Attosecond pulses measured from the attosecond lighthouse
High harmonic generation is the creation of a train of coherent, attosecond bursts. We can control the direction of these bursts through the wavefront of the driving field. Here, we use a technique called the attosecond lighthouse, where we impose a spatial chirp at the focus of the driving field causing its wavefront to rapidly rotate while generating the attosecond pulses; each pulse is uniquely directed in the far field and becomes isolated. We generate attosecond pulses by two different driving sources: a 1 kHz Ti:Sapphire centered at 760 nm, and the idler of a 100 Hz optical parametric amplifier (OPA) centered at 1.8mm. For the higher flux attosecond pulse generated by the 1 kHz source, we can use photoelectron streaking to measure the pulse duration at a second interaction region. We also fully characterize an attosecond pulse at the time of generation using an in-situ measurement, useful for the lower repetition rate and lower flux provided by the 1.8mm source.
