Talbot lithography and its application to the realisation of a cross-echelon spectrometer

Over the course of 150 years, optical spectroscopy has gradually opened up fields of application ranging from basic science to industrial measurement technology. This diversity has led to a specialisation of available measuring instruments for individual applications. However, there are still gaps in the area of some field applications, where adverse environmental conditions on site as well as high equipment costs force the acquisition of measured values in a central analysis laboratory. This usually means a limitation to random samples and a time-delayed measurement result, which is only of limited use for process control. The present work proposes a new variant of the Echelle spectrometer for the field of atomic emission spectroscopy: By integrating the two dispersion steps, which are realised with two separate elements according to the state of the art, into a single diffraction grating, the device design can be significantly simplified and miniaturised. Potentially, this increases robustness and lowers manufacturing costs. The focus of the work is to evaluate the concept of cross-echelon spectrometers in comparison to typical compact spectrometers. Special attention is paid to parameters such as spectral resolving power and diffraction efficiency. The advantages and disadvantages of different grating fabrication technologies are discussed. For the experimental proof of principle, a cross-echelon grating is fabricated and a prototype spectrometer is designed and realised. The latter is tested by means of practical example measurements and optimisation potentials are identified. The cross-echelon grating to be manufactured as a core component is characterised by the superposition of a very deep and coarse structure with a relatively shallow and fine structure. Conventional grating production methods fail here, so that an alternative process is used in the form of Talbot lithography. A modular and flexible exposure set-up is described for this, together with the associated software infrastructure, so that customised profile shapes can be produced. Furthermore, the imaging errors of the Talbot effect are analysed in detail and their minimisation possibilities are shown. The transmission of statistical defects in Talbot lithography is also investigated and optimisation options are derived.