The aims of thesis was study the spectral properties of natural organic dyes (carrot and beetroot dyes indifferent concentrations ,Study the effect of solvent (methanol, distilled water) on dye ,Study the linear and nonlinear optical properties of the beetroot dye liquid medium by using z-scan technique and testing the samples an optical limiter device.

This study investigates the extraction and optical characterization of environmentally friendly natural dyes derived from carrot and beetroot using methanol and distilled water as solvents. The extraction was performed using a Soxhlet apparatus for 8 h at 60 °C, followed by a 72 h aging process, with various volumetric ratios prepared (pure, 2:2, 2:4, 2:6, 2:8, 2:10). UV–Vis spectrum analysis revealed maximum  wavelengths absorption at 315 nm and 480 nm for carrot and beetroot, respectively, with minimum transmittance at 35%  and  31%. The beetroot dye exhibited optimum performance at a volumetric ratio of 2:8, showing a fluorescence peak at 737 nm and a significant red shift of   257 nm, indicating enhanced stability. The linear optical parameters at this concentration were: refractive index (n = 1.0496), bandgap energy (Eg = 2.58eV), extinction coefficient (k= 0.045). Nonlinear optical properties were evaluated using the Z-scan technique, revealing a nonlinear refractive index (n₂ = 2.83 × 10⁻⁶), nonlinear absorption coefficient (β = 0.015), and third-order susceptibility (χ³ = 205 × 10⁻⁶) at a volumetric ratio of  (2:8). These results demonstrate that beetroot dye possesses significant linear and nonlinear optical properties, making it a promising candidate for photonic applications, optical limiting devices, and laser protection systems.

The most important recommendations which the study has come up with and the average obtained:

1. The most important recommendations which the study has come up with: 1 Extract natural dyes from other plant sources such as pomegranate and orange peels and study their optical properties. These can be compared with beetroot dye.
2. 2.Doping dyes with polymeric materials and converting them into thin films for use in optical applications.
3. 3.Investigate adding nanomaterials to the extracted dyes to enhance optical efficiency.         Their effect on linear and nonlinear optical properties can also be studied.
4. 4.Investigate the extraction of carrot dye using non-polar solvents such as hexane and evaluate their efficiency in extracting β-carotene. The optical properties of the extracted dye can also be compared with those obtained using other solvents.