Browsing by Subject "Mid-infrared optics"

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Open Access
In-chip microstructures and photonic devices fabricated by nonlinear laser lithography deep inside silicon
(Nature Publishing Group, 2017) Tokel, O.; Turnalı, A.; Makey, G.; Elahi, P.; Çolakoǧlu, T.; Ergeçen E.; Yavuz, Ö.; Hübner R.; Borra, M. Z.; Pavlov, I.; Bek, A.; Turan, R.; Kesim, D. K.; Tozburun, S.; Ilday, S.; Ilday, F. Ö.
Silicon is an excellent material for microelectronics and integrated photonics 1-3, with untapped potential for mid-infrared optics 4 . Despite broad recognition of the importance of the third dimension 5,6, current lithography methods do not allow the fabrication of photonic devices and functional microelements directly inside silicon chips. Even relatively simple curved geometries cannot be realized with techniques like reactive ion etching. Embedded optical elements 7, electronic devices and better electronic-photonic integration are lacking 8 . Here, we demonstrate laser-based fabrication of complex 3D structures deep inside silicon using 1-μm-sized dots and rod-like structures of adjustable length as basic building blocks. The laser-modified Si has an optical index different to that in unmodified parts, enabling the creation of numerous photonic devices. Optionally, these parts can be chemically etched to produce desired 3D shapes. We exemplify a plethora of subsurface - that is, 'in-chip' - microstructures for microfluidic cooling of chips, vias, micro-electro-mechanical systems, photovoltaic applications and photonic devices that match or surpass corresponding state-of-the-art device performances.
Open Access
Recent progress in germanium-core optical fibers for mid-infrared optics
(Elsevier, 2020) Ordu, Mustafa; Basu, S. N.
The search for low-loss and robust optical fibers in the infrared spectrum has always been an important research topic for many investigators. Over the years, fibers of various materials groups have been proposed to obtain ‘the ultimate infrared fiber’. Recently, a new competitive alternative has emerged: the semiconductor-core glass-cladded optical fibers. The excellent bulk materials properties and integrated circuit applications reveals the potential of semiconductors as fiber materials. One of the important photonic materials that has been proposed as a fiber-core material is germanium. In this paper, the development of Ge-based fibers and their optical properties in the mid-infrared spectrum are discussed. The performance of Ge-based fibers has been compared with other semiconductor-core fibers. Recent developments in the area of semiconductor fibers and the future prospects of semiconductors as infrared fiber materials are also discussed.