(a) A dye molecule has emission cross section 4 10 -16 cm2 at = 550 nm, and flu- orescence lifetime 3 ns. Assuming the transition is homogeneously broadened, cal- culate the signal intensity at which the gain is reduced by a factor of two. (b) The Nd:glass transition has peak emission cross section 4 10 -20 cm2 at = 1054 nm, and fluorescence lifetime 290 s. If the transition is homogeneously broadened, de- termine the signal intensity at which the Nd:glass gain is reduced by a factor of two. Repeat if the transition is inhomogeneously broadened