ILLIAS

Development of gas detection sensors using mutual injection in ICLs optical sources of mid-infrared light

PROJECT CODE: Τ2ΔΓΕ-0822

Since many molecules possess their specific spectroscopic fingerprint in the mid-infrared (MIR) wavelength regime, MIR absorption spectroscopy is a powerful technique to determine the composition and species concentration of an unknown substance. Due to the broad MIR-wavelength operation regime from 2.63 μm up to 355 μm, the high quantum efficiency and the customizable output wavelength, Quantum Cascade Lasers (QCLs) for the first realized technologically in 1994, have fertilized tunable diode laser absorption spectroscopy (TDLAS) and other interesting spectroscopy paradigms in the mid-infrared. Even if QCLs seem to be optimum laser choice regarding its performance within the framework of a wide variety of spectroscopic techniques, very recently, the so-called interband cascade laser (ICL) is entering the spectroscopy business with comparable and even superior performances with respect to wavelength, optical power and power consumption. The principal objective of ILLIAS is to exploit the advanced properties and the commercialization potential of ICLs in a novel direct absorption concept recently presented in the MIR with the use of QCLs by members of the consortium. The scheme exploits the properties of two mutually coupled MIR ICLs. Mutual optical coupling of two lasers refers to the nonlinear injection locking configuration where the optical coupling under appropriate conditions represents the stability of the coupled laser system. The introduction of an absorption cell into the mutual coupling path affects the optical coupling strength which can be utilized for sensitive spectroscopic measurement with enormously boosted sensitivity.