Optronics — Introduction

Curiously, the termoptronics brings together two historically very different scientific names:

• one refers to optics, a science whose origins date back several centuries – or even several millennia – since the Babylonians and Egyptians, then the Greeks and Romans, had already formulated the first laws of reflection and carried out the first demonstrations of focusing;

• the other refers to electronics, which is unquestionably a creation of the 20th century.

As we shall see later, the recent combination of these two technical fields has been, and will continue to be for a long time to come, a source of new concepts and equipment for both the military and civilian sectors.

Often, in such cases, spectacular events are needed to reveal to the public the capabilities and very existence of such technical or scientific innovations.

The Gulf War, in early 1991, was particularly revealing for non-specialists and the uninitiated. For the first time, the non-specialized press made extensive use of electronic terminology.

Although the term – optronics – was introduced in the early 1970s, there is still sometimes (even in specialist circles) some confusion between the terms:

• optics ;

• electronic optics ;

• optoelectronics ;

• electro-optics (acousto-optics, magneto-optics) ;

• optronics.

To make things clearer, there are a few rules to follow.

• The termoptical is reserved, of course, for components, sub-assemblies and assemblies comprising lenses, mirrors, prisms, etc., and generally contributing to the deflection and/or focusing of photons.

• The term electron optics is reserved for vacuum devices that deflect and/or focus electrons, a technique that is analogous to photon deflection.

• Optoelectronics mainly refers to components that transform :

  • or incident photons into electrons, as in the case of visible light, ultraviolet or infrared radiation detectors;

  • or from electrons to photons, as is the case in many light sources, particularly light-emitting diodes and laser diodes.

• Electro-optics applies to components whose optical characteristics can be modified by the application of an electrical voltage or current (liquid...