Nonlinear optical characteristics of self-assembled films of ZnO
- First Online:
- Cite this article as:
- Irimpan, L., Deepthy, A., Krishnan, B. et al. Appl. Phys. B (2008) 90: 547. doi:10.1007/s00340-007-2886-1
- 223 Downloads
In the present work, we have investigated the nonlinear optical properties of self-assembled films formed from ZnO colloidal spheres by z-scan technique. The sign of the nonlinear component of refractive index of the material remains the same; however, a switching from reverse saturable absorption to saturable absorption has been observed as the material changes from colloid to self-assembled film. These different nonlinear characteristics can be mainly attributed to ZnO defect states and electronic effects when the colloidal solution is transformed into self-assembled monolayers. We investigated the intensity, wavelength and size dependence of saturable and reverse saturable absorption of ZnO self-assembled films and colloids. Values of the imaginary part of third-order susceptibility are calculated for particles of size in the range 20–300 nm at different intensity levels ranging from 40 to 325 MW/cm2 within the wavelength range of 450–650 nm.