Linear and nonlinear optical properties of potassium dichromate in solution and solid polymer film

A film with polyvinyl alcohol and aqueous solution of potassium dichromate are prepared where various linear optical constants and nonlinear properties are determined via the measurements of the film optical absorbance and transmittance spectra in the wavelength range 312–900 nm and via the diffraction ring patterns by transmitting a visible, 473 nm, continuous wave with single fundamental transverse mode, low power laser beam. As high as 10¹⁰ sec⁻¹ optical conductivity and nonlinear refractive index of 10⁻¹³ cm²/W of the film are obtained due to the linear parameters and 10⁻⁷ cm²/W of the aqueous solution due to the diffraction ring patterns. Fraunhofer approximations of the Fresnel-Kirchhoff theory are used to simulate the diffraction ring patterns