Research on Optical Properties and Micro-processing Characteristics of Collodion Thin Film

Colorless and transparent thin films of collodion are prepared on silicon wafers and K9 optical glass substrates by using spin-coating technique. The visible light transmittance, IR absorption spectra and optical constants of collodion thin film are measured by UV-3501 Spectrophotometer, Fourier transform infrared spectrometer (FTIR) and spectroscopic ellipsometry. The measured results show that its average visible light transmittance is 91.9%, and its average infrared absorptivity is better than 0.69/um. In the visible light region, the refractive index of collodion thin film changes in the range of 1.5–1.53, which accords with normal dispersion. The collodion films are etched using oxygen gas plasma. The surface morphology and thickness of etched thin film are measured by the polarizing microscope and MP-100S thickness measurement system, respectively. The results show that the collodion thin film is etched out in the oxygen gas plasma.