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DF: Fachverband Dielektrische Festkörper

DF 13: Poster II

DF 13.21: Poster

Mittwoch, 28. März 2012, 15:00–17:30, Poster E

Light-induced linkage isomerization by ultrafast mid-infrared spectroscopy in sodium nitroprusside on the 100 fs time domain — •Felix Freytag, Kristin Springfeld, Volker Dieckmann, and Mirco Imlau — Department of Physics, University of Osnabrück, Germany

Today‘s information storage and telecommunication industry strongly demands for novel devices to increase storage densities and transmission speed in optical networks. A promising approach is the control of light by light using molecular compounds offering ultrafast photochromism and -refraction on the sub-ps time scale. Nitroprusside compounds have been shown to allow for these features based on a light-induced linkage isomerization [1]. Recently, its time constant has been reported to be less than 200 fs by means of VIS-pump-probe technique [2]. However, such structural alterations have not been proven in the compound by direct measurements on the sub-ps time scale. For studying selected vibrational modes at ν≈1950 cm⁻¹ of sodium nitroprusside, we use frequency-resolved infrared spectroscopy. The transmission of mid-infrared τ≈150 fs pulses is detected by a multichannel MCT detector as a function of time delay to an intense VIS pump pulse of τ≈100 fs duration. We will present first results on our studies of the light-induced changes of such vibrational modes on the 100 fs time scale. Financial support by the DFG (IM 37/5, INST 190/137-1) and the DAAD (50445542) is gratefully acknowledged.

[1] Imlau et al., Appl. Phys. B, 68, 877 (1999)

[2] Schaniel et al., Phys. Chem. Chem. Phys., 12, 9029 (2010)