Abstract: In this study, the carbon fiber reinforced polyetheretherketone composite (CF/PEEK) was used as a test sample to study the optical behavior of laser irradiated carbon fiber composites. The reflectance of the sample as a function of wavelength and angle of incidence was measured by an integrating sphere experiment. A laser beam reflection experiment was carried out to observe the behavior of the macroscopic reflection pattern as a function of the incident angle of the light and the angle of the sample. The microscopic behavior between the laser and the sample was analyzed, and the reflection process was simulated by optical design software. The integrating sphere experiment shows that the reflectance of the sample becomes larger as the wavelength increases, and becomes smaller as the incident angle increases. Macroscopic reflection experiment shows that the incident angle of light and the off-angle of the sample have a great influence on the reflection pattern. The reflection behavior is mainly dominated by the specular reflection of the surface fibers, and the simulation results are basically consistent with the experimental results. Based on the Fresnel equation, the effective refractive index of the sample fitted according to the least squares method is n=2.26.

Key words: carbon fiber composite, laser processing, CF/PEEK, integrating sphere experiment, reflectivity, effective refractive index, simulation