Mid-IR emission from integrated rare earth (Dy3+, Pr3+)-doped chalcogenides waveguides for sensing applications

The mid-infrared (mid-IR) spectral region is of great interest to many areas of science and technology as it contains two important transparency windows (3-5 and 8-13 μm) of the Earth’s atmosphere and strong characteristic vibrational transitions displayed by a large number of molecules. Praseodymium (Pr³⁺) and dysprosium (Dy³⁺) ions feature characteristic transitions in the mid-IR and transmission range of chalcogenides-based materials spans a large part of the mid-IR. The combination of efficient waveguiding properties with mid-IR light emitters would therefore be a key enabler of the development of mid-IR sensors-on-a-chip for health, security and environmental applications. In this paper, RF magnetron co-sputtering is used to deposit a Dy³⁺/Pr³⁺-doped chalcogenides guiding layer based on the quaternary system composed of Ga, Ge, Sb and Se atoms on silica cladding layer. The fabrication process of straight ridge waveguides using photolithography and RIE/ICP dry etching is then described. Finally, Dy³⁺ and Pr³⁺ mid-IR guided photoluminescence around 2.5 and 4.5 μm is demonstrated at room temperature using co-propagating pumping at telecommunication wavelengths (respectively around 1.3 and 1.55 μm).