Design of Deep-Ultraviolet Zero-Order Waveplate Materials by Rational Assembly of [AlO 2 F 4 ] and [SO 4 ] Groups.

Zero-order waveplates are widely used in the manufacture of laser polarizer waves, which are important in polarimetry and the laser industry. However, there are still challenges in designing deep-ultraviolet (DUV) waveplate materials that satisfy large band gaps and small optical anisotropy simultaneously. Herein, three cases of aluminum sulfate fluorides: Na 2 AlSO 4 F 3 , Li 4 NH 4 Al(SO 4 ) 2 F 4 , and Li 6 K 3 Al(SO 4 ) 4 F 4 , with novel [AlSO 4 F 3 ] layers or isolated [AlS 2 O 8 F 4 ] trimers were designed and synthesized by the rational assembly of [AlO 2 F 4 ] and [SO 4 ] groups through a hydrothermal method. Experiments and theoretical calculations imply that these three possess short cutoff edges (λ < 200 nm) and small birefringence (0.0014-0.0076 @ 1064 nm), which fulfils the prerequisite for potential DUV zero-order waveplate materials. This work extends the exploration of DUV zero-order waveplate materials to the aluminum sulfate fluoride systems.