Beam combiner is a kind of partial refection mirror. It combines two or more wavelengths to one light path. As good quality fused silica is used and optimal design film is coated, normally beam combiner transmit IR wavelength and reflect visible wavelength.
For example, YAG beam combiner is mainly used in system alignment by laser diode. Designed for AOI 45 deg, they transmit 1064nm laser beam and calibrate it with 90 degree reflected laser diode beam.
| ATTRIBUTE | SPECIFICATIONS |
| material | Fused Silica or Specified |
| DIAMETER TOLERANCE | +0.1, -0.1mm |
| thickness TOLERANCE | +/-0.1mm |
| parallelism | <1 arc minute |
| CLEAR APERTURE | >90% |
| flatness | λ/2@6332.8nm per 25.4mm |
| SURFACE FIGURE: IRREGULARITY(N) | <0.5 fringe |
| SURFACE QUALITY | 40/20 scratch and dig |
| BEVEL | < 0.2 mm x 45° |
| COATING | Surface 1: With AR coating @ IR wavelength Surface 2: With HR coating @ visible wavelength @ 45 Degree |
