Our multiple-order wave plates are crystal quartz optics designed to differentially retard the phase of a polarized beam. With the proper phase shift, the half waveplate can rotate the direction of polarization. For half waveplates, the amount of polarization rotation is twice the amount of waveplate rotation. We offer dual wavelength multiple-order wave plates in addition to our standard single wavelength versions.

A wave plate of practical thickness produces a multiple of λ/4 or λ/2 retardation (e.g., 15 1/2 λ for a ~1mm thick optic). Such a plate will behave as expected at the design wavelength. However, as the optical wavelength is changed, the retardation will change much more rapidly than it would for a true zero-order wave plate. The higher the multiple (or order), the higher the retardance error a multiple-order waveplate will exhibit as the wavelength changes. For more information, please see our Introduction to Waveplates tutorial.

Wave plates are sensitive to temperature changes. A typical multiple-order wave plate has a temperature coefficient of 0.0015λ/°C, compared to 0.0001λ/°C for a zero-order wave plate, so tighter temperature control will be required.

Quartz is an example of a uniaxial crystal, or crystal in which one axis has a different refractive index than the other two axes. The index associated with the unique axis is called the extraordinary index, the ordinary refractive index is associated with the remaining two axes. A half or quarter wave plate is a polished slice of a uniaxial crystal, in which the extraordinary axis lies within the plane of the optic. Light with polarization vector components oriented along the ordinary axis will undergo a phase delay relative to the perpendicular component oriented along the extraordinary axis. Change in polarization state will depend on the input state, and the physical orientation of the waveplate.