Holographic Storage of Ultrafast Photonic Qubit in Molecules

Abstract

Herein, it is demonstrated that ultrashort spatially structured beams can sculpt a sample of gas-phase molecules like a 4D material to produce a spatial pattern of aligned molecules whose shape and temporal evolution allow to restore the spatial light information on a time-delayed reading pulse. To do so, the spatial phase and amplitude information of ultrashort light beams are encoded into rotational coherences of molecules by exploiting the interplay between spin angular momentum and orbital angular momentum. The field-free molecular alignment resulting from the interaction leads to an inhomogeneous spatial structuring of the sample allowing to transfer the encoded information into a time-delayed probe beam. The demonstration is conducted in ${\text{CO}}_2$ molecules. Besides applications in terms of THz bandwidth buffer memory, the strategy features interesting prospects for establishing versatile optical processing of orbital angular momentum (OAM) fields, for studying various molecular processes, or for designing new photonic devices enabling to impart superpositions of OAM modes to light beams.