Three-Dimensional Second-Harmonic Generation Microscopy of Semiconductor Nanowires using Tailored Focal Fields
Kallioniemi, Leevi (2019)
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Julkaisun pysyvä osoite on
Nonlinear optical (NLO) microscopy has raised much interest with its superior capabilities in high-resolution imaging of a variety of nanostructures without photodamage or labeling. Contrast in NLO microscopy relies on NLO eﬀects, which are sensitive to the crystal structure and the physical properties of the sample at nanoscale. It turns out that the polarization of the input electromagnetic ﬁeld also matters in the improvement of image contrast. In the context of NLO microscopy, it is evident that the capability to control the polarization in three dimensions at the beam focus is important. Such capability is important in the characterization and exploitation of individual nanostructures with well-known or even unexplored NLO properties. The goal of this Thesis was to perform SHG microscopy of individual vertically-aligned GaAs nanowires in three dimensions. Previously, such kind of nanowires was found to be very sensitive to the electric ﬁeld component along the beam propagation axis, which can be taken advantage of when mapping the longitudinal electric ﬁeld distribution of the beam. We also present a method to redistribute the longitudinal electric ﬁeld of a tightly focused ﬁrst-order Hermite-Gaussian (HG10) beam by spatially phase-shaping the beam. By using the presented techniques, the longitudinal electric ﬁeld distribution of a spatially phase-shaped HG10 beam was veriﬁed for the ﬁrst time in three dimensions.
- Kandidaatintutkielmat