Photonics for climate: nanophotonic instruments to analyse the atmosphere

Climate change is one of the most pressing problems of our time. In order to better understand and regulate these processes, we must be able to measure the composition of the atmosphere at any place and at any time. Above all, the quantitative measurement of trace gases such as CO2, nitrogen oxides, water vapour and methane is a major metrological challenge that can only be solved by high-performance spectrometers, such as those used in ESA's Sentinel programme. Nanostructured gratings and complex setups with gratings form the heart of the instruments. Using the ESA mission CO2m as an example, I discuss Jena's contribution to optical instruments and show that large, lithographic structures that enable the control of light on the scale of nanometres are a key element for modern high-performance optics.