Model 5540 variable wave plate mounted in a Model9854 Opti-Claw™ mount on a Model 9955 optical pedestal. The performance of a Soleil-Babinet compensator at a much lower cost
Variable zero-order retardance
Ideal for removing arbitrary ellipticity in your experiment
Our Model 5540 Berek’s Variable Waveplate modifies the polarization of collimated beams from any state to any other state with the flexibility, convenience, and precision previously found only in bulky and expensive Soleil-Babinet compensators. True zero-order retardance, minimal wavefront distortion, and beam displacement of less than 150 µm are all featured at an economical price.
The device, based on the polarization compensator first discussed by Berek in 1913†, consists of a plate of uniaxial crystalline material with faces that are perpendicular to the optic axis. At normal incidence, the device is isotropic and introduces zero-phase retardance. The birefringence is varied with a rotation ring that tilts the plate. The orientation of the fast axis associated with this birefringence is adjustable with a second rotation stage. The two independent rotation scales, together with the provided curves, let you set the retardance from 0 to π for all wavelengths from 200 to 1600 nm.
The Berek’s variable waveplate can be directly mounted to an Optical Post or Pedestal Riser, but we recommend using it with our 9854 Opti-Claw adjustable 2 inch (50.8 mm) mount. This allows you to align the waveplate so that it is truly normal to the incident beam, ensuring zero phase retardance and the accuracy of the wave plate.
Model 5540 variable wave plate mounted in a Model9854 Opti-Claw™ mount on a Model 9955 optical pedestal.
You can use the Berek’s variable waveplate as a quarter-wave plate, a half-wave plate, or any arbitrary waveplate at any wavelength between 200 and 1600 nm.
By using the Model 5540 as a half-waveplate, you can rotate the plane of polarization of a linearly polarized laser beam. Follow the waveplate with a linear polarizer to make a variable attenuator.
If you use the Model 5540 as a quarter-waveplate, you can circularly polarize a linearly polarized laser beam. Add a linear polarizer before the wave plate to build a simple and inexpensive isolator.
You can also use the Berek’s waveplate to compensate precisely for small phase shifts produced by other optics in your experiment. Vary the retardance and orientation of the waveplate to produce very small retardances until your system is optimized.