Beamsplitters allow partial reflectance at a 45° angle of incidence with a 10.6μm wavelength. Only a certain percentage of incident energy is reflected while the remaining incident energy is transmitted.
A beam splitter is an optical device that splits a beam of light in two.It reflects incident light at a certain percentage and allows the rest to transmit.
Most beamsplitter coatings are highly polarization sensitive. Thus, if the source's polarization state varies with time, as in some randomly polarized lasers, the beamsplitters transmission will also vary with time.

Specifications
Material	Zinc Selenide (ZnSe)  CVD Laser Grade
Diameter Tolerances	+.000" , -.005"
Thickness Tolerances	±.010"
Parallelism	</= 30arc seconds
Surface Quality	< 40/20 scratch – dig Laser Finish
Spectral Performance
SIDE 1	Reflectance and tolerance listed as below
1-10%       ±1.0%
11-85%    ±1.0%  (±0.5% can be achieved)
86-95%      ±1.0%
96-99%      ±1.0%
SIDE 2
Standard high efficiency low loss anti-reflectance
AR-coating for 10.6μm
Total finish part Absorption < .15%
Angle Of Incidence	45°

P/N	Dia	THK	%Reflectance	Polarization
BSPZ-1012-33-P	25.4mm	3.04mm	33.3%	P-POL
BSPZ-1012-33-S	25.4mm	3.04mm	33.3%	S-POL
BSPZ-1112-33-P	27.94mm	3.04mm	33.3%	P-POL
BSPZ-1112-33-S	27.94mm	3.04mm	33.3%	S-POL
BSPZ-1516-33-P	38.1mm	4.06mm	33.3%	P-POL
BSPZ-1516-33-S	38.1mm	4.06mm	33.3%	S-POL
BSPZ-1012-50-P	25.4mm	3.04mm	50%	P-POL
BSPZ-1012-50-S	25.4mm	3.04mm	50%	S-POL
BSPZ-1112-50-P	27.94mm	3.04mm	50%	P-POL
BSPZ-1112-50-S	27.94mm	3.04mm	50%	S-POL
BSPZ-1516-50-P	38.1mm	4.06mm	50%	P-POL
BSPZ-1516-50-S	38.1mm	4.06mm	50%	S-POL
BSPZ-1012-98-P	25.4mm	3.04mm	98%	P-POL
BSPZ-1012-98-S	25.4mm	3.04mm	98%	S-POL
BSPZ-1112-98-P	27.94mm	3.04mm	98%	P-POL
BSPZ-1112-98-S	27.94mm	3.04mm	98%	S-POL
BSPZ-1516-98-P	38.1mm	4.06mm	98%	P-POL
BSPZ-1516-98-S	38.1mm	4.06mm	98%	S-POL
BSPZ-2020-50-P	50.8mm	5.08mm	50%	P-POL
BSPZ-2020-50-S	50.8mm	5.08mm	50%	S-POL

★The above are about standard products,they can also be custom made
★S-s-polarization,P-p-polarization

Substrate	(%)Reflectivity @ Normal Incidence	(%)Reflectivity @ 45°AOI S-Pol	(%)Reflectivity @ 45°AOI P-Pol	(%)Reflectivity @ 45°AOI R-Pol
Znse	0.2	<=2.0	<=5.0	<=1.5
Znse	40	52.6	21.3	37
Znse	50	62.7	29.3	46
Znse	55	66.1	30.7	48.2
Znse	60	72	38.6	55.3
Znse	65	74.9	40.4	57.6
Znse	70	79	45.2	62.1
Znse	75	83.2	50.8	67
Znse	80	87.1	57.5	72.3
Znse	85	91.1	65.8	78.5
Znse	90	92.7	67	79.8
Znse	95	97.3	82.1	89.7
Znse	99	99.1	91.5	95.1
Znse	99.5	99.8	93.8	96.5