Abstract
The first combination of mid-infrared (MIR) tunable quantum cascade lasers (tQCLs) with thin-film diamond strip waveguides (DSWGs) suitable for advanced chemical sensing/biosensing is demonstrated. The sensing system is composed of thin diamond films grown on surface-passivated Si wafers via chemical vapor deposition (CVD) and microstructured using inductively coupled plasma (ICP) etching, serving as photonic waveguides for radiation emitted by a broadly tunable quantum cascade laser (tQCL) in the spectral regime of 5.78-6.35 μm (1570-1730 cm-1). The characterization of the free-standing diamond waveguides reveals excellent transmission properties across a broad MIR band. As a proof of concept, the detection of acetone in D2O via evanescent field absorption is demonstrated achieving a limit of detection (LOD) as low as 200 pL, which indicates a significant sensitivity improvement compared to conventional MIR slab/strip waveguides reported to date. Providing characteristic absorption features within the tuning range of the tQCL, studies using anisaldehyde as an analyte further corroborate the potential of tQCL-DSWG-based chemical sensors/biosensors.
Original language | English |
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Pages (from-to) | 8136-8141 |
Number of pages | 6 |
Journal | Analytical Chemistry |
Volume | 86 |
Issue number | 16 |
DOIs | |
Publication status | Published - 19 Aug 2014 |
Externally published | Yes |