THE MID-INFRARED (MIR) REGION
The MIR region of the electromagnetic spectrum is attractive for a very broad range of applications, which stem from the overlap with the two widest atmospheric transmission bands (3-5μm, 7-12μm), like thermal imaging and molecular sensing. Absorption based spectroscopy techniques provide a method for detecting such molecules with high sensitivity and specificity and can thus be employed e.g. for biomedical applications, to monitor the composition of gas/liquid mixtures in industrial processes, or to identify trace components down to extremely low concentrations for purity analysis, environmental monitoring and security applications.
ACCESSING THE MIR REGION - A TECHNOLOGICAL BOTTLENECK
The MIR applications mentioned above require optical devices operating at wavelengths currently non accessible. Most common optical laser sources and detectors operating today in the NIR and MIR rely on technologies where the emission wavelengths are inherently set.
A powerful and versatile solution for accessing MIR wavelengths consists in exploiting optical nonlinear interactions in a nonlinear medium to convert one or more input wavelengths into new ones. The concept is well known and has been exploited in bulk nonlinear crystals and silicon waveguide platforms for frequency conversion. As an alternative nonlinear medium, glass optical fibre platform presents several advantages over these two former platforms thanks to its versatility, lightweight and compact format which naturally lends itself to an all-fibre architecture with no moving parts nor alignments needed.
In recent years, the reliability of silica glass fibre technology has allowed significant achievements in the NIR, such as coherent Supercontinuum Generation (SCG), generation of quantum correlated photon pairs, fibre optical parametric oscillators and amplifiers or frequency comb generation. However, because of its poor transparency for wavelengths above 2.5 μm, silica glass is not suitable for MIR applications and alternative glass systems with a suitable MIR transparency and higher nonlinearity must be used.
OVERALL OBJECTIVE
To develop a novel optical fibre technology that will enable the development of versatile MIR sources through the exploitation of nonlinear effect in optical fibre. It will enable the development of cost effective and efficient MIR sources and detectors with a range of specifications best adapted to applications having important social repercussions such as the development of devices for early diagnosis and point-of-care, remote sensing, or security instruments.
