The Effects of Initial Laser Intensity on the Nonlinear Optical Properties of The Laser Dye DQOCI Doped Films Using Z-Scan Technique

Authors

  • Amal F. Jaffar Institute of Medical Technology/Al-mansoor, Medical Technical University, Baghdad, Iraq.

DOI:

https://doi.org/10.24996/ijs.2020.61.10.11

Keywords:

Nonlinear Optical Properties, Dye Doped Polymer Films, Z-Scan Technique

Abstract

This study is dedicated to investigate the effects of initial laser intensity on the nonlinear optical properties of the laser dye DQOCI dissolved in methanol with a concentration of 10 -5 M and doped with PMMA film. The properties were studied by using open and closed aperture Z-scan technique, with different levels of initial intensity (I0), excited by continuous diode solid-state laser at a wavelength of 532 nm. Three lenses of different focal lengths were employed to change the radius of the Gaussian laser beam and then change the initial intensity. For I0= 6.83 and 27.304 kWatt/cm2, the Z-scan curves show a saturation of absorption (SA) known as the negative type of nonlinearity, in which the absorption coefficient β 2 decreases and the transmittance increases with increasing the initial laser intensity. With I0 equal to 3.03 KWatt/cm2, the nonlinear absorption changes from SA to RSA, where the transmittances is reduced with the increase of intensity (z0) as analyzed by the theory of free carrier nonlinearities. The closed aperture z-scan shows a pre-focal transmittance minimum (valley) and a post focal transmittance maximum (peak) which reflects the z-scan signature of a positive nonlinearity (self-focusing) due to Kerr effect. Each of nonlinear refractive index (n2), nonlinear absorption coefficient (β 2), and third-order nonlinear optical susceptibility (χ3) are intensity-dependent.

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Published

2020-10-28

Issue

Section

Physics

How to Cite

The Effects of Initial Laser Intensity on the Nonlinear Optical Properties of The Laser Dye DQOCI Doped Films Using Z-Scan Technique. (2020). Iraqi Journal of Science, 61(10), 2551-2561. https://doi.org/10.24996/ijs.2020.61.10.11

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