Question 2 b) of the attatched PDFIn a laser cooling experiment the transition 5

Question 2 b) of the attatched PDFIn a laser cooling experiment the transition 52S1/2 : F = 2 to 52P3/2; F = 3 isexcited by light that has frequency detuning delta = Gamma / 2.Selection rules dictate that the excited state decays back to the initial state so there is a nearly closed cycle of absorption and spontaneous emission but there is some off-resonant excitation tothe F = 2 hyperne level which can decay to F = 1 and be lost from the cycle.The F = 2 level lies about 45Gamma below the F = 3 level.Estimate the average number of photons scattered by an atom before it falls into the lower hyperfinelevel of the ground state conguration. Assume I = ISAT and that the transitionshave similar strengths.