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High performance optical shutter design with scalable aperture

100%

Pokryszka P. , Wośko M. , Kijaszek W. , Paszkiewicz R.

Bulletin of the Polish Academy of Sciences. Technical Sciences

2021

tom Vol. 69, nr 5

art. no. e138236

In this paper, design, construction and switching parameters of a self-made optical shutter with scalable aperture were reported. The aim of the study was to obtain the shortest possible switching times, minimum shutter open time and comparable with commercial shutter, the switch-on and switch-off times. For this purpose, numerical simulations were performed using Comsol Multiphysics 5.4. The design of the shutter and the control system have been optimized accordingly to the obtained results of numerical simulations. The optimized design was fabricated in a professional mechanical workshop and operational parameters of the constructed device were investigated. The switching parameters of the shutter, such as opening time, closing time, minimum shutter open time and other parameters were measured. The values of the parameters were determined from a statistical analysis of a sample consisting of 10,000 measurement results. The performed characterization showed that the tested device has the opening time of 0.8 ms, while the closing time is approximately 1 ms. The designed device is characterized by the minimum shutter open time of 6.4 ms.

Analysis of the impact of post-process modifications on the properties of TiO2 thin films with high-temperature stable anatase phase deposited by the electron beam evaporation method

75%

Obstarczyk A. , Mańkowska E. , Weichbrodt W. , Kapuścik P. , Kijaszek W. , Mazur M.

Opto-Electronics Review

2024

tom Vol. 32, No. 4

art. no. e151991

The paper describes the structural, optical, tribological, and mechanical properties of as‑prepared and annealed titanium dioxide (TiO₂) coatings. TiO₂ films were deposited by the electron beam evaporation (EBE) and additionally annealed at a temperature up to 800 °C using a tubular furnace. X-ray diffraction (XRD) analysis identified the amorphous phase of coatings as-prepared and annealed at 200 °C. The phase transition to anatase occurred at 400 °C, while annealing at 600 °C and 800 °C did not induce a phase transition to the rutile phase. The crystallite size increased with an annealing up to 40.4 nm at 800 °C. Raman spectroscopy confirmed the anatase phase in thin films annealed at 400 °C and above. A scanning electron microscope (SEM) images revealed surface morphology and grain structure changes after post-process high-temperature annealing. The optical transmission measurements showed a redshift in the fundamental absorption edge with increasing annealing temperature, accompanied by a decreased transparency level. The value of an optical band gap energy (Egopt) decreased to 2.77 eV for films annealed at 800 °C. Tribological tests revealed reduced scratch resistance with higher annealing temperatures, which was attributed to increased surface roughness and coating removal. Nanoindentation measurements showed a decrease in hardness with annealing temperature, attributed to changes in crystallite size and surface morphology. This comprehensive analysis of TiO₂ thin-film coatings showed that the post-process annealing should be carefully controlled for films used in optoelectronic applications.