Document Type

Article

Publication Date

2019

Department/Program/Center

Physics and Astronomy

Abstract

Applications of wavelet analysis in ultra-thin film transient reflectivity (TR) measurements have been investigated. Advantages of utilizing different localized wavelet bases, in position and time, have been addressed on the residual TR signals. Morse wavelets have been used to obtain information from the abrupt oscillatory modes in the signal, which are not distinguishable with conventional methods such as Fourier transforms. These abrupt oscillatory modes are caused by the surface, interface, or any short-lived oscillatory modes which are suppressed in the TR signal in ultra-thin films. It is demonstrated that by choosing different Morse wavelets, information regarding different oscillatory modes in the TR signal of a heterostructure thin film is achievable. Moreover, by performing wavelet analysis on multiferroic heterostructures, oscillatory modes with very close energy ranges are easily distinguishable. For illustration, residuals of the TR signals have been obtained by a pumpprobe setup in reflectivity mode on La0.7Sr0.3MnO3/SrTiO3 and BaTiO3/La0.7Sr0.3MnO3/SrTiO3 samples, where sufficient signal to noise ratios have been achieved by taking multiple scans. The residual signals have been analyzed with Morse wavelets, and multiple oscillatory modes with close energy ranges have been observed and distinguished. This approach can isolate the location of various oscillatory modes at the surface, interface and in the bulk of the heterostructure sample.

Source Citation

Sarraf, S. Y., Trappen, R., Kumari, S., Bhandari, G., Mottaghi, N., Huang, C. Y., Cabrera, G. B., Bristow, A. D., & Holcomb, M. B. (2019). Application of wavelet analysis on transient reflectivity in ultra-thin films. Optics Express, 27(10), 14684. https://doi.org/10.1364/oe.27.014684

Comments

© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

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