The output coupler is typically composed of ZnSe in order to minimize absorption and thermal distortion while transmitting a high-power laser beam.

Specifications
Material	CVD Zinc Selenide (ZnSe) Laser Grade
Diameter Tolerances	+.000" , -.005"  for parts up to 2.000" ?
	+.000" , -.010"  for parts from 2.50"  to 6.000" ?
Thickness Tolerances	±.010"
Parallelism	< 3 arc minutes
Surface Quality	< 40/20 scratch – dig Laser Finish
Spectral Performance
Side 1
Partial Reflectance Values as indicated
Tolerances on Reflectance
25-70%      ±2.0%
75-85%      ±2.0%
90-95%      ±1.5%
Side 2
Standard high-efficiency low loss anti-reflectance thin film coating applied to this side only
Reflectance per surface @ 10.6μm for normal incidence <0.20%
Transmission	> 99.2%

P/N	Substrate	Dia	Edge Thickness(mm)	Radius	Coating
				Side1/Side2	Side1/Side2
OC-0512-75	ZnSe	12.7mm	3mm	PO/PO	75%R/AR
OC-0512-9-8.5-70	ZnSe	12.7mm	3mm	9MCC/8.5MCX	70%R/AR
OC-0512-9-8.5-75	ZnSe	12.7mm	3mm	9MCC/8.5MCX	75%R/AR
OC-0512-9-8.5-85	ZnSe	12.7mm	3mm	9MCC/8.5MCX	85%R/AR
OC-0512-12-10-70	ZnSe	12.7mm	3mm	12MCC/10MCX	70%R/AR
OC-0512-12-10-75	ZnSe	12.7mm	3mm	12MCC/10MCX	75%R/AR
OC-0512-12-10-80	ZnSe	12.7mm	3mm	12MCC/10MCX	80%R/AR
OC-0512-12-10-85	ZnSe	12.7mm	3mm	12MCC/10MCX	85%R/AR
OC-0512-92	ZnSe	12.7mm	3mm	PO/PO	92%R/AR
OC-0512-95	ZnSe	12.7mm	3mm	PO/PO	95%R/AR
OC-1024-30-30-65	ZnSe	25.4mm	6mm	30MCC/30MCX	65%R/AR
OC-1024-20-12-65	ZnSe	25.4mm	6mm	20MCC/12MCX	65%R/AR
OC-1024-20-20-30	ZnSe	25.4mm	6mm	20MCC/20MCX	30%R/AR
OC-1024-20-20-50	ZnSe	25.4mm	6mm	20MCC/20MCX	50%R/AR
OC-1024-50	ZnSe	25.4mm	6mm	PO/PO	50%R/AR
OC-1122-20-15-50	ZnSe	27.94mm	5.59mm	20MCC/15MCX	50%R/AR
OC-1122-10-7.5-60	ZnSe	27.94mm	5.59mm	10MCC/7.5MCX	60%R/AR
OC-1124-15-9-55	ZnSe	27.94mm	6mm	15MCC/9MCX	55%R/AR
OC-1124-30-12-60	ZnSe	27.94mm	6mm	30MCC/12MCX	60%R/AR
OC-1124-20-9-60	ZnSe	27.94mm	6mm	20MCC/9MCX	60%R/AR
OC-1124-15-7.5-40	ZnSe	27.94mm	6mm	15MCC/7.5MCX	40%R/AR
OC-1124-15-7.5-50-ULA	ZnSe	27.94mm	6mm	15MCC/7.5MCX	ULA-50%R/ULA-AR
OC-1224-30-30-50	ZnSe	30.0mm	6mm	30MCC/30MCX	50%R/AR
OC-1524-10-10-30	ZnSe	38.1mm	6mm	10MCC/10MCX	30%R/AR
OC-1524-40	ZnSe	38.1mm	6mm	PO/PO	40%R/AR
OC-1524-20-30	ZnSe	38.1mm	6mm	20MCC/PO	30%R/AR
OC-1532-35-15-60	ZnSe	38.1mm	8mm	35MCC/15MCX	60%R/AR
OC-1532-35-15-70	ZnSe	38.1mm	8mm	35MCC/15MCX	70%R/AR
OC-1532-20-10-25	ZnSe	38.1mm	8mm	20MCC/10MCX	25%R/AR
OC-1532-20-10-50	ZnSe	38.1mm	8mm	20MCC/10MCX	50%R/AR
OC-1532-20-10-40	ZnSe	38.1mm	8mm	20MCC/10MCX	40%R/AR
OC-1532-15-7.5-40	ZnSe	38.1mm	8mm	15MCC/7.5MCX	40%R/AR
OC-1520-PO-20-55	ZnSe	38.1mm	5.08mm	PO/20MCC	55%R/AR
OC-2020-PO-20-50	ZnSe	50.8mm	5.08mm	PO/20MCC	50%R/AR
OC-2020-PO-15-65	ZnSe	50.8mm	5.08mm	PO/15MCC	65%R/AR
OC-2020-PO-20-65	ZnSe	50.8mm	5.08mm	PO/20MCC	65%R/AR
OC-2020-PO-15-80	ZnSe	50.8mm	5.08mm	PO/15MCC	80%R/AR
OC-2020-PO-20-55	ZnSe	50.8mm	5.08mm	PO/20MCC	55%R/AR
OC-55-6-PO-18-50	ZnSe	55mm	6mm	PO/18MCC	50%R/AR
OC-55-6-PO-20-50	ZnSe	55mm	6mm	PO/20MCC	50%R/AR
OC-55-8-65	ZnSe	55mm	8mm	PO/PO	65%R/AR
★The above are about standard products,they can also be custom made