Hannover 2010 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 48: Ultrashort Laser Pulses: Miscellaneous
Q 48.3: Vortrag
Donnerstag, 11. März 2010, 11:00–11:15, F 342
Intra-cavity interferometric autocorrelation for ultraviolet pulses by spontaneous parametric down-conversion — •Patrick Michelberger1,2,3, Roland Krischek1,2, Witlef Wieczorek1,2, Akira Ozawa1, and Harald Weinfurter1,2 — 1Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany — 2Department für Physik, Ludwig-Maximilians-Universität, 80797 München, Germany — 3Clarendon Laboratory, Oxford University, Parks Road, Oxford, OX1 3PU, UK
Autocorrelation is a common method to estimate the duration of ultra-short laser pulses. In the ultra-violet regime, employing the customary process of second harmonic generation is challenging due to absorption in nonlinear crystals at short wavelengths. Here we show how to utilise spontaneous parametric down-conversion (SPDC) to generate an autocorrelation signal for UV-pulses in the infra-red. Our method relies on the nth order emission of the SPDC process, emitting 2n photons with a rate approximately proportional to Pn for low pumping powers P. This allows one to obtain the nth order autocorrelation by simply counting the 2n down-converted photons. Herewith the first direct measurement of 180 fs ultra-short pulses, centred around 390 nm, inside an enhancement cavity becomes feasible.