Control of atomic ionization using interfering polaritonic pathways

Tunable-dressing-field attosecond transient absorption spectroscopy, which employs XUV attosecond pulse trains and strong-field tunable infrared (IR) pulses, is ideal for studying and manipulating autoionization dynamics in atomic systems. The frequency tunability of the dressing field provides control over different IR-driven couplings of the 3s^-14p bright autoionizing state in argon and the neighboring dark states. Near resonance, the degeneracy between different light-induced states and the bright state leads to the formation of autoionizing polaritons (AIPs). We present a comprehensive study on the role of different IR parameters, in particular the field strength, over AIP dynamics in the continuum. Our experimental measurements are compared with theoretical essential-state simulations, showing exceptional agreement. These results provide new avenues for quantum optical control of AIPs in multi-electronic systems.