6.2 Generation of short laser pulses by Quality factor (Q) switching. (a) What is the energy Ep and power Pp of a Q-switched laser pulse (hint: use energy balance with An the inversion built up until Q-factor is switched, V volume of optically active material in resonator, tp pulse duration). Estimate maximum Ep and Pp for given number density nion of optically active ions in the amplifier (e.g. Nd:YAG crystal): nion = 109 cm, = 1064 nm, tp 10 ns, V = 1 cm). This laser pulse is focused to a spot of area A = 1 mm. Calculate the laser energy density (fluence) and intensity in the spot. (d) Is pulse duration tp in Q switching independent on photon storage time in resonator Tres. (b) (c)