Basic Knowledge of WavePlates

A waveplate is a device that changes the polarization state of light by changing the phase difference of the incident light. According to the structure, the waveplate is divided into multi-level waveplate, glued zero-order waveplate or compound waveplate and true zero-order waveplate.
True zero-order waveplate, low wavelength sensitivity of retardation, high temperature stability, and large effective angle of acceptance.
Multi-order waveplates are relatively easy to manufacture, but their disadvantages are that they are sensitive to wavelength, temperature, and incident angle.
Gluing a zero-order waveplate is to glue two multi-order waveplates together. The full-wave optical path difference is eliminated by aligning the fast axis of one waveplate with the slow axis of the other waveplate, leaving only the desired optical path difference.
The glued waveplate can improve the influence of temperature on the waveplate to a certain extent, but it also increases the sensitivity of the retardation of the waveplate to the incident angle and wavelength.
The waveplate is divided into materials, and there are various crystal waveplates and polymer waveplates. Commonly used crystals include mica, calcite, quartz, etc.
Due to its relatively small birefringence coefficient, polymer materials are suitable for manufacturing true zero-order waveplates, especially in the visible waveband and large-aperture waveplates.
In addition, there are achromatic waveplates, which are laminated with precise alignment of several layers of different polymers or crystals. The main advantage of the achromatic waveplate is that the retardation is not sensitive to the change of the wavelength within a certain bandwidth.
The waveplate is divided according to the amount of delay, there are 1/4 waveplate, 1/2 waveplate and full waveplate.