Impact parameter selective Rydberg atom collision by optical tweezers

Abstract

Optical tweezers are used to facilitate cold collisions between two Rydberg rubidium atoms (⁸⁷Rb) by controlling the impact parameter and collision energy. One atom is held stationary while the other is propelled to a constant velocity. After the tweezers are deactivated, both atoms are excited to a Rydberg state using a π-pulse. Following the collision, a second π-pulse is applied. If the stationary atom undergoes minimal momentum transfer and returns to its ground state, it can be recaptured when the tweezer is reactivated. The collision probability as a function of the impact parameter is extracted from the atom loss in the tweezer and used to determine the collisional cross section between Rydberg atoms. Numerical simulations of elastic two-body collisions agree well with the experimental data, providing valuable insights into the parameter regime where quantum effects will become important.