Optics Introduction
For thousands of years, people have been intrigued by the behavior and properties
of light. Archeologists have unearthed mirrors from ancient Egypt (c. 1900
B.C.), and there are written references to Israelite “looking glasses” from
1200 B.C. and to Greco-Roman “burning glasses” in use 1500 years ago. While the philosophers of those eras were
able to propose theories about the nature of light, the scientific study of
light began in the seventeenth century with the work of Galileo, Snell, Fermat and
Newton. Their
theories of geometrical optics, as well as the instruments they devised, formed
the foundation of classical optics.
Light
is a form of electromagnetic radiation that propagates as a transverse wave. In
geometrical optics the wavelength of the light is assumed to be much smaller than
the physical dimensions (lengths and component sizes) of the system involved.
As a result, rays, rather than wavefronts, are used to model the propagation of
the light. A ray is an idealized pencil of light that travels a straight line
within a homogeneous medium. Analyzing the performance of an optical system is
a matter of methodically tracing representative rays. This technical information
is a basic introduction to geometrical optics analysis. For more detailed
information about specific optical components, systems and coatings, please
refer to the additional sections of Tech Info.