Broadband thin-film polarizer for 12 fs applications

A broadband non-dispersive thin-film polarizer for ultrafast applications is presented. The polarizer has a controllable flat-phase and a high extinction ratio of 23:1 in the working bandwidth from 680 nm to 900 nm. This bandwidth allows supporting laser pulses down to 12 fs. The unavoidable mechanical stress of the interference coating is completely compensated by a specially designed antireflection coating on the second side of the substrate, allowing the use of thin substrates.