Abstract
Borates have long been recognized as a very important family of nonlinear optical (NLO) crystals, and have been widely used in the laser frequency-converting technology in ultraviolet (UV) and deep-ultraviolet (DUV) regions. In this work, the borate-based UV and DUV NLO crystals discovered in the recent decade are reviewed, and the structure–property relationship in the representative borate-based UV and DUV NLO crystals is analyzed. It is concluded that the optical properties of these crystals can be well explained directly from the types and spatial arrangements of B-O groups. The deduced mechanism understanding has significant implications for the exploration and design of new borate-based crystals with excellent UV and DUV NLO performance.
Highlights
In 1961, Franken and his co-workers observed the phenomenon of second-harmonic generation (SHG) in quartz [1]
Borate Crystals in Which the B-O Groups Are (BO3 )3− Groups Only. According to their structural features, the types of borates discovered in the recent decade can mainly be catalogued into three classes: KBe2 BO3 F2 (KBBF)-type, Sr2 Be2 B2 O7 (SBBO)-type and three-dimensional network crystals
Both of them have very large energy bandgap (Eg ~ 9.5 eV) or extremely short knowledge, the only known compound in this type of borates is LaBeB3O7, which was synthesized in absorption edge
Summary
In 1961, Franken and his co-workers observed the phenomenon of second-harmonic generation (SHG) in quartz [1]. The relatively narrow energy bandgap (Eg ~ 6.5 eV or λcutoff ~190 nm) in BBO and the small birefringence value (∆n ~0.04 @ 400 nm) in LBO restrict their applications in the DUV region. 0.07 ~ 0.08 @ 400 nm, and the shortest SHG phase-matching wavelengths are 161 nm, 170 nm and 201 nm for KBBF, RBBF and CBBF, respectively [25] This clearly indicates the excellence for the KBBF family crystals used as the DUV NLO crystals. Since the beginning of this century, quite a few new borate-based UV or DUV NLO compounds have been synthesized They exhibit wide energy bandgaps and large NLO effects accompany with the diverse structural features. Based on the analysis and summarization, the prospects for UV and DUV NLO borates are discussed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
