Construction and Characterization of an Interferometer for the Stabilization of Attosecond Experiments

Abstract: A new optical interferometer for delay stabilization in attosecond pump/probe experiments is constructed, featuring a custom-made hole-drilled recombination mirror and using a co-propagating HeNe laser for the interference. The interferometer is shown to generate an interference pattern of high enough contrast for delay stabilization. The stability of the measured delay is tested with the interferometer in the passively stable mode. The measured delay is shown to exhibit four curious characteristics: a rapid fluctuation with σ ≈ 0.85 fs, sudden jumps of 2-4 fs, oscillations with a period of ~1 hour and amplitude of ~4 fs, and a linear drift of varying magnitude. The rapid fluctuations are attributed to ambient vibrations and detector noise. The angular drift of the HeNe laser is shown to be an unlikely cause of the remaining effects. Further investigations of these are suggested. The interferometer design is recommended for further testing using active stabilization.