iHWG-ICL: Methane Sensing with Substrate-Integrated Hollow Waveguides Directly Coupled to Interband Cascade Lasers

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• 作者：Erhan Tütüncü ; Markus Nägele ; Peter Fuchs ; Marc Fischer ; Boris Mizaikoff
• 刊名：ACS Sensor
• 出版年：2016
• 出版时间：July 22, 2016
• 年：2016
• 卷：1
• 期：7
• 页码：847-851
• 全文大小：394K
• ISSN：2379-3694

文摘

The development of a compact iHWG-ICL gas sensor combining innovative substrate-integrated hollow waveguides (iHWG) with mid-infrared emitting type-II interband cascade lasers (ICL) is presented. Hence, tunable laser absorption spectroscopy (TLAS) with iHWGs in direct absorption mode is enabled. Using a room-temperature distributed feedback (DFB) ICL emitting at approximately 3.366 μm, quantitative sensing of methane was demonstrated. Wavelength scanning was obtained via current tuning for monitoring an isolated line in the v3 fundamental band of CH₄. The obtained spectra were compared to calculated spectra derived from the HITRAN2012 database. Furthermore, the performance of iHWGs simultaneously serving as miniaturized gas cell and as efficient optical waveguide at various absorption path lengths was tested and optimized. Calibration functions in the concentration range of 50 to 400 ppm_v were established enabling limits of detection ranging from 6 to 28 ppm_v. Hence, the combination of iHWGs with ICLs facilitates a new generation of compact optical sensor devices for rapid gas diagnostics in low sample volumes.