In photonics since 1999. Benelux technical support, answer within one working day.
Mirrors, beamsplitters, polarisation and surviving the power density.
A laser damage threshold is only meaningful together with the wavelength, the pulse duration and the number of pulses it was measured at. A figure in joules per square centimetre for a 10 ns pulse at 1064 nm says almost nothing about your femtosecond system.
A polarising beamsplitter cube transmits one linear polarisation and reflects the other. Extinction ratio describes how cleanly it does so, and it is almost always much better in transmission than in reflection. Combine one with a half-wave plate and you have a continuously variable power splitter.
A metallic mirror reflects broadly at around 96 to 98 per cent and tolerates being cleaned. A dielectric stack reflects above 99,5 per cent but only over a designed band and angle range. For a single laser line, use dielectric. For white light or several wavelengths at once, use metal.
