Elimination of degenerate trajectory of single atom strongly coupled to the tilted cavity TEM10 mode

TL;DR

This paper demonstrates precise measurement and elimination of degenerate trajectories of single atoms strongly coupled to a tilted high-order cavity mode, enabling high-resolution tracking and velocity measurement of atoms falling freely.

Contribution

The study introduces a novel method using a tilted TEM10 cavity mode to uniquely determine single atom trajectories, overcoming degeneracy issues in atom tracking.

Findings

Achieved high-precision atom position measurement of 0.1 μm.

Obtained spatial resolution of 5.6 μm in 10 μs.

Measured atom velocity and temperature in the magneto-optic trap.

Abstract

We demonstrate the trajectory measurement of the single neutral atoms deterministically using a high-finesse optical micro-cavity. Single atom strongly couples to the high-order transverse vacuum TEM_{10} mode, instead of the usual TEM_{00} mode, and the parameter of the system is (g_{10},\kappa ,\gamma )=2\pi \times (20.5,2.6,2.6)MHz. The atoms simply fall down freely from the magneto-optic trap into the cavity modes and the trajectories of the single atoms are linear. The transmission spectrums of atoms passing through the TEM10 mode are detected by a single photon counting modules and well fitted. Thanks to the tilted cavity transverse TEM10 mode, which is inclined to the vertical direction about 45 degrees and it helps us, for the first time, to eliminate the degenerate trajectory of the single atom falling through the cavity and get the unique atom trajectory. Atom position with high precision of 0.1{\mu}m in the off-axis direction (axis y) is obtained, and the spatial resolution of 5.6{\mu}m is achieved in time of 10{\mu}s along the vertical direction (axis x). The average velocity of the atoms is also measured from the atom transits, which determines the temperature of the atoms in magneto-optic trap, 186{\mu}K {\pm} 19{\mu}K.