A simple method for counting the number of trapped ions in an ion trap Academic Article uri icon


  • The number of stored Ca+ ions in an ion trap was measured optically by utilizing the metastable states. All the ions trapped are first pumped into the metastable D states. The ions in the metastable D states are transferred to the ground S state via the P state by exciting a D→P transition Each ion then emits one photon through a subsequent P→S spontaneous emission. Thus, the number of photons is the same as the number of trapped ions initially in the metastable states. When a fraction of all the stored ions are pumped into the metastable states, the method is still applicable if the fraction of the ions is known.

author list (cited authors)

  • Okada, K., Nakamura, T., Ohtani, S., Wada, M., Tanaka, J., Kawakami, H., ... Werth, G.

citation count

  • 1

publication date

  • December 1996