A STUDY OF SOME OPTICAL-PROPERTIES OF HAFNIUM DIOXIDE (HFO2) THIN-FILMS AND THEIR APPLICATIONS

By use of evaporation conditions adjusted for the deposition of hafniu m dioxide (HfO2), a series of films ranging in thickness from 50 to 10 000 nm was prepared by using an electron beam gun inside an evacuated coating chamber of pressure 1 x 10(-5) mbar. The films were obtained o n optical glass substrate by using oxygen with a backfill pressure of 2.4 x 10(-4) mbar during the deposition processes. The optical constan ts of the films were computed in the spectral wavelength region (350-2 000 nm) from the transmission, reflection and thickness measurements. A computer program was created to determine two optical parameters n a nd k of the films, and this was achieved by entering the practical res ults into the computer program, which solved a series of equations for each wavelength. The effects created by changing various evaporation conditions (thickness, substrate temperature and evaporation rate) wer e studied in the spectral wavelength range, and the optimum values of the various conditions were obtained while achieving the best optical performance. According to the investigations of the HfO2 material, two applications of the anti-reflection (AR) multi-layer coatings were ac hieved in two different spectral wavelength ranges. The first applicat ion was measured in the visible and near infra-red (VIS/NIR) range fro m 500 nm to 850 nm deposited on the glass substrate. The second applic ation was measured in the infrared (IR) range from 7500 nm to 11500 nm deposited on germanium substrate. Computer modelling for designing th e optical multi-layer system has been presented. The theoretical formu lation and experimental results with the same specification were achie ved. The correlation between the theoretical and the experimental resu lts reveals a close agreement that offers a convenient method for pred icting and controlling the multi-layer coating. By continuous measurem ent of the optical and mechanical (durability) performances of the coa ting process, high-quality films were produced in the manufacture of v arious optical devices.