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Fabrication of optically anisotropic structures in amorphous silicon films using femtosecond laser pulsesтезисы доклада Тезисы
- Авторы: Zabotnov S.V., Shuleiko D.V., Kuzmin E.V., Pakholchuk P.P., Volkovoynova L.D., Serdobintsev A.A., Kashkarov P.K.
- Сборник: Book of Abstracts of VIII International Conference on Ultrafast Optical Science «UltrafastLight-2024»
- Тезисы
- Год издания: 2024
- Место издания: ФИАН, Москва
- Первая страница: 84
- Аннотация: Advanced technologies of photonics and microelectronics make it possible to design compact planar elements for integrated photonic circuits based on silicon. Femtosecond laser pulses irradiation of thin silicon films might provide both crystallization and surface texturing which consists in fabrication of laser-induced periodic surface structures (LIPSSs).In our work, we fabricated large area LIPSSs (up to 5x5 mm2) in the amorphous silicon thin films and studied Raman and reflectance spectra at various incident light polarizations. Three types of samples were irradiated and examined: an amorphous silicon layer only, an amorphous silicon layer with a flexible polyimide underlayer, and an amorphous silicon layer with a 10 nm aluminum coating. The amorphous silicon layers have thicknesses of 1 μm.The samples were irradiated in the raster mode with femtosecond laser pulses generated by a Satsuma Amplitude Systems laser (300 fs, 515 or 1030 nm). LIPSSs were fabricated in all samples. The periods of the surface gratings obtained are close to the wavelengths used. The appearance of the LIPSSs is caused by photoinduced surface plasmon-polaritons generation and is confirmed by calculations with the Sipe–Drude theory.Raman spectroscopy data show partial nanocrystallization of the surface (up to 70%). The Raman spectra obtained are polarization-sensitive.Reflectance spectra for all samples were measured in the range of 1.5–18 μm for s- and p-polarizations. The measured spectra indicate the presence of dichroism in the irradiated samples. Its value reaches the maximum value of 0.12 μm-1. All the spectra are characterized by thin film interference. Analysis of interference maxima positions made it possible to find the refractive indices for the ordinary and extraordinary waves. The maximum birefringence value is 0.2 in the range of 1.9–2.7 μm.The Raman signal intensity and the dichroism value for various polarizations of the incident light are explained by a depolarization field contribution within the LIPSSs.Therefore, the silicon films with LIPSSs can be considered as a promising base to design planar devices which are sensitive to the incident light polarization.
- Добавил в систему: Заботнов Станислав Васильевич