Beamsplitter plate is an optical window with semi-transparent mirrored coating to break a beam into two separate beams. A beamsplitter will reflect a portion of the incident energy, abs..

Specifications:

Material: ------------------------BK7 grade A, optical glass
Dimension Tolerance:------------------------------±0.2mm
Thickness Tolerance: ------------------------------±0.2mm
Flatness: ------------------------------------ λ /4 @ 632.8 nm
Surface Quality: ---------------------60/40 scratch and dig
Parallelism: ------------------------------------ <1 arc minute
T/R:--------------------50/50±5%, for random polarization
       -------------------------------T=(Ts+Tp)/2, R=(Rs+Rp)/2
Coatings: (Incidence angle: 45 degree)
Surface1: --------- Single wavelength partial reflectance
Surface2: ---------------------------------------------AR coating 
Standard Coating wavelength:
Narrow Band: ---------488, 532, 632.8, 650, 808, 850, 980, 1064, 1310, 1550 nm
Broadband: -------------450-650, 650-900, 900-1200, 1200-1550, 1500-1610 nm

Standard Size:
 

Part No, - wavelength
For example, BSP1203 - 1500-1610,
Beamsplitter 10X10mm, 1500-1610 nm broadband coating