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Q: Quantenoptik und Photonik

Q 14: Optische Messtechnik

Q 14.7: Vortrag

Dienstag, 23. März 2004, 12:30–12:45, HS 204

Electrical control of holographic lenses exploiting the technique of electric field multiplexing — •Poonam Arora^1,2, Victor Petrov¹, Jürgen Petter¹, Kehar Singh², and Theo Tschudi¹ — ¹Institut für Angewandte Physik, TU-Darmstadt, D-64289 Darmstadt — ²Department of Physics, Indian Institute of Technology, New Delhi-110016

The Bragg condition for volume holograms in electro-optic crystals can be controlled by applying an external electric field to the recording material, which induces change in the average refractive index of the material via the electro-optic effect. This results in a strong electric field selectivity and provides the possibility to record and retrieve several holograms in the same volume of the material. This technique of Electric Field Multiplexing can be used e.g. for optical memory systems or the electrical control of the Transfer Function of Optical Filters. In our presentation, we will demonstrate the switching of holographic lenses with different focal lengths. Each hologram was recorded in LiNbO3 at an appropriate external electric field in counterpropagating geometry. To switch on a particular hologram, one has to merely apply the specific electric field. The advantage of this technique is that the switching time depends just on the resources and potentiality to apply the external electric field to the material. According to our estimations it could be up to nanoseconds. We will present the theory and experimental results and discuss possible applications.