We consider Sodium atoms with nuclear spin I=3/2. 1) Draw approximately an energy level diagram of...

 

Transcribed Image Text:

We consider Sodium atoms with nuclear spin I=3/2. 1) Draw approximately an energy level diagram of the hyperfine structure of the 3s 2S1/2 and 3p ²P3/2 levels and indicate the allowed electric dipole transitions between the two levels. 2) In a laser cooling experiment, the transition 3s ²S12, F-2, to 3p ²P3/2, F-3 is excited by light that has a frequency detuning of = -0/2= -5 MHz (to the red of the transition). Selection rules dictate that the excited state decays back to the initial state so that there is a nearly closed cycle of absorption and spontaneous emission. However, there is some off-resonant excitation to the F-2 state which can decay to the F-1 state and be "lost" from the cycle. The F-2 level lies 60 MHz below the F-3 level. Estimate the average number of photons scattered by an atom before it falls into the lower hyperfine level of the ground configuration. (Assume that the transitions have similar strengths and that I<<Isat). Hint: Compare the scattering rates for F=2→F'-2 and F=2→F'=3 states. Assume that the spontaneous decay rates from F'=2 to F-2 and F=1 are the same. 3) To counteract the leakage out of the laser cooling cycle, experiments use an additional laser beam that excite atoms out of the F=1 level (so that they come back to F-2). Suggest a suitable transition for this repumping process. We consider Sodium atoms with nuclear spin I=3/2. 1) Draw approximately an energy level diagram of the hyperfine structure of the 3s 2S1/2 and 3p ²P3/2 levels and indicate the allowed electric dipole transitions between the two levels. 2) In a laser cooling experiment, the transition 3s ²S12, F-2, to 3p ²P3/2, F-3 is excited by light that has a frequency detuning of = -0/2= -5 MHz (to the red of the transition). Selection rules dictate that the excited state decays back to the initial state so that there is a nearly closed cycle of absorption and spontaneous emission. However, there is some off-resonant excitation to the F-2 state which can decay to the F-1 state and be "lost" from the cycle. The F-2 level lies 60 MHz below the F-3 level. Estimate the average number of photons scattered by an atom before it falls into the lower hyperfine level of the ground configuration. (Assume that the transitions have similar strengths and that I<<Isat). Hint: Compare the scattering rates for F=2→F'-2 and F=2→F'=3 states. Assume that the spontaneous decay rates from F'=2 to F-2 and F=1 are the same. 3) To counteract the leakage out of the laser cooling cycle, experiments use an additional laser beam that excite atoms out of the F=1 level (so that they come back to F-2). Suggest a suitable transition for this repumping process.

Answer rating: 100% (QA)

Answer 1 2 3 Ano 1 Gover Nieclear Jhain I 29312 The tra... View the full answer