Visible and IR light waveguiding in ferroelectric Na0.5K0.5NbO3 thin films
2005 (English)In: Integrated Ferroelectrics, ISSN 1058-4587, Vol. 69, 277-286 p.Article in journal (Refereed) Published
High-quality ferroelectric thin films are attractive materials for integrated optics applications including electro-optic waveguide modulators and frequency doubling secondharmonic generators. Several fefroelectric thin film materials, such as BaTiO3, KNbO3, LiNbO3, and (Pb,La)(ZrTi)O-3, have been investigated regarding their optical and waveguiding properties. Recently the first results on waveguiding in ferroelectric Na0.5K0.5NbO3 (NKN) thin films were presented. Perovskite NKN films have previously been investigated as electrically tunable material for low loss rf and microwave applications. Na0.5K0.5NbO3 thin films of thickness 0.5-1.0 mum have been deposited on Nd:YAlO3(001) and Al2O3(0112) substrates using rf-magnetron sputtering of a stoichiometric, high-density ceramic target. X-ray diffraction measurements confirmed films grown highly (00l) oriented on the perovskite Nd:YAlO3 substrate and preferentially c-axis oriented on the single crystal r-cut sapphire substrate. Optical and waveguiding properties were characterized using a Metricon 2010 prism-coupling apparatus with a rutile prism. Dark-line spectra were obtained at visible light (lambda = 632.8 nm) as well as at infrared optical communication wavelengths, lambda = 1319 nm and lambda = 1549 nm, in both transverse electric (TE) and transverse magnetic (TM) polarizations. Sharp dips corresponding to waveguide propagation modes in the thin film layers where observed for both substrates. The calculated refractive index values and corresponding birefringence (Deltan = n(TM) - n(TE) = n(e) - n(o)) as a function of wavelength has been compared. Generally a larger birefringence is observed for the NKN film on Nd:YAlO3, which is in agreement with the larger degree of preferential c-axis orientation measured by XRD.
Place, publisher, year, edition, pages
2005. Vol. 69, 277-286 p.
Na0.5K0.5NbO3 films, rf-magnetron sputtering, waveguiding, refractive index, birefringence, prism coupling, sapphire
Other Materials Engineering
IdentifiersURN: urn:nbn:se:kth:diva-14526DOI: 10.1080/10584580590899027ISI: 000226933000031ScopusID: 2-s2.0-33644782690OAI: oai:DiVA.org:kth-14526DiVA: diva2:332567
QC 20100525 QC 20111011.2010-08-052010-08-052011-10-11Bibliographically approved