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Register a new userStudy of SiO2-PbO-CdO-Ga2O3 glass system for mid infrared optical elements
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Ryszard Buczy\\'nski
Publication date
2020
fields
Physics
and research's language is
English
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Glasses based on SiO2-PbO-CdO-Ga2O3 system have been studied for the first time for fabrication of mid-infrared optical elements. Gallium oxide concentration was gradually increased, replacing silicon dioxide, for different cadmium and lead oxide content. The thermal and optical properties were investigated for different compositions. It was observed that the thermal stability, refractive index, and the transmission in the infrared range increased with increase of gallium and lead concentrations. The most thermally stable glass composition was selected for fabrication of optical elements such as optical fibers. We also successfully fabricated mid-infrared lenses by hot embossing for potential application in compact gas detectors
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We present high-reflectivity substrate-transferred single-crystal GaAs/AlGaAs interference coatings at a center wavelength of 4.54 um with record-low excess optical loss below 10 parts per million. These high-performance mirrors are realized via a novel microfabrication process that differs significantly from the production of amorphous multilayers generated via physical vapor deposition processes. This new process enables reduced scatter loss due to the low surface and interfacial roughness, while low background doping in epitaxial growth ensures strongly reduced absorption. We report on a suite of optical measurements, including cavity ring-down, transmittance spectroscopy, and direct absorption tests to reveal the optical losses for a set of prototype mirrors. In the course of these measurements, we observe a unique polarization-orientation-dependent loss mechanism which we attribute to elastic anisotropy of these strained epitaxial multilayers. A future increase in layer count and a corresponding reduction of transmittance will enable optical resonators with a finesse in excess of 100 000 in the mid-infrared spectral region, allowing for advances in high resolution spectroscopy, narrow-linewidth laser stabilization, and ultrasensitive measurements of various light-matter interactions.
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