This type of zero order waveplate is designed for high damage threshold applications (> 1GW/cm2).
It is made of a very thin quartz, with the thickness of 0.038-0.09mm
In fiber-optic communications, single plate true zero order waveplate has seen applications in some devices, especially in the form of rectangle and square instead of circle, 2*2mm or 0.8*1.3mm, for instance, are commonly produced by Photonchina.