  It has been almost one hundred years since Einstein formulated his special
theory of relativity in 1905. He showed that the basic space-time symmetry is
dictated by the Lorentz group. It is shown that this group of Lorentz
transformations is not only applicable to special relativity, but also
constitutes the scientific language for optical sciences. It is noted that
coherent and squeezed states of light are representations of the Lorentz group.
The Lorentz group is also the basic underlying language for classical ray
optics, including polarization optics, interferometers, the Poincare\'e sphere,
one-lens optics, multi-lens optics, laser cavities, as well multilayer optics.
