Measuring the branching ratios from they8P9/2state to metastable states in eu

Abstract

We measure the branching ratios from the y 8 P 9/2 excited state to six metastable states of europium through fluorescence spectroscopy of an atomic beam. The sum of the six branching ratios is estimated to be 1.05(2) × 10 −3 . This research provides us with insightful information to determine the feasibility of using the a 8 S 7/2 − y 8 P 9/2 transition in order to implement the Zeeman slowing for europium atoms in the ground state. Based on this result, we also propose a scheme for Zeeman slowing and magneto-optical trapping, using a specific metastable state which has a cyclic transition.

Narrow-line magneto-optical trap for europium

“…By driving the 460 nm transition, atoms are pumped from the ground state into two intermediate states a 10 D • 9/2 and a 10 D • 11/2 ; then, they are pumped to a 10 D • 13/2 by driving the 507 nm and 513 nm transitions, respectively. The total transfer efficiency is estimated as up to 19 % [19,22]. The atoms in a 10 D • 13/2 are then Zeeman slowed and captured in a MOT (yellow-MOT) using the a 10 D • 13/2 ↔ z 10 F 15/2 cooling transition at 583 nm with a natural linewidth of Γ 583 /2π = 8.2 MHz [22].…”

“…The atoms in a 10 D • 13/2 are then Zeeman slowed and captured in a MOT (yellow-MOT) using the a 10 D • 13/2 ↔ z 10 F 15/2 cooling transition at 583 nm with a natural linewidth of Γ 583 /2π = 8.2 MHz [22]. The captured metastable atoms are successively pumped back to the ground state with the pumping-back efficiency of 94 % [19,22] by driving two transitions at the wavelengths of 609 nm and 1204 nm. Pumped back atoms are cooled and trapped in the narrow-line MOT (red-MOT) using the a 8 S • 7/2 ↔ z 10 P 9/2 cooling transition at 687 nm with a natural linewidth of Γ 687 /2π = 97 kHz [21].…”

“…Cold atoms in the MOT were loaded to an optical dipole trap, and quantum degenerate gases were obtained through successive evaporative cooling [5,6,18]. However, this approach cannot be directly applied for Eu atoms because the optical transition broad enough for Zeeman slowing has large optical leaks; excited atoms decay to at least six metastable states with a total probability of 1.05(2) × 10 −3 [19]. Hence, we pumped atoms to another metastable state that exhibits a quasicyclic transition at 583 nm and implemented the Zeeman slowing and MOT [20].…”

Magneto-optical trapping of optically pumped metastable europium

“…However, eleven low-lying odd-parity states exist for |e1 . The lower limit to the probability of leakage of the |g ↔ |e1 system was spectroscopically determined to be 1.05(2) × 10 −3 [29]. This suggests a pessimistic outlook for laser-cooling using this transition; we cannot expect to laser-cool the atoms without using multiple repumping lasers operating at different wavelengths to plug the leaks.…”