3-6  µm dispersive mirrors compensating for dispersion introduced by the GaAs crystal

A new broadband dispersive mirror (DM), which consists of Si and SiO₂ layer materials operating in the spectral range of 3-6 µm, is developed for the first time, to our knowledge. The DM is able to compensate for the dispersion of a 0.5 mm thick GaAs crystal per bounce. Pulse analysis proves that the compensation effect of the DM is much better than a CaF₂ plate, which is the commonly used dispersion compensation element in mid-infrared optical parametric oscillators (MIR OPOs), and the new MIR DM could improve the MIR OPO spectrum with better pulse quality and short pulse duration.