Cr-doped Ca3NbGa3Si2O14: A promising near-infrared tunable laser crystal

Abstract Broad tunable solid-state lasers in the near-infrared region are urgently demanded due to their critical applications in optical communications, eye-safe imaging, medicine and spectroscopy, and Cr4+-based lasers exhibit good application prospect in this area. Herein, we reported a new near-infrared tunable laser crystal of Cr-doped Ca3NbGa3Si2O14 (Cr:CNGS). By employing the Czochralski method, single crystal of Cr:CNGS with dimensions of Φ 20 × 30 mm3 was grown. Its crystal structure, spectral properties were investigated in detail., Cr:CNGS exhibits attractive properties, including broad emission band at 800–1400 nm, long fluorescence lifetime (18 μs at 298 K) and good adaptability to LD pumping source, all of these characteristics enable it to be a potential laser crystal for the near-infrared tunable lasers. Notably, we discovered that the multi-sites in CNGS crystal make Cr ions exist in different valence states simultaneously, including Cr3+, Cr4+ and Cr5+, which is also partly responsible for its broadband emission.