Indian Journal of Science and Technology
Year: 2009, Volume: 2, Issue: 8, Pages: 27-31
R.K. Rekha and A. Ramalingam
Centre for Laser Technology, Department of Physics, Anna University, Chennai-600025, India
*Author for the correspondence:
Centre for Laser Technology, Department of Physics,
Anna University, Chennai-600025, India
E-mail: [email protected]
Thermally induced optical nonlinearity of carmine dye in methanol is studied using a CW Nd-YAG laser at 532 nm as the source of excitation, both in solution and solid film (Methylmethacrylate- MMA), respectively. The optical response is characterized by measuring the intensity dependent refractive index (n2) of the medium using the Z-scan technique. The dye exhibited a negative (defocusing) nonlinearity and large nonlinear refractive index of the order of 10−7 cm2 /W. The nonlinear refractive index was found to vary with concentration. The third-order nonlinearity of the dye was dominated by nonlinear refraction, which leads to strong optical limiting of laser. The result reveals that carmine dye can be a promising material for optical limiting applications.
Keywords: Z-scan, carmine dye, NLO properties, optical limiting
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