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Proceedings Paper

Optical and dielectric properties of CVD polycrystalline diamond plates
Author(s): Ricardo S. Sussmann; Christopher J. H. Wort; Charles G. Sweeney; J. L. Collins; C. N. Dodge; James Anthony Savage
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Paper Abstract

Optical, and dielectric properties of free-standing plates of polycrystalline diamond grown by chemical vapor deposition (CVD) are reported and compared with Type IIa natural single crystal diamond specimens. Ultra-violet, visible, and Fourier transform infrared spectroscopies have been used to assess the optical quality of the material. It has been found that over most of the spectral range, except at short wavelengths close to the fundamental edge, the transmission of the CVD plates is almost indistinguishable from that of Type IIa natural diamond. In the visible and ultra-violet the transmission is reduced due to a combination of scattering and true absorption. The imaging potential of CVD diamond at 10.6 micrometers wavelength has been assessed by measurements of modulation transfer function (MTF). The intrinsic optical quality of the material is adequate for imaging in the infrared region but improvements are needed to planarize the optical surfaces in order to minimize astigmatism and lensing. Measurements of dielectric constant and dielectric loss tangent were performed at 36 GHz, 72 GHz, and 144 GHz microwave frequencies using an open resonator technique. Bulk values of dielectric loss tangent as low as 73 X 10-6 have been observed. There is evidence that these values may still be affected by surface effects and that the true value for the bulk dielectric loss tangent in high quality CVD diamond plates studied in this paper could be as low as 30 X 10-6 or lower over a wide temperature range up to 250 degree(s)C, the lowest value of loss tangent so far reported for CVD diamond.

Paper Details

Date Published: 28 September 1994
PDF: 10 pages
Proc. SPIE 2286, Window and Dome Technologies and Materials IV, (28 September 1994); doi: 10.1117/12.187344
Show Author Affiliations
Ricardo S. Sussmann, DIAMANX Ltd. (United Kingdom)
Christopher J. H. Wort, DIAMANX Ltd. (United Kingdom)
Charles G. Sweeney, DIAMANX Ltd. (United Kingdom)
J. L. Collins, DIAMANX Ltd. (United Kingdom)
C. N. Dodge, DIAMANX Ltd. (United Kingdom)
James Anthony Savage, Defence Research Agency Malvern (United Kingdom)

Published in SPIE Proceedings Vol. 2286:
Window and Dome Technologies and Materials IV
Paul Klocek, Editor(s)

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