Fibre laser based mid infrared source development

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Gas molecules exhibit characteristic vibrations that lead to highly structured but characteristic light absorption spectra in the mid-infrared (mid-IR) regions of the electromagnetic spectrum. Consequently, by measuring the absorption of light through a gas sample as a function of the wavelength the presence and concentration of different molecular species within the sample can be determined. This is enabling for a wide range of sensing applications in biology, medicine, environmental monitoring and manufacturing amongst others. In order to exploit this sensing approach there is an emerging requirement for laser sources operating in the mid-IR. These are difficult to realise using traditional laser materials and designs. In this project we will develop a range of mid-IR sources offering unprecedented levels of wavelength coverage and power within the mid-IR (wavelengths range from 2-15 um where the "fingerprint" absorption spectra of most gases can be detected).The project will involve the development of high power short pulse fibre lasers operating at conventional near-IR wavelengths (e.g. 1 and 2um) and converting the wavelength of the output light to the mid-IR wavelengths using nonlinear optical effects in specially engineered crystals, and/or optical fibres. We will target both high-power sources with a wide wavelength tuning range and a narrow spectral linewidth that can be used to probe individual gas absorption, as well as broadband supercontinuum sources with ultrahigh spectral power densities that can be used to record the full gas absorption spectra in one measurement without tuning.The ultimate goal of the project is to develop a ground-breaking new technology platform for the mid-IR and to work with others to demonstrate the enabling capabilities provided by the platform in several of the important application areas above, with a particular focus on the life sciences.