Attosecond stable dispersion-free delay line for easy ultrafast metrology.

We demonstrate a dispersion-free wavefront splitting attosecond resolved interferometric delay line for easy ultrafast metrology of broadband femtosecond pulses. Using a pair of knife-edge prisms, we symmetrically split and later recombine the two wavefronts with a few tens of attosecond resolution and stability and employ a single-pixel analysis of interference fringes with good contrast using a phone camera without any iris or nonlinear detector. Our all-reflective delay line is theoretically analyzed and experimentally validated by measuring 1st and 2nd order autocorrelations and the SHG-FROG trace of a NIR femtosecond pulse. Our setup is compact, offers attosecond stability with flexibility for independent beam-shaping of the two arms. Furthermore, we suggest that our compact and in-line setup can be employed for attosecond resolved pump-probe experiments of matter with few-cycle pulses.