In: Physics

# Consider a two level system interacting with a radiation field. Write down the differential equations defining...

Consider a two level system interacting with a radiation field. Write down the differential equations defining the Einstein A and B coefficients. Define all terms in your equations.

a. Solve for the time varying upper state population density for the case of no external radiation present.

b. In steady state, solve for the photon energy density.

c. What other concept is required to predict the possibility of laser action?

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