In this contribution, the photoluminescence, time-resolved luminescence and luminescence kinetics of α'-Sr2SiO4:Eu(2+) are studied. The luminescence of Sr2SiO4:Eu(2+) consists of two broad bands, peaked at 490 nm (blue-green) and 570 nm (yellow-orange), which originate from two luminescence centers, related to Eu(2+) in ten-coordinated SI and nine-coordinated SII sites, respectively. Based on spectroscopic data the energetic structure of Sr2SiO4:Eu(2+) has been developed, which includes the bands edges, energies of Eu(2+) in the SI and SII sites and energies of strontium and oxygen vacancies. To investigate the long-lasting luminescence phenomenon in Sr2SiO4:Eu(2+) the temperature influence on the time evolution of luminescence was analyzed. It has been found that the long-lasting luminescence is related to the Eu(2+) in SII site. The shallowest traps responsible for emission decaying within a few seconds are tentatively attributed to the [Eu(3+)(SII)-[Formula: see text]] centers. The depth of traps responsible for the long-lasting luminescence observed at room temperature has been estimated as equal 0.73 eV.
The fabrication processes for silicon nitride photonic integrated circuits evolved from microelectronics components technology—basic processes have common roots and can be executed using the same type of equipment. In comparison to that of electronics components, passive photonic structures require fewer manufacturing steps and fabricated elements have larger critical dimensions. In this work, we present and discuss our first results on design and development of fundamental building blocks for silicon nitride integrated photonic platform. The scope of the work covers the full design and manufacturing chain, from numerical simulations of optical elements, design, and fabrication of the test structures to optical characterization and analysis the results. In particular, technological processes were developed and evaluated for fabrication of the waveguides (WGs), multimode interferometers (MMIs), and arrayed waveguide gratings (AWGs), which confirmed the potential of the technology and correctness of the proposed approach.
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