Opt⚙City ®-Quality Crystal & Optical Components
Variable waveplate is tunable retarder with a variable (controlled) birefringence or thickness. Variable waveplates can be used to tune a quarter-waveplate or half-waveplate to a specific wavelength of light, shift the retardation value for a single wavelength of light, or as a pure phase modulator for a linear polarized light beam. There are different kinds of variable waveplates.
The Berek tunable waveplate consists of a plate of uniaxial crystalline material with faces that are perpendicular to the optic axis. At normal incidence, the Berek variable waveplate is isotropic and introduces zero phase retardance. The birefringence is varied by tilting the plate. Berek tunable Waveplate is variable true zero order waveplate.
The electrically controllable waveplate (also called active retarder or voltage-controlled waveplate) is a variable waveplate that its phase retardation can be actively controlled by varying the applied voltage. Electro-optic crystal or liquid crystal are used for making such variable waveplate. Pockel Cell and Photoelastic modulator(PEM) are Electrically Controllable Waveplates.
The Soleil-Babinet compensator is a continuously variable, zero-order retarder (waveplate) that operates over a broad wavelength range. The classical design of the compensator consists of a long birefringent wedge and a fixed wedge mounted to a compensator plate. The retardance is adjusted by moving the position of the long wedge relative to the short wedge. This allows the retardation to vary continuously while maintaining a uniform retardance across the aperture at any given setting.
Variable waveplate can be used to compensate precisely for small phase shifts produced by other optics. Vary the retardation and orientation of the waveplate to produce very small retardation until system is optimized. Combined with polarizer or polarizing beamsplitter, variable waveplate can be used for making devices such as Variable Attenuator.
English 中文 Português Deutscheрусскийعربى Españolfrançais日本語