The transition from energy level 0 to energy level 3 in a 4-level laser system is optical Provided with pump. Transition rate from energy level 3 to energy level 2 (1/1 nano seconds). Energy level 2 has a lifetime of 250 microseconds.Energy from energy level 0 There is no transition to level 1. The transition ratio from 2 to 0 is 0.4 and the ratio from 2 to 1 is 0.6. The transition from 1 to 0 is 25 nanoseconds. a) Rate eq, ignoring the stimulated emission from 2 to 1 pass Write down (ratio equations). b) 10^19 cm^-3 atoms at Level 2 for the steady state population Calculate the power absorbed per unit volume.