Partially reflective optics are useful in many laser systems.

Output windows are coated with a specific reflectivity thin film to allow feedback into the laser cavity. For CO2 lasers a ZnSe part between 40 - 80 percent reflective is generally used. These are one of the most critical and sensitive elements of a laser system. We stock many such parts, included mounts where appropriate.

Leaky mirrors are coated such that just 1 percent or less of the incident power is transmitted. This small power level can be used for on line power monitoring in real time. A wide range of "rear" mirrors for most CO2 lasers are stocked.

Beam splitters are used at 45 degrees incidence, and split the beam into 2 perpendicular beams. 50/50 is a common ratio. Note these parts are generally polarisation sensitive. It is also possible to use knife edge mirror or a roof prism to physically split a laser beam.