%0 Journal Article %1 goetz2016investigation %A Goetz, Sebastian %A Razinskas, Gary %A Krauss, Enno %A Dreher, Christian %A Wurdack, Matthias %A Geisler, Peter %A Pawłowska, Monika %A Hecht, Bert %A Brixner, Tobias %D 2016 %J Appl. Phys. B %K experiment gold nano-optics plasmon %N 4 %P 94 %R 10.1007/s00340-016-6370-7 %T Investigation of the nonlinear refractive index of single-crystalline thin gold films and plasmonic nanostructures %V 122 %X The nonlinear refractive index of plasmonic materials may be used to obtain nonlinear functionality, e.g., power-dependent switching. Here, we investigate the nonlinear refractive index of single-crystalline gold in thin layers and nanostructures on dielectric substrates. In a first step, we implement a z-scan setup to investigate ~100-µm-sized thin-film samples. We determine the nonlinear refractive index of fused silica, n2(SiO2) = 2.9 × 10^(−20) m^2/W, in agreement with literature values. Subsequent z-scan measurements of single-crystalline gold films reveal a damage threshold of 0.22 TW/cm^2 and approximate upper limits of the real and imaginary parts of the nonlinear refractive index, |n2′(Au)| < 1.2 × 10^(−16) m^2/W and |n2″(Au)| < 0.6 × 10^(−16) m^2/W, respectively. To further determine possible effects of a nonlinear refractive index in plasmonic circuitry, interferometry is proposed as a phase-sensitive probe. In corresponding nanostructures, relative phase changes between two propagating near-field modes are converted to amplitude changes by mode interference. Power-dependent experiments using sub-10-fs near-infrared pulses and diffraction-limited resolution (NA = 1.4) reveal linear behavior up to the damage threshold (0.23 times relative to that of a solid single-crystalline gold film). An upper limit for the nonlinear power-dependent phase change between two propagating near-field modes is determined to Δφ < 0.07 rad.

@article{goetz2016investigation, abstract = {The nonlinear refractive index of plasmonic materials may be used to obtain nonlinear functionality, e.g., power-dependent switching. Here, we investigate the nonlinear refractive index of single-crystalline gold in thin layers and nanostructures on dielectric substrates. In a first step, we implement a z-scan setup to investigate ~100-µm-sized thin-film samples. We determine the nonlinear refractive index of fused silica, n2(SiO2) = 2.9 × 10^(−20) m^2/W, in agreement with literature values. Subsequent z-scan measurements of single-crystalline gold films reveal a damage threshold of 0.22 TW/cm^2 and approximate upper limits of the real and imaginary parts of the nonlinear refractive index, |n2′(Au)| < 1.2 × 10^(−16) m^2/W and |n2″(Au)| < 0.6 × 10^(−16) m^2/W, respectively. To further determine possible effects of a nonlinear refractive index in plasmonic circuitry, interferometry is proposed as a phase-sensitive probe. In corresponding nanostructures, relative phase changes between two propagating near-field modes are converted to amplitude changes by mode interference. Power-dependent experiments using sub-10-fs near-infrared pulses and diffraction-limited resolution (NA = 1.4) reveal linear behavior up to the damage threshold (0.23 times relative to that of a solid single-crystalline gold film). An upper limit for the nonlinear power-dependent phase change between two propagating near-field modes is determined to Δφ < 0.07 rad.}, added-at = {2020-02-24T10:39:06.000+0100}, author = {Goetz, Sebastian and Razinskas, Gary and Krauss, Enno and Dreher, Christian and Wurdack, Matthias and Geisler, Peter and Pawłowska, Monika and Hecht, Bert and Brixner, Tobias}, biburl = {https://www.bibsonomy.org/bibtex/22c501fcc92d9af6f004812d8089e90c8/ep5optics}, day = 12, doi = {10.1007/s00340-016-6370-7}, file = {Goetz et al. - 2016 - Investigation of the nonlinear refractive index of.pdf:C\:\\Users\\scherzad\\Zotero\\storage\\CXWBCTTS\\Goetz et al. - 2016 - Investigation of the nonlinear refractive index of.pdf:application/pdf}, interhash = {e7394149d0a807e57549f6cb1d6b7a94}, intrahash = {2c501fcc92d9af6f004812d8089e90c8}, issn = {1432-0649}, journal = {Appl. Phys. B}, keywords = {experiment gold nano-optics plasmon}, language = {en}, month = {04}, number = 4, pages = 94, timestamp = {2020-02-24T10:39:06.000+0100}, title = {Investigation of the nonlinear refractive index of single-crystalline thin gold films and plasmonic nanostructures}, urldate = {2020-02-24}, volume = 122, year = 2016 }