The coherent control of light with matter, enabling storage and manipulation
of optical signals, was revolutionized by electromagnetically induced
transparency (EIT), which is a quantum interference effect. For strong
electromagnetic fields that induce a wide transparency band, this quantum
interference vanishes, giving rise to the well-known phenomenon of
Autler-Townes splitting (ATS). To date, it is an open question whether ATS can
be directly leveraged for coherent control as more than just a case of "bad"
EIT. Here, we establish a protocol showing that dynamically controlled
absorption of light in the ATS regime mediates coherent storage and
manipulation that is inherently suitable for efficient broadband quantum memory
and processing devices. We experimentally demonstrate this protocol by storing
and manipulating nanoseconds-long optical pulses through a collective spin
state of laser-cooled Rb atoms for up to a microsecond. Furthermore, we show
that our approach substantially relaxes the technical requirements intrinsic to
established memory schemes, rendering it suitable for broad range of platforms
with applications to quantum information processing, high-precision
spectroscopy, and metrology.Comment: 14 pages with 6 figures; 3 pages supplementary info with 2
supplementary figure
