Publisher DOI: | 10.1364/OL.44.000175 | Title: | Free-carrier detection in a silicon slab via absorption measurement in 2D integrating cells | Language: | English | Authors: | Fohrmann, Lena Simone Lotfi, Nima Alzein, Bilal Gaafar, Mahmoud Abdelazis Petrov, Alexander ![]() Eich, Manfred |
Issue Date: | 1-Jan-2019 | Source: | Optics Letters 1 (44): 175-178 (2019-01-01) | Abstract (english): | 2D integrating cells provide long optical path lengths on a chip by multiple reflections at highly reflective mirrors similar to integrating spheres in free space. Therefore, they build a promising platform for integrated optical absorption sensing. Here, we present first absorption measurements of free carriers generated by a modulated pump laser inside a 2D integrating cell in a silicon slab. The results can be used to evaluate the lifetimes of free carriers in silicon slabs for integrated optics. Employing a silicon-on-insulator platform with a silicon thickness of 220 nm, we demonstrate measurements of the access free-carrier concentration on the order of 1 − 8 · 10 15 cm −3 with lifetimes on the order of 0.1–1 μs governed by surface recombination at the silicon interfaces. The measured lifetimes are dependent on free-carrier concentration, which confirms previous observations. The presented free-carrier absorption experiment verifies the sensitivity of 2D integrating cells to changes in the absorption coefficient and thus demonstrates the potential of 2D integrating cells for absorption sensing. |
URI: | http://hdl.handle.net/11420/2111 | ISSN: | 0146-9592 | Journal: | Optics letters | Institute: | Optische und Elektronische Materialien E-12 | Document Type: | Article | Project: | Mid infrared gas sensing Relativistische photonische Bandlückenspiegel in der integrierten Optik |
Appears in Collections: | Publications without fulltext |
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