Our beamsplitting optics are designed for splitting or combining laser beams, which commonly have S-polarized output in a typical scientific setup. S-polarization will be equally split with R/T = 50/50 at 45° incidence. P-polarized beams will be split 30/70 (R/T). Unpolarized light will be split 40/60 (R/T) on average.

Beamsplitters are available with a wide selection of broadband dielectric coatings on the reflecting surface and matching anti-reflection coatings on the back surface. Each set of coatings is essentially achromatic across a wide spectral band so that a single optic will work for the entire range of a particular tunable laser, for several laser diode wavelengths, or for most visible laser wavelengths. BS.1 covers the 480-700 nm spectral range, BS.2 covers the 700-950 nm spectral range and BS.3 covers the 1290-1580 nm spectral range.

N-BK7 is an excellent lens material for general use such as most visible and near infrared applications. It is the most common borosilicate crown optical glass, and it provides great performance at a good value. Its high homogeneity, low bubble and inclusion content, and straightforward manufacturability make it a good choice for transmissive optics.

UV Grade Fused Silica is synthetic amorphous silicon dioxide of extremely high purity providing maximum transmission from 195 to 2100 nm. This non-crystalline, colorless silica glass combines a very low thermal expansion coefficient with good optical qualities, and excellent transmittance in the ultraviolet region. Transmission and homogeneity exceed those of crystalline quartz without the problems of orientation and temperature instability inherent in the crystalline form. It will not fluoresce under UV light and is resistant to radiation. For high-energy applications, the extreme purity of fused silica eliminates microscopic defect sites that could lead to laser damage.

Optics with perfectly parallel faces are unsuited for use as reference elements in laser setups as reflections from both surfaces would be collinear resulting in undesired large period fringes. Introduction of a slight wedge causes unwanted reflections from the second surface to be deflected from the optical path. An arrow on the side points to the non-wedged side (S1) of the beamsplitter, where has the BS.x beamsplitter coating.

An antireflection coating NC.x is applied on the back surface to minimize ghost reflections. Three broadband AR coatings are offered and optimized for 45° angle of incidence beams with <0.75% reflectance. NC.1 covers the 440-700 nm spectral range, NC.2 covers the 660-1000 nm spectral range and NC.3 covers the 1010-1550 nm spectral range.