United photonics Technology Zero Order Waveplate-Optically Contacted Optically Contacted zero order waveplate is constructed by two quartz plates with their fast axis crossed, the two plates are constructed by optically contacted method, the optical path is epoxy free. The difference in thickness between the two plates determines the retardation. Zero order waveplates offer a substantially lower dependence on temperature and wavelength change than multi order waveplates. Optically Contacted Thickness 1.5~2mm Double Retardation Plates Broad Spectral Bandwidth Wide Temperature bandwidth Hight Damage Threshold Specifications: Material:Quartz Diameter Tolerance:+0.0, -0.1mm Wavefront Distortion :8 @ 632.8nm Retardation Tolerance:300 Parallelism:90% Coating:S1&S2: R