Regensburg 2013 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 2: Ultrafast phenomena
HL 2.4: Vortrag
Montag, 11. März 2013, 10:15–10:30, H2
Longitudinal fields in focused terahertz beams — •Stephan Winnerl1, Ralf Hubrich1, Martin Mittendorff1,2, Harald Schneider1, and Manfred Helm1,2 — 1Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — 2Technische Universität Dresden, Dresden, Germany
In textbooks electromagnetic waves are often described as infinitely extended plane waves, which are of purely transverse character. For beams of finite size, however, also longitudinal fields are expected. In case of focused radially polarized beams, the longitudinal fields can actually be stronger as compared to the transverse components. This has been found in experiments recording the intensity of near-infrared beams. In our study we directly record the electric field of single cycle terahertz pulses of radial and linear polarization. This enables us to reveal the phase relation between longitudinal and transverse fields. The obtained value of π/2 is of universal nature as it does not depend on the type of mode, frequency or focusing condition. Additionally we demonstrate that the longitudinal components of radially polarized beams exhibit superior focusing properties.