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Study of the on – off – on dye doped nematic irradiation in a pump-probe experiment

M. C. VĂRUŢ1,*

Affiliation

  1. Faculty of Mathematics and Natural Sciences, University of Craiova, 13 A. I. Cuza Str. Craiova, 200585, Romania

Abstract

The irradiation with an Ar  laser beam of the cells filled with 5CB doped with MR has been performed in a series of the type on – off – on in a pump-probe experiment. In the first period of irradiation the recorded probe signal of a He-Ne laser beam is quasi-constant at beginning of the time and then increased with the irradiation time. A jump and a delay were observed at the end of the first irradiation period. In the off period of irradiation the signal is quasi-constant. A jump and a delay were also observed at the second irradiation. These experimental results were explained based on the trans-cis and cis-trans isomerisation of the MR molecules and on the fact that the trans isomer has an absorbance for the red light (He- Ne laser) less than that corresponding to the cis isomer..

Keywords

Nematic liquid crystal, Azo-dye, Cis-trans transition.

Citation

M. C. VĂRUŢ, Study of the on – off – on dye doped nematic irradiation in a pump-probe experiment, Optoelectronics and Advanced Materials - Rapid Communications, 8, 7-8, July-August 2014, pp.747-750 (2014).

Submitted at: March 19, 2014

Accepted at: July 10, 2014