Hamburg 2009 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 29: Poster I

Q 29.8: Poster

Tuesday, March 3, 2009, 16:30–19:00, VMP 8 Foyer

A tunable laser source at 5.1 µm for precision spectroscopy of a rovibrational transition of cold HD⁺ ions — •U. Bressel, T. Schneider, S. Vasilyev, A. Yu. Nevsky, I. Ernsting, B. Roth, and S. Schiller — Institut für Experimentalphysik, Heinrich-Heine-Universität Düsseldorf

HD⁺ is the most simple heteronuclear molecule containing just a single electron. Precise measurements of its rovibrational transition frequencies can determine QED effects in molecules, the ratio m_e/m_p [1] and improve limits of its time-dependence [2]. For high-precision vibrational spectroscopy of the v=0 → v=1 fundamental vibrational transition a cw infrared laser tunable from 5.09 µm to 5.13 µm has been developed. It is based on difference frequency generation (DFG) between a 1064 nm Nd:YAG laser and a 1305 - 1350 nm external-cavity diode laser (ECDL). The nonlinear crystal is a periodic-poled MgO:LiNbO₃-crystal (PPLN), producing up to 0.6 µW at 5.115 µm. The frequency of the Nd:YAG laser is iodine stabilized. The frequency of the ECDL is stabilized via a temperature stabilized Invar cavity allowing a linewidth of about 100 kHz. The frequency of the 5 µm radiation will be determined by a simultaneous measurement of the frequency of each laser using a frequency comb.

[1] J. Koelemeij et al., Phys. Rev. Lett. 98, 173002 (2007)

[2] S. Schiller, V. Korobov, Phys. Rev. A 71, 032505 (2005)