Photoassociative ionization: a prototype to study collisions between ultracold sodium atoms

Author(s)

Luis Gustavo Marcassa

• Document type: Doctoral Thesis
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Instituto de Física de São Carlos (IFSC/BT)
• Defense date: 1995-05-04

Examining board members

Vanderlei Salvador Bagnato; Marco Aurélio Pinheiro Lima; Luiz Eugenio Machado; Horacio Carlos Panepucci; John Weiner

• Advisor: Vanderlei Salvador Bagnato

Abstract

This works reports on the photo-associative ionization process in ultracold sodium atoms confined in a magneto optical trap. The behavior of the rate constant Kpai is measured as a function of the trapping beams intensity, and as a function of the frequency of a second laser. This study showed that photo-associative ionization occurs in a multi-step process and also showed the importance of spontaneous emission in ultracold collisions. We experimentally confirmed for the first time the Optical Shielding process which prevents atoms from approaching due to repulsive states induced by the interaction of the atoms with the incident light. The understanding of this process is relevant if one intends to increase the number and density of trapped atomic samples. (AU)