Influence of Deposition Method on Refractive Index of SiO2 and TiO2 Thin Films for Anti-reflective Multilayers |
Myung-Keun Song, Woo-Seok Yang1, Soon-Woo Kwon2, Yo-Seung Song, Nam-Ihn Cho3, Deuk-Yong Lee4 |
Department of Materials Engineering, Korea Aerospace University 1Nano Bio-photonics Team, Korea Electronics Technology Institute 2Department of Advanced Materials Engineering, Sungkyunkwan University 3Department of Electronic Engineering, Sun Moon University 4Department of Materials Engineering, Daelim College of Technology |
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ABSTRACT |
Anti-Reflective (AR) thin film coatings of $SiO_2$ (n= 1.48) and $TiO_2$ (n=2.17) were deposited by ion-beam assisted deposition (IBAD) with End-Hall ion source and conventional electron beam (e-beam) evaporation to investigate the effect of deposition method on the refractive indicies (n) of the fIlms. Green-light generation using a GaAs laser diode was achieved via excitation of the second harmonic. The latter resulted from the transmission of the fundamental guided-mode wave of 1064 nm through periodically poled $LiNbO_3$. Large differences in the refractive indicies of each of the layers in the multilayer coating may improve AR performance. IBAD of $SiO_2$ reduced its refractive index from 1.45 to 1.34 at 1064 nm. Conversely, e-beam evaporation of $TiO_2$ increased its refractive index from 1.80 to 2.11. In addition, no fluctuations in absorption at the wavelength of 1064 nm were found. The results suggest that films prepared by different deposition methods can increase the effectiveness of multilayer AR coatings. |
Key words:
$SiO_2$$TiO_2$, Anti-reflective (AR) coatings, Refractive index (n), electron-beam evaporation, IBAD (Ion Beam Assisted Deposition) |
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