Advantageous growth characteristics and properties of SrAlF5 compared with BaMgF4 for UV/VUV nonlinear optical applications

The growth characteristics of large size SrAlF5 and BaMgF4 single crystals by the Czochralski technique are described and compared. Transmission spectra in the vacuum ultraviolet wavelength region indicate a high transparency of SrAlF5 (about 90% without considering surface reflection loses) down to 150 nm, in contrast to the optical loses observed for BaMgF4. The ferroelectric character of SrAlF5 is evidenced by the reversal of the spontaneous polarization in a hysteresis loop. The higher potential of SrAlF5 in comparison with BaMgF4 for the realization of all-solid-state lasers in the ultraviolet wavelength region by the quasi-phase matching technique is pointed out. SrAlF5, besides a higher grade of transparency, shows a nonlinear effective coefficient similar to that of quartz and uniaxial nature, in contrast to the one-order smaller nonlinear coefficient and biaxial character of BaMgF4.