Study of the on – off – on dye doped nematic irradiation in a pump-probe experiment
M. C. VĂRUŢ1,*
Affiliation
- 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