3B Scientific Laser Optics Supplemental Set - Manual (Page 18)

18
E1 Reflraction on planar mirror
(U17300/U17301)
The law of reflection is demonstrated. When a light
ray impinges a plane mirror under an angle
α
it is re-
flected under the same angle ß
α
= ß
Both angles are measured from the perpendicular line
to the mirror plane.
E2 Reflection on two planar mirrors
(U17301)
An interesting relation can be shown:
δ
= 2
γ
where
δ
is the angle between the incident and the
reflected ray and
γ
is the angle between the mirrors'
planes.
E3a Reflection of light rays on concave mirror –
rays are parallel to optical axis
(U17300)
The focal length f of the concave mirror is determined
by the length of the line VF. The curvature radius can
be obtained using the known formula:
f
r
=
2
The distance of the centre of curvature S is twice as
long as the distance of the focus F.
E3b Reflection of light rays on concave mirror –
rays are non-parallel to optical axis
(U17300)
The axis
ϕ
which is perpendicular to the optical axis
and passes through the focus is referred as the focal
plane of the concave mirror. If the parallel rays im-
pinge the mirror, they meet at one point of the axis
ϕ
after the reflection. In the case of the rays parallel to
the optical axis, the point belongs to the axis and is
called the focus (F).