Evaluating the performance of cutting-edge UV gratings for NASA's next-generation space telescopes

UV spectroscopy is vital for many areas of astronomy, from studying galaxy evolution to evaluating the potential habitability of exoplanets. However, advanced grating fabrication techniques are essential to achieve the required performance for next-generation UV spectrographs, as current technologies are limited in both efficiency and resolution at UV wavelengths. This thesis provides an overview of existing UV grating fabrication techniques, along with promising methods such as electron-beam lithography and KOH-etching, which offer high-fidelity groove placement and enhanced spectral efficiency. To optimize grating design, I developed an algorithm that explores a broad parameter space to determine ideal grating prescriptions. I present the results of two pilot studies with differing design constraints, each focused on assessing exoplanet habitability via transit spectroscopy. Directly measuring gratings’ UV performance is time- and resource-intensive; however, evaluating a grating’s fabrication quality through interferometric and single-point metrology measurements is a comparatively faster and less expensive process. My thesis work will investigate whether trends found between measured UV grating performance of small-format gratings and the grating’s intrinsic fabrication characteristics can be leveraged to predict the performance of larger, future UV gratings. Quantifying the relationship between a grating’s UV performance and its optical and metrology characteristics will streamline the process of grating characterization for future UV missions, a vital tool that saves the community time and money as we work toward creating high- performance, blazed UV gratings for NASA’s next-generation space telescopes.