Vacuum ultraviolet (VUV, 100–200 nm) light sources are crucial for advanced spectroscopy, quantum research and semiconductor lithography
,
,
. Compared with conventional large-scale VUV generation technologies
,
,
,
, second-harmonic generation (SHG) through nonlinear optical (NLO) crystals
,
,
is the simplest and most efficient method. However, the scarcity of suitable NLO crystals has constrained the production of VUV light through SHG: existing materials fail to meet phase-matching requirements, suffer from low conversion efficiency or have severe growth limitations
,
,
,
,
,
,
,
,
. In this study, we report the development of the fluorooxoborate crystal NH4B4O6F (abbreviated as ABF) as a promising material for VUV light generation. VUV devices with specific phase-matching angles were constructed, achieving a record 158.9-nm light through phase-matching SHG and a maximum nanosecond pulse energy of 4.8 mJ at 177.3 nm with a conversion efficiency of 5.9%. The enhanced NLO performance is attributed to optimized arrangements of fluorine-based units creating asymmetric sublattices. This work provides further material in the NLO field, with potential for applications in compact, high-power VUV lasers using ABF.
