I've been reading up on lasers recently and learnt that within the cavity while the laser light is amplified by the gain coefficient, it loses power due to transmission and absorption. Suppose the pumping radiation comes from a monochromatic source whose energy is not exactly equal to the energy difference between the two levels. For laser operation below threshold, due to broadening of the levels it would still be possible to stimulate gain? But if it the gain way above threshold, there is no overlap between the pumping radiation and energy difference between the two levels as the peaks become very sharp. Would the gain be 0 then?