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16 A two-level system has an energy difference of AE= 2.5 eV. Assuming the emission only has natural broadening and the
Posted: Fri Apr 29, 2022 10:50 am
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- 16 A Two Level System Has An Energy Difference Of Ae 2 5 Ev Assuming The Emission Only Has Natural Broadening And The 1 (52.47 KiB) Viewed 45 times
16 A two-level system has an energy difference of AE= 2.5 eV. Assuming the emission only has natural broadening and the frequency width of the emission line is 7.5 x 107 Hz. (i) What is the population ratio Nz/N1 at T = 300 K? At what temperature will the population ratio be doubled from the room temperature? [3] (ii) What is the Einstein coefficient Azi? [2] (ii) An incoming photon causes a stimulated emission of the system. What is the frequency of the incoming photon? [2] (iv) Describe the procedures of spontaneous emission and stimulated emission, respectively, and specify the different properties of light emitted from the two mechanisms. [6] (v) Sketch the diagrams of a 3-level and a 4-level lasing system, respectively. Describe the working principles and explain why a 4-level system is considered to be more effective in achieving population inversion than a 3-level system. [7]