Heidelberg 2015 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
Q: Fachverband Quantenoptik und Photonik
Q 61: Ultrashort Laser Pulses II
Q 61.2: Vortrag
Donnerstag, 26. März 2015, 14:45–15:00, K/HS2
High-sensitivity measurement of the nonlinear refractive index of noble gases — •Andreas Blumenstein1, Milutin Kovacev2, Uwe Morgner2,3, Peter Simon1, and Tamas Nagy1,2 — 1Laser-Laboratorium Göttingen e.V., Hans-Adolf-Krebs-Weg 1, Göttingen — 2Leibniz Universität Hannover, Institut für Quantenoptik, Welfengarten 1, Hannover — 3Laser Zentrum Hannover e.V., Hollerithallee 8, Hannover
The optical Kerr-effect which induces an intensity-dependent change in the refractive index n = n0 + n2I can lead to numerous spectacular effects (e.g. spectral broadening). However, the measurement of n2 especially in gases is very difficult due to its low value. In most experiments the actually measured quantity is the accumulated nonlinear phase: Δ Φ (x,y) = 2π /λ 0∫0L n2I(x,y,z)dz. In a usual geometry where a laser beam is focused into the nonlinear medium there are two basic problems: (i) the interaction length is severely limited to the order of the Rayleigh-length and (ii) it is difficult to precisely determine the 3D intensity distribution of the beam. The former problem limits the sensitivity, the latter the absolute precision of the measurement. In contrast to previous arrangements we use a hollow waveguide to host the nonlinear interaction allowing well-defined intensity distribution throughout a substantially larger interaction length. Our technique provides dramatically higher sensitivity and precision in the determination of nonlinear refraction in gases than former approaches.