Déformation photoinduite dans les films minces contenant des ...

PP 2VChapter 4. Photomechanical response of hybrid metal/azo-polymer layered structures129a fara line2020A (nm)100-1000 AA linefar100-10a line-20-200 1 2 3 4 5 6 70 1 2 3 4 5 6 7!m!m(a)(b)a tip = a line – a fara far20pastel-00527388, version 1 - 19 Oct 2010A (nm)100-10-200 1 2 3 4 5 6 7!m(c)Figure 4.11: Photomechanical effects of the tip-sample interactions (2 V ) in a solgelSi-DR1 film: far-field and near-field photodeformation. ā line = 4.5 nm, A 0 line =18.4 nm, A 0 far= 20 nm.4.2.1.3 DiscussionWe have observed a tip-related near-field photodeformation effect, which can be comparableto the photodeformation induced under far-field illumination. In Figure 4.12 wesummarize the near-field deformation amplitudes observed under p-polarized uniformillumination (a) and the average near-field deformation ā tip observed under projectionof a p-polarized interference pattern (b), for different doses and tip-sample interactionamplitudes. As expected, increasing the dose increases the deformation height, whichtends to saturate for high doses (a, ✕). However, the near-field effect seems to criticallydepend on the tip-surface interaction. In particular, the photodeformation stronglyvaries when changing the tip-to-sample distance by only a few nanometers, which is atoo steep behavior to be attributed to a near-field optical effect only.The irradiation using an interference pattern has shown that the near-field photodeformationis present in both the bright and the dark fringes, while we would have expected