Page 284 - High Power Laser Handbook

252 So l i d - S t at e La s e r s Thin-Disc Lasers 253

25

20

Laser power (kW) 15

10

5 1 disk
2 disks
4 disks
0
0 5 10 15 20 25 30 35 40 45
Pump power (kW)

Figure 10.21 Output power with one, two, and four discs, beam quality M² ≈ 24.
(Courtesy of Trumpf Lase)

30 nm. Simultaneously, the losses due to absorption in the not-pumped
region are negligible, and higher modes are effectively suppressed by
the absorption in the not-pumped region (“gain aperture”).
Figure 10.22 shows the result of a disc operated with more
than 500 W laser power and an M² of better than 1.6. The optical
efficiency of this laser was higher than 35 percent. Even higher

50
500 45
40
400 35
Output power (W) 300 30 Optical efficiency (%)

25
20
200

10
100 15
5
0 0
0 200 400 600 800 1000 1200 1400
Pump power (W)
Figure 10.22 Output power and optical efficiency for operation close to
fundamental mode operation, M² ≈ 1.6.