Fig. 2: Experimental setup.
a, The shaded regions highlight different parts of the optical setup: nonlinear fibre stages in pink, IPDFG in blue and EOS in green. b, The spectrum of the laser (red), the first fibre stage (blue) and the second fibre stage black). c, Measured (top) and retrieved (bottom) spectrograms. The near-single-cycle pulses were measured after the nonlinear compression stages via SHG-FROG. d, The retrieved temporal pulse duration at the output of the second fibre at a 1 MHz repetition rate. e, The retrieved spectral intensity and phase. DM, dichroic mirror; WP, wedge pair; BS, beam splitter; WGP, wire grid polarizer; FEL, long-pass filter; FES, short-pass filter; QWP, quarter-wave plate; BD, balanced photodiode; EDFA, erbium-doped fibre amplifier; FS, fiber stage.
