Page 249 - High Power Laser Handbook

218 So l i d - S t at e La s e r s Nd:YAG Ceramic ThinZag® High-Power Laser Development 219

20

Output power (kW) 10 5
15

0
0.00 0.05 0.10 0.15 0.20 0.25 0.30
Time (s)
Figure 9.14 Short-pulse measurements were made using the TZ-3 module.
Output of 16.8 kW was achieved in 200-ms pulses. The calculated optical
efficiency (laser output/pump diode output) is 25 percent.

60

50

40
Power (kW) 30

20

10

0
0.1 0.2 0.3 0.4 0.5 0.6 0.7
Output coupler feedback (ratio)

Figure 9.15 Model calculations of expected power extraction from three
TZ-3 modules. The red curve predicts CW and the blue curve low duty cycle
(LDC) performance.

highest feedback that can be achieved is about 40 percent; thus, oper-
ating with less than three modules would not allow good extraction.
If the laser medium is not operating with good extraction, other loss
mechanisms (i.e., amplified spontaneous emission [ASE] or parasitic
losses) can further reduce the optical extraction.