02 WRQ 001 Melles Griot Multiple-Order Quartz Retardation Plate

The Melles Griot 02 WRQ Series Quartz Retardation Plates are recommended for high- and low-power laser applications.

Multiple-order quartz retarders are made from a single crystalline plate. Retardation is slightly temperature dependent. The temperature coefficient of retardance (phase difference between O and E rays at emergence) is approximately 1.0 nm/°C, as deviated from 20°C. Retardance decreases as temperature increases.

First-order retarders, also called zero-order retarders, are assembled from pairs of optically contacted crystalline quartz plates. The quartz plates have orthogonal optic axis directions; therefore, the roles of the ordinary and extraordinary rays are interchanged in passing from one plate to the other. Net retardation is essentially temperature invariant since both plates are nearly equal in thickness (<0.01 nm/°C).

Due to the high degree of accuracy in the manufacturing of these quartz retardation plates, they should not be used far outside of their design wavelength. However, they can be used at wavelengths that are close to their design wavelength, depending on which type they are. Multiple-order plates are more susceptible to changes in wavelength and they should not be used more than several nanometers outside of their design wavelength, unless some degree of change in the retardation amount is tolerable. First-order waveplates, which are much less susceptible to wavelength changes, can be used up to ~2% above or below the design wavelength with little effect on the retardation.