P14-1 In a laser rod with the length 120 mm the intensity is increased for a single passage with a factor of 1.4. We assume in this case that we can neglect saturation effects. a) Calculate the gain coefficient. b) What is the small-signal gain of a 230 mm long rod? c) How many round trips are necessary to build up a total energy of one J from one single photon if the wavelength is 500 nm? d) What time will it take?