Fabrication of CVD diamond optics with antireflective surface structures

Citation
Vg. Ralchenko et al., Fabrication of CVD diamond optics with antireflective surface structures, PHYS ST S-A, 174(1), 1999, pp. 171-176
Citations number
10
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICA STATUS SOLIDI A-APPLIED RESEARCH
ISSN journal
00318965 → ACNP
Volume
174
Issue
1
Year of publication
1999
Pages
171 - 176
Database
ISI
SICI code
0031-8965(199907)174:1<171:FOCDOW>2.0.ZU;2-8
Abstract
Polycrystalline CVD diamond is an excellent material for advanced optical a pplications, especially in the IR spectral range. However, one drawback of diamond is the significant reflection loss of 29%, caused by its high refra ction index n = 2.4. We fabricated subwavelength, "moth-eye" antireflective structured (ARS) surfaces (two-dimensional array of pyramids) by filling, with CVD diamond the inverted pyramids etched in a Si substrate, followed b y the substrate removal to obtain the patterned diamond replica. An increas e in IR transmission up to T = 80% was observed at wavelengths lambda > 10 mu m for the ARS surfaces compared to T = 71% for flat surfaces even at the non-optimized geometry of the surface relief. A further increase in transm ission could be achieved by combining ARS and a single layer AR coating of amorphous carbon.