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.

中文翻译：

---

Cr掺杂的Ca3NbGa3Si2O14：一种很有前途的近红外可调谐激光晶体

摘要 近红外波段宽幅可调谐固体激光器在光通信、人眼安全成像、医学和光谱学等领域具有重要应用，而Cr4+基激光器在该领域具有良好的应用前景。在此，我们报道了一种新型的 Cr 掺杂 Ca3NbGa3Si2O14 (Cr:CNGS) 近红外可调激光晶体。通过采用直拉法，生长了尺寸为 Φ 20 × 30 mm3 的 Cr:CNGS 单晶。对其晶体结构、光谱特性进行了详细研究。Cr:CNGS 具有吸引人的特性，包括 800-1400 nm 的宽发射带、长的荧光寿命（298 K 时为 18 μs）以及对 LD 泵浦源的良好适应性，所有这些特性使其成为近红外可调谐激光器的潜在激光晶体。尤其，