Source: B.Halle

The Berek Compensator: A Versatile Tool for Tunable Phase Retardation

Overview of Berek Compensator

A Berek compensator, named after German physicist Max Berek, is a type of tunable phase retardation plate. Also known as a Berek waveplate or Berek tunable retarder, it is made of a single uniaxial birefringent crystal with its extraordinary optical axis perpendicular to the parallel faces. By tilting the plate against the beam, variable retardance can be achieved, with the amount of retardation being proportional to the square of the tilt angle.

Functionality of Berek Compensator

The Berek compensator acts as a tunable true zero-order waveplate, offering advantages over other types of compensators. The tilt angle can be controlled using a rotating dial or similar mechanisms, allowing for precise adjustment. The device is designed to provide tunable phase retardation across different wavelengths, although some wavelength dependence may exist.

Applications of Berek Compensators

Berek compensators find applications in situations requiring tunable phase retardance and zero-order performance, particularly in polarized light microscopy and optical component measurements. They are favored for their versatility in a wide wavelength range and can serve as cost-effective alternatives to other compensators under certain conditions.

Optimizing Performance

To minimize variable beam offset caused by tilting the Berek plate, materials with high birefringence and small thickness are preferred. Anti-reflection coatings on polished surfaces help reduce reflection losses, enhancing overall performance.

Conclusion

In conclusion, the Berek compensator is a valuable tool in optics and photonics, offering tunable phase retardation with zero-order performance. Its versatility and cost-effectiveness make it a popular choice for various applications requiring precise control over phase retardance.

Source: SPW Industrial
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