Waveguide-integrated mid-infrared photodetection using graphene on a scalable chalcogenide glass platform.
basic_science · Level V
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- Record sourced from PubMed, PMID 35798746.
- Also identified by DOI 10.1038/s41467-022-31607-7 and PMC identifier 9262905.
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Abstract
The development of compact and fieldable mid-infrared (mid-IR) spectroscopy devices represents a critical challenge for distributed sensing with applications from gas leak detection to environmental monitoring. Recent work has focused on mid-IR photonic integrated circuit (PIC) sensing platforms and waveguide-integrated mid-IR light sources and detectors based on semiconductors such as PbTe, black phosphorus and tellurene. However, material bandgaps and reliance on SiO<sub>2</sub> substrates limit operation to wavelengths λ ≲ 4 μm. Here we overcome these challenges with a chalcogenide glass-on-CaF<sub>2</sub> PIC architecture incorporating split-gate photothermoelectric graphene photodetectors. Our design extends operation to λ = 5.2 μm with a Johnson noise-limited noise-equivalent power of 1.1 nW/Hz<sup>1/2</sup>, no fall-off in photoresponse up to f = 1 MHz, and a predicted 3-dB bandwidth of f<sub>3dB</sub> > 1 GHz. This mid-IR PIC platform readily extends to longer wavelengths and opens the door to applications from distributed gas sensing and portable dual comb spectroscopy to weather-resilient free space optical communications.