Rabi-cycle laser cooling of atoms using long lived transition

1994 Fiscal Year Final Research Report Summary

• Project/Area Number: 05555017
• Research Category: Grant-in-Aid for Developmental Scientific Research (B)
• Allocation Type: Single-year Grants
• Research Field: Applied optics/Quantum optical engineering
• Research Institution: Science University of Tokyo
• Principal Investigator: MORINAGA Atsuo Science Univ. of Tokyo Faculty of Sci.& Tech. Assoc.Professor, 理工学部, 助教授 (90246687)
• Co-Investigator(Kenkyū-buntansha): YAMASHITA Masahumi Science Univ. of Tokyo Faculty of Sci.& Tech. Lecturer, 理工学部, 講師 (80089383) ; TAKO Toshiharu Science Univ. of Tokyo Faculty of Sci.& Tech. Professor, 理工学部, 教授 (20016794)
• Project Period (FY): 1993 – 1994
• Keywords: laser cooling / Rabi-cycle / long lived transition

Research Abstract

Rabi-cycle laser cooling is one of the promising way to get cold atoms, since cooling time does not depend on the natural lifetime of the spontaneous emission but depends on the Rabi-cycle. The concept of Rabi-cycle cooling with pi pulses was presented. We examined the feasibility of the Rabi-cycle cooling by simulation. The recommended conditions are as follows.
1)Frequencies of absorption and stimulated emission for cooling are symmetrical respect to the resonance frequency depending on Doppler effect.
2)Number of cycles which are responsible to the effective cooling depends on the precision of pi pulse
3)laser frequency must be shifted to the resonance by the recoil frequency per each pulse.
4)A speed of frequency charping must be coincide with that of deceleration.
On the basis of simulation, we desined a prototype for the Rabi-cycle laser cooling of Ca atom using a long lived transition of ^1S_0-^3P_1. We have already formed the pi pulse chain using an electro-optic modulator drived by a frequency of 1 MHz and introduced the pi pulse chain to Ca atomic beam. At present we are making a timing circuit which charps the laser frequency matching to the speed of deceleration.