Absolute absorption cross sections from photon recoil in a matter-wave interferometer

Understand

We measure the absolute absorption cross section of molecules using a matter-wave interferometer.

• A nanostructured density distribution is imprinted onto a dilute molecular beam through quantum interference.
• As the beam crosses the light field of a probe laser some molecules will absorb a single photon.
• These absorption events impart a momentum recoil which shifts the position of the molecule relative to the unperturbed beam.