics including solid solubility and sinterability have been considered. All the germanium-cordierite compositions presented in this study are morphologically single phase and microstructurally homogeneous materials. These properties along with "tailorable" zero CTE characteristics offer the potential of employing cordierites for high precision optics.

Original languageEnglish (US)
Pages (from-to)192-201
Number of pages10
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume505
DOIs
StatePublished - Dec 26 1984

Fingerprint

cordierite
Germanium
Coefficient of Thermal Expansion
Substrate
Thermal expansion
expansion
Zero
Substrates
germanium
thermal expansion
Thermal Diffusivity
Surface Quality
Thermal diffusivity
Thermal Properties
Solubility
Fine Structure
Chemical analysis
Silica
Rigidity
Mechanical Properties

All Science Journal Classification (ASJC) codes

  • Applied Mathematics
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Computer Science Applications

Cite this

Mehrotra, Yogesh ; Agrawal, Dinesh Kumar ; Stubican, V. S. / Novel zero-expansion materials for precision optical substrates. In: Proceedings of SPIE - The International Society for Optical Engineering. 1984 ; Vol. 505. pp. 192-201.
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Novel zero-expansion materials for precision optical substrates. / Mehrotra, Yogesh; Agrawal, Dinesh Kumar; Stubican, V. S.

In: Proceedings of SPIE - The International Society for Optical Engineering, Vol. 505, 26.12.1984, p. 192-201.

Research output: Contribution to journalArticle

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