Wide bandpass optical filters with TiO2 and Ta2O5

Abstract

Abstract:Complex multilayer thin film filters for optical applications have been designed, prepared and characterized in this work. E-beam reactive evaporation technique has been used as a deposition process. In the first stage, optimized individual film layers of TiO 2 , Ta 2 O 5 , and SiO 2 are deposited and characterized optically and structurally before the deposition of multilayered structures. The filter designs are based upon 33 layered SiO 2 /TiO 2 and SiO 2 /Ta 2 O 5 configurations on glass substrate. These designs are optimized to achieve wideband transmission in the visible spectrum. After deposition, the two filter configurations are characterized optically and structurally using spectrophotometery, atomic force microscopy (AFM), X-ray diffraction (XRD) and scanning electron microscopy (SEM). SiO 2 /Ta 2 O 5 /glass filter has been found sensitive to deposition conditions since high absorption is observed in multilayered configuration for the as-deposited samples. Post-deposition annealing of the filter in the temperature range 150 to 250˚C was also performed in order to study the effect of temperature on absorption and spectral characteristics of the filter. Comparison of the two filter configurations was also performed to analyze their suitability for optical applications. Adhesion of the two filters was found to be very good by means of tape-peel test. 42.79.Ci PACS (2008):

TiO2/SiO2 multilayer as an antireflective and protective coating deposited by microwave assisted magnetron sputtering

“…High refractive index of about 2.42 (l = 550 nm) in case of TiO 2 was found due to high energy deposi− tion process of microwave assisted magnetron sputtering. Similar value has been also obtained by others [2].…”

“…Based on recorded spec− tra, refractive index and extinction coefficient of single la− yers were estimated. Fitting of experimental results for TiO 2 and SiO 2 thin films were made using Drude -Lorentz dis− persion model and Powell's analysis method. Calculations were performed by using Pearson's test -c 2 (Chi−square).…”

“…Antireflective coatings (ARCs) are of great interest of a wide range of industries and applications especially including ophthalmics, optics, flexible displays, bio−engi− neering, energy generation, decorative and barrier coatings for pharmaceutical and food products [1][2][3][4]. Coatings made from thin films can modify electrical, mechanical and/or optical properties of a solid base material in a cost−effective way.…”

“…Coatings made from thin films can modify electrical, mechanical and/or optical properties of a solid base material in a cost−effective way. Some common examples are scratch−resistant coatings for spectacles, anti−reflective coatings for lenses and win− dows, transparent conducting coatings for flat−panel dis− plays and low−friction coatings for bearings [2,5,6].…”

Statistical Design Centering Optimization of 1d Photonic Crystal Filters

“…The dimensions of such devices are in nano-meters and parts of them reached the size of few atoms [17]. The target of optimization techniques is to suggest the numerical values of the parameters that lead to the best and optimum performance of the device or circuit.…”