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Q: Fachverband Quantenoptik und Photonik

Q 15: Poster 1: Quanteninformation, Quanteneffekte, Laserentwicklung, Laseranwendungen, Ultrakurze Pulse, Photonik

Q 15.56: Poster

Montag, 14. März 2011, 16:30–19:30, P1

Intracavity absorption spectroscopy with an Er³⁺-doped fiber ring laser — •Peter Fjodorow, Luis Leal, Benjamin Löhden, Klaus Sengstock, and Valeri Baev — Institut für Laser-Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg

Laser intracavity absorption spectroscopy is a very effective way to enhance the sensitivity of absorption measurements. With this technique, a sample of narrow-line absorption is placed into the cavity of a broadband laser, e.g. a fiber laser. The laser light passes through the absorber many times, and the absorption signal appears in the output spectrum, as in a multipass cell. The highest sensitivity is achieved with a cw laser, and it is limited by nonlinear mode coupling. e.g. by the spatial inhomogeneity of the laser gain and by stimulated Brillouin scattering. We report here on an experimental setup for sensitive absorption measurements based on a broadband Er³⁺-doped fiber unidirectional ring laser. In this laser the complete elimination of the spatial gain inhomogeneity, reduction of stimulated Brillouin scattering in the fiber and decrease of spectral noise has been demonstrated. The sensitivity achieved with this laser is approximately one order of magnitude higher compared to the linear laser configuration with similar parameters [1] and corresponds to the effective absorption path length of over 500 km. This system can be used for the detection of trace gases and for environmental or medical applications.

[1] B. Löhden, S. Kuznetsova, K. Sengstock, V. M. Baev, A. Goldman, S. Cheskis, and B. Pálsdóttir, Appl. Phys. B, DOI 10.1007/s00340-010-3995-9 (2010).