The substrates of Zero phase reflectors are usually Silicon or OFHC Copper. In most laser machines, one or several Zero-Phase Reflectors are used to forward the laser beam from the cavity to the working head. At these mirrors, reflectance should be as high as possible in order to minimize loss of laser power. In addition, phase shift between the s- and p-polarized components of the reflected beam should be as low as possible in order to avoid disturbing the polarization of the laser beam.

Specifications
Material	Silicon (Si) Single Crystal
	OFHC Copper
Diameter Tolerances	+.000"  -.005
Thickness Tolerances	±.010"
Flatness	1/40 wavelength @ 10.6 μm
Parallelism	< 3 arc minutes
Surface Quality	< 10/5  scratch ­ dig Laser Finish
Spectral Performance
Phase Shift	<2.0° between p and s polarization for 10.6μm operation only @ 45° Angle Of Incidence
Reflectance	> 99.6% average @ 10.6μm
Absorption	< .18% @ 10.6μm
Coating optimized to maintain low phase shift in beam delivery systems where a 90° phase retarder exists to maintain the circular polarization.

P/N	Substrate	Dia	Edge Thickness	Coating
		(inch)	(inch)
ZPR-0712-0	Si/ Cu	0.750''	0.120''	Zero phase shift
ZPR-1012-0	Si/ Cu	1.000''	0.120''	Zero phase shift
ZPR-1112-0	Si/ Cu	1.100''	0.120''	Zero phase shift
ZPR-4035-0	Si/ Cu	4.000''	0.350''	Zero phase shift
ZPR-38-6-0	Cu	38mm	6mm	Zero phase shift
ZPR-38-8-0	Cu	38mm	8mm	Zero phase shift
ZPR-38-10-0	Cu	38mm	10mm	Zero phase shift
ZPR-1516-0	Si/ Cu	1.500''	0.160''	Zero phase shift
ZPR-1520-0	Si/ Cu	1.500''	0.200''	Zero phase shift
ZPR-1525-0	Si/ Cu	1.500''	0.250''	Zero phase shift
ZPR-1538-0	Si/ Cu	1.500''	0.375''	Zero phase shift
ZPR-1539-0	Cu	1.500''	0.394"	Zero phase shift
ZPR-1579-0-WC	Cu	1.500''	0.787"	Zero phase shift
ZPR-1816-0	Si/ Cu	1.750''	0.160''	Zero phase shift
ZPR-50-5-0	Si/ Cu	50mm	5mm	Zero phase shift
ZPR-2020-0	Si/ Cu	2.000''	0.200''	Zero phase shift
ZPR-50-10-0	Si/ Cu	50mm	10mm	Zero phase shift
ZPR-50-25-0-WC	Cu	50mm	25mm	Zero phase shift
ZPR-2038-0	Si/ Cu	2.000''	0.375''	Zero phase shift
ZPR-57.15-10-0	Si/ Cu	57.15mm	10mm	Zero phase shift
ZPR-60-10-0	Si/ Cu	60mm	10mm	Zero phase shift
ZPR-60-15-0	Si/ Cu	60mm	15mm	Zero phase shift
ZPR-60-25-0-WC	Cu	60mm	25mm	Zero phase shift
ZPR-63.5-10-0	Si/ Cu	63.5mm	10mm	Zero phase shift
ZPR-2525-0	Si/ Cu	2.500''	0.250''	Zero phase shift
ZPR-68-20-0	Si/ Cu	68mm	20mm	Zero phase shift
ZPR-68-34-0-WC	Cu	68mm	34mm	Zero phase shift
ZPR-70-25-0-WC	Cu	70mm	25mm	Zero phase shift
ZPR-75-25-0-WC	Cu	75mm	25mm	Zero phase shift
ZPR-75-15-0	Si/ Cu	75mm	15mm	Zero phase shift
ZPR-76.2-15-0	Cu	76.2mm	15mm	Zero phase shift
ZPR-3025-0	Si/ Cu	3.000''	0.250''	Zero phase shift
ZPR-3050-0	Cu	3.000''	0.500''	Zero phase shift