Fig. 1. Energy level structure of Dy³⁺ doped laser with cascaded output

Fig. 2. Schematic diagram of cascade output laser based on Dy∶PGS crystal

Fig. 3. Population density varying with time

Fig. 4. Laser output power varying with time. (a) Idler off; (b) idler on

Fig. 5. Pump power, signal power and idler power varying with position at stable state. (a) Pump power; (b) signal power; (c) idler power

Fig. 6. Influence of pump power on output power

Fig. 7. Influence of crystal length on output power

Fig. 8. Influence of reflectance of output mirror on output characteristics of signal light. (a) Output power; (b) slope efficiency