Figure 2-4.—Light ray striking a glass surface.
However, curved specular surfaces may change the
divergence.
The amount that the divergence is
changed depends on the curvature of the surface and
the size of the beam striking the surface. Figure 2-5
illustrates these two surfaces and how they will reflect
a laser beam striking them. (Note: The divergence
and curvature of the reflector have been exaggerated
to better illustrate the effect.)
Diffuse Reflection
A diffuse surface will reflect the striking laser
beam in all directions.
maintained when a laser
reflector.
Whether a surface acts
The beam path is not
beam strikes a diffuse
as a diffuse or specular
reflector depends on the wavelength of the striking
laser beam.
A surface that would be a diffuse
reflector for a visible laser beam might be a specular
reflector for an infrared laser beam.
As opposed to specular reflectors, various
curvatures of diffuse reflectors have little effect on the
reflected beam (figure 2-6).
Figure 2-5.—Specular reflection.
Figure 2-6.—Diffuse reflections.
2-3
