OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN

**Definition:** This place covers:

This subclass covers the control of light by optical devices or arrangements involving at least one element with at least one optical medium, the optical properties thereof being changeable by the influence of external forces or fields affecting the element.

The following is a non-exhaustive list of the optical properties that can be changed in the optical element:

The following is a non-exhaustive list of the external forces or fields which can affect the optical element:

The following optical elements are therefore covered, the list being not exhaustive:

Non-linear optics, i.e. devices or arrangements in which the electric or magnetic field component of the light beam influences the optical properties of the medium.

Control of light beams by electromagnetic waves, e.g. radio waves, or by electrons or other elementary particles.

Optical analogue/digital converters, i.e. devices performing the digitalisation of an optical analogue signal, insofar these converters are based in substantial manner on elements which are provided for under the bullets above.

Demodulating light.

Transferring the modulation of modulated light, i.e. transferring the information from one optical carrier of a first wavelength to a second optical carrier of a second wavelength.

Frequency changing of light, e.g. by quantum counters.

Optical logic elements.

Optical bistable devices, i.e. devices exhibiting two different optical output states for a same optical input value.

**Glossary:** - Control: When referred to light or optical, covers affecting or directing one or more of the following properties of light: intensity; colour; phase; frequency or wavelength; polarisation; direction and one or more of the following optical operations: gating; switching or deflecting; modulation, demodulation or transfer of modulation. - Light: Applies to electromagnetic radiation not only in the portion of the electromagnetic spectrum which can be perceived by the human eye (i.e. visible) but also to ultraviolet or infrared radiation. - Optical, Optics: Applies not only to visible light but also to ultraviolet or infrared radiation.