Characteristics and Technical Features

High Isolation

The properties of the LINOS Faraday isolator are determined by the quality of the optical elements and the uniformity of the magnetic field. The entrance and exit polarizers exhibit a very high extinction ratio, so that the isolation is mainly limited by inhomogenities in the crystal material. Specially selected crystal materials with a high Verdet constant combined with permanent magnets with a high remanence enable us to use shorter crystals and obtain an isolation
> 30 dB.

The radiation blocked by the entrance and exit polarizers is not absorbed internally, but is defl ected by 90° with respect to the beam direction. This ensures a stable thermal operation even at higher laser power levels. The blocked radiation can be used for other applications. All optical surfaces are slightly tilted relative to the beam axis.

Low Insertion Loss

The high transmission, typically > 90%, is achieved by using absorption and antireflective coatings with low residual reflectivity on all entrance and exit surfaces.

Large Aperture, Compact Design

All optical elements have been aligned to eliminate beam shading and allow for easy adjustment. Focusing is not necessary.
The compact design is achieved by using rare earth magnets with the highest remanent magnetism and TGG crystal material with a high Verdet constant. The isolator is suitable for divergent beams or in setups with limited space. A minimal optical path length in the isolator results in the lowest possible influence on the image.

Three sides of the entrance and exit polarizers are usable and readily accessible for easy cleaning. The degree of isolation can be adjusted in a wide range.

Mounting Flexibility

The LINOS Faraday isolators can be mounted directly via threaded holes in the housing or via additional base plates or angle brackets.

Applications

The ongoing development and refi nement of laser technology have created a need for optical components that shield the laser resonator from back refl ections. LINOS Faraday isolators provide an efficient method of suppressing instabilities and intensity fluctuations in laser devices.

Typical applications are:

• Protection of the resonator in solid state and gas lasers from back refl ections
• Prevention of parasitic oscillation in multistage solid state amplifiers
• Protection of diode lasers against back scatter and extraneous light