
444 OPTICS FOR ENGINEERS
E
1
E
1
E
2
(A)
E
1
E
2
(B)
E
1
E
2
(C)
Figure 14.2 Some second-order processes. Probably the most common second-order process
is second-harmonic generation (A). Raman scattering is a first-order process, but stimulated
Raman scattering (B and C) is second-order.
“laser” light can now be produced at levels sufcient for a good laser pointer using a small bat-
tery as a power source. Starting with high-power laser diodes, it is possible to produce several
watts of this light. Many other wavelengths can be generated as second and higher harmonics
of other lasers.
Second harmonic generation also occurs in natural materials, including biological ...