Robust optimization of single-cycle THz setups based on phase-matching via tilted pulse fronts using an incident-fluence metric

Abstract

Despite the popularity and ubiquitousness of the tilted-pulse-front technique for single-cycle terahertz (THz) generation, optimization of the experimental setup remains complex and difficult due to the sensitive dependence on and coupling between the optical pulse parameters, including fluence, beam size, angular dispersion and temporal compression. Here we present a systematic and robust method to tune the tilted pulse-front setup, based on use of selected multi-dimensional scans, which enables a straight-forward and accurate determination of optimum parameter values. Our methodology not only allows us to determine parameter sensitivities and achieve a robust optimum in the performance, but also enables a verification of certain physical properties of the lithium niobate prism, including the THz refractive index. The detailed step-by-step procedure is discussed and applied to a tilted-pulse-front THz setup at both room temperature and cryogenic temperatures. The procedure can be applied to any setup based on the tilted-pulse-front geometry and is important for the construction of high energy THz sources required for strong field terahertz applications such as novel particle acceleration schemes or beam manipulators.