Paper A87

Background-free femtosecond autocorrelation in collinearly-aligned inverted field geometry using optical vortices

N. Dimitrov, M. Zhekova, Y. Zhang, G. G. Paulus, and A. Dreischuh,


Among the existing techniques for measuring ultrashort pulse durations, the two classical second-order methods – interferometric and the background-free autocorrelation – are distinguished due to their simplicity and reliability. In this work we report on a technique that allows realignment-free switching between these two modes of autocorrelation. It is based on a collinearly aligned inverted-field interferometer and an optical vortex plate that is added/removed in front of the device in order to switch between both modes. Experiment and theoretical modeling confirm the effectiveness of the technique down to the 10-fs range.