1. Laser transient induced by a pumping step t Ip Case of HeNe :  and  c same order of magnitude n0n0 Laser intensity  n th nn

2. Laser transient induced by a pumping step t Ip Case of Nd:YAG:  >>  c spiking  =230µs  c =22ns n0n0 Laser intensity  n th nn

3. Zoom on the first spike

4. Laser transient induced by a pumping step t Ip Case of Nd:YAG:  >>  c spiking  =230µs  c =33ns relaxation oscillations n0n0 Laser intensity  n th nn

5.  n always in steady state 1/R 1 R 2 R 3 n0n0 Laser intensity  n th nn In case of HeNe, approximation correct Comparison with hypothesis chapter 3

6.  n always in steady state 1/R 1 R 2 R 3 In case of Nd:YAG, approximation not correct Comparison with hypothesis chapter 3

7. Q-switched regime E1E1 E2E2 Lower level Upper level E0E0 Fundamental level Amplifying medium Pumping Spontaneous emission Switch off Energy storage in the upper level Cavity blocked : high losses, no laser action

8. E1E1 E2E2 Lower level Upper level E0E0 Fundamental level Amplifying medium Pumping Switch on Q-switched regime Energy storage in the upper level Laser pulse

9. Q-switched regime E1E1 E2E2 Lower level Upper level E0E0 Fundamental level Amplifying medium Pumping Switch on Energy storage in the upper level Cavity draining

10. Q-switched regime and spiking