Fig 2.0. This diagram shows the
ordinary polarisation of light, the electro-magnetic waves propagate
Polarised light, is light in
which the oscillations of the electric field oscillate in either
the horizontal or vertical planes (not to be confused with E
and H planes). Light can also be circularly polarised. We will
cover this in the laser tutorials in more detail.
Light can be polarised by the
use of simple polarisation filters. When dealing with Lasers,
more advanced methods are used to polarise light.
Fig 2.1. This Diagram shows the
details of light polarisation. A polarising filter work by subtracting
the components of light orientated in a particular plane; if
a second filter is placed in front of the first, with its transmission
planes crossed ( at right-angles ) with the first filter, then
NO light will be transmitted. A good example of this is in liquid
crystal displays, which operate on the basis of polarised light.
In this section we will only
cover the basics on polarisation. We will cover polarisation
in greater details in the laser tutorials.