Rami Arieli: " The
Laser Adventure" Chapter 1.2.3 page 3
Example 1.3:
Can waves with different wavelength
be coherent?
Solution to example 1.3:
Waves with different wavelengths can have the same phase in one point
in space (or even in some points), but they can not keep this phase difference
as can be seen in figure 1.10.
Figure 1-10: Waves with different wavelengths
As can be seen from this example, coherence
depends on monochromaticity. Coherence is important for applications
like interference and diffraction,
and the entire process of holography
is based upon it, as explained in
chapter 10.