Borate Crystals for Nonlinear Optical and Laser Applications: A Review

Abstract

e development of borate-based single crystals for laser and frequency conversion applications is reviewed. e basic idea behind nonlinear optics and the role of anionic groups in the borate crystals are summarized. e properties of borate crystals-BBO, LBO, CBO, KBBF, SBBO, CLBO, YCOB, GdCOB, GdYCOB, KAB and LCB-are discussed. e growth and characterization of several rare earth-based borate crystals are mainly focused. Several borate crystals are grown from the melt techniques and a few crystals are grown adopting the �ux technique. Many rare earth-based borate crystals are extensively used in device applications as they exhibit the frequency conversion ability along with high laser-induced damage tolerance.

Flux-Free Growth of β Barium Metaborate Single-Crystal Fibers by Micro-Pulling-Down Technique

“…Their application has extended to medicine, , science, , machining, and instrumentation in industries. − Indeed, the need for new coherent sources with wavelengths below 300 nm is becoming pressing and subjects these nonlinear crystals to very specific optical quality constraints. Efforts have been dedicated to borate-based crystals because of their structural properties, which are at the origin of their nonlinear optical (NLO) efficiencies. − In this family, barium metaborate (BBO), discovered in China by Chen et al, is one of the best NLO candidates. This material has considerably advanced the technology of ultraviolet frequency conversion (second-harmonic generation: SHG) and in optical parametric oscillator in the nanosecond and femtosecond ranges .…”

Double-ring coupled structure for efficient sum-frequency generation of longwave mid-infrared signal

“…Optical nonlinearities have served as the fundamental building blocks for numerous applications in classical and quantum optics [1] [2] . While the development of mid-infrared (MIR) sources is progressing, the production of low-noise room temperature detectors remains to be challenging [3] .…”

Synthesis and Crystal Structure of the Acentric Indium Borate InB6O9(OH)3

“…The intensive research on NLO borates began with the discovery of β-BaB 2 O 4 (BBO) and LiB 3 O 5 (LBO), which are still in use as NLO materials . Borates are not only superior to other NLO materials in UV and deep-UV applications but also more frequent to come by . The probability that a newly discovered crystal structure is acentric (which is a requirement for SHG) is more than twice as high in borates as in other inorganic compounds. , Most of the interesting NLO borates such as β-BaB 2 O 4 , LiB 3 O 5 , CsLiB 6 O 10 , K 2 Al 2 B 2 O 7 , or β-Rb 2 Al 2 B 2 O 7 feature isolated or adjunctive BO 3 groups as structural units .…”