2 Let's consider atoms with three energy levels 0, 1, and 2. A system of such atoms is pumped with an outside energy sou

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2 Let S Consider Atoms With Three Energy Levels 0 1 And 2 A System Of Such Atoms Is Pumped With An Outside Energy Sou 1 (126.6 KiB) Viewed 53 times

2 Let's consider atoms with three energy levels 0, 1, and 2. A system of such atoms is pumped with an outside energy source (e.g. electric current, flashlight or another laser) that lifts atoms from energy level 0 to level 2 with a rate P2. The atoms relax from level 2 via level 1 to the ground state. The transition rates are governed by the respective lifetimes T2 and T. Assume, that the population at level 0 is so large that pumping does not affect it. an an a) Write down the rate equations and for states 1 and 2. Ot at b) Give the expressions for populations N, and N, as functions of time. Hint: the system of equations can be solved with trial functions N; (t)= a(t).exp(-t/t;). Assume that initially |(when the pump is ignited) all the atoms are at the ground state. \c) Calculate N, and N, at the steady state using constant values of t; = 1 us, T2 = 2 us and P2 = = 1020 cm 's-1