Dresden 2006 – scientific programme

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DF: Dielektrische Festkörper

DF 11: Electric, Electromechanical and Optical Properties II

DF 11.4: Talk

Friday, March 31, 2006, 12:10–12:30, M{\"U}L Elch

Recording and Readout of Spatial Gratings with Femtosecond Laser Pulses* — •Dominik Maxein¹, Peter Reckenthäler¹, Oliver Beyer¹, Karsten Buse¹, Boris Sturman², Hung Te Hsieh³, and Demetri Psaltis³ — ¹Physikalisches Institut, Universität Bonn, Wegelerstr. 8, 53115 Bonn — ²Institute of Automation and Electrometry, Novosibirsk, Russia — ³Department of Electrical Engineering, California Institute of Technology, Pasadena, USA

Employing the pump-and-probe technique with short laser pulses it is possible to investigate physical processes on very short time scales. With holographic methods, one can detect small absorption and refractive index changes. It is therefore desirable to combine both kinds of measurements for the investigation of light-induced processes in materials. However, while the well-known coupled wave equations are applicable for continuous-wave light and long pulses, new aspects like the short pulse duration and geometry have to be taken into account. We present results of theoretical studies on recording of spatial gratings with two femtosecond laser pulses. Time resolved read out of resulting gratings is performed with a Bragg matched pulse at another wavelength. Instantaneous effects (Kerr effect, two-photon absorption) are taken into consideration as well as longer-lasting changes of the material due to the exposure (excitation of charge carriers). The predictions of our model are compared with results of experiments utilizing lithium niobate and calcium fluoride crystals as the recording material.

* Financial support by the DFG (award BU 913 / 13) and the Deutsche Telekom AG is gratefully acknowledged.