title: Impact of Water Adsorption on Nonlinear Optical Properties of Functionalized Porous Silicon.
abstract: The porous silicon (PS) surface modification diagnostics due to functionalization and water adsorption/desorption processes were provided by the self-action effects of picosecond range pulsed laser radiation at 1064 nm. It was shown that the PS surface functionalization-oxide removal, alkylation, and oxidation-resulted in a refractive nonlinear optical (NLO) response sign turn to self-focusing (Δn>0) versus the self-defocusing (Δn<0) observed in the aged PS. The sensitivity of the proposed technique was revealed to water adsorption/desorption from the chemically oxidized PS interface. For the dried PS, the self-defocusing effect with corresponding NLO cubic susceptibility Re(χ(3))∼-4.7·10-9esu was observed versus the self-focusing one (∼5·10-8esu) for the PS positioned in saturated water vapor at room temperature. The obtained results demonstrate high sensitivity and wide versatility of the proposed readout technique based on pulsed laser radiation self-action at 1064 nm to the PS surface modification monitoring/diagnostics applications.
authors.affiliation: Institute of Physics NAS of Ukraine, Prospect Nauky 46, Kyiv, 03028, Ukraine. andrey.uklein@gmail.com.
authors.forename: Andrii V
authors.initials: AV
authors.lastname: Uklein
authors.affiliation: Institute of Physics NAS of Ukraine, Prospect Nauky 46, Kyiv, 03028, Ukraine.
authors.forename: Volodymyr V
authors.initials: VV
authors.lastname: Multian
authors.affiliation: Taras Shevchenko National University of Kyiv, 64 Volodymyrska Str., Kyiv, 01601, Ukraine.
authors.forename: Bogdan V
authors.initials: BV
authors.lastname: Oliinyk
authors.affiliation: Taras Shevchenko National University of Kyiv, 64 Volodymyrska Str., Kyiv, 01601, Ukraine.
authors.forename: Volodymyr V
authors.initials: VV
authors.lastname: Doroshchuk
authors.affiliation: Taras Shevchenko National University of Kyiv, 64 Volodymyrska Str., Kyiv, 01601, Ukraine.
authors.forename: Sergei A
authors.initials: SA
authors.lastname: Alekseev
authors.affiliation: Lyon Institute of Nanotechnologies, INL, CNRS UMR-5270, INSA de Lyon, 7 avenue Jean Capelle, Bat. Blaise Pascal, Lyon, 69621 Villeurbanne cedex, France.
authors.forename: Volodymyr V
authors.initials: VV
authors.lastname: Lysenko
authors.affiliation: Institute of Physics NAS of Ukraine, Prospect Nauky 46, Kyiv, 03028, Ukraine.
authors.forename: Mykhailo S
authors.initials: MS
authors.lastname: Brodyn
authors.affiliation: Institute of Physics NAS of Ukraine, Prospect Nauky 46, Kyiv, 03028, Ukraine.
authors.forename: Volodymyr Ya
authors.initials: VY
authors.lastname: Gayvoronsky
keywords: Nonlinear optical response; Porous silicon functionalization; Surface diagnostics; Water adsorption/desorption