Fig. 4: An application of multi-photon induced continuum structure.
a The level scheme of Si:Bi with a hyperfine split ground state and the 3p± excited state. The MPICS ionization window is located at a detuning Δ = 0.4 meV above resonance. b Small-signal absorption spectrum against photon energy ħω of Si:Bi illustrating the well-resolved hyperfine splitting (data from ref. 50). c The MPICS windows for a field amplitude in atomic units of F/Fa = 0.15 (solid line) and 0.1 (dash line) illustrating the available state-selective ionization contrast.
