We report the first investigation results of the nonlinear optical properties of As₂Te₃. More specifically, the nonlinear optical absorption properties of the prepared α-As₂Te₃ were investigated at wavelengths of 1.56 and 1.9 μm using the open-aperture (OA) Z-scan technique. Using the OA Z-scan technique, the nonlinear absorption coefficients (β) of α-As₂Te₃ were estimated in a range from (− 54.8 ± 3.4) × 10⁴ cm/GW to (− 4.9 ± 0.4) × 10⁴ cm/GW depending on the irradiance of the input beam at 1.56 μm, whereas the values did from (− 19.8 ± 0.8) × 10⁴ cm/GW to (− 3.2 ± 0.1) × 10⁴ cm/GW at 1.9 μm. In particular, the β value at 1.56 μm is an order of magnitude larger than the previously reported values of other group-15 sesquichalcogenides such as Bi₂Se_3, Bi₂Te_3, and Bi₂TeSe₂. Furthermore, this is the first time report on β value of a group-15 sesquichalcogenide at a 1.9-μm wavelength. The density functional theory (DFT) calculations of the electronic band structures of α-As₂Te₃ were also conducted to obtain a better understanding of their energy band structure. The DFT calculations indicated that α-As₂Te₃ possess sufficient optical absorption in a wide wavelength region, including 1.5 μm, 1.9 μm, and beyond (up to 3.7 μm). Using both the measured nonlinear absorption coefficients and the theoretically obtained refractive indices from the DFT calculations, the imaginary parts of the third-order optical susceptibilities (Im χ⁽³⁾) of As₂Te₃ were estimated and they were found to vary from (− 39 ± 2.4) × 10^–19 m²/V² to (− 3.5 ± 0.3) × 10^–19 m²/V² at 1.56 μm and (− 16.5 ± 0.7) × 10^–19 m²/V² to (− 2.7 ± 0.1) × 10^–19 m²/V² at 1.9 μm, respectively, depending on the irradiance of the input beam. Finally, the feasibility of using α-As₂Te₃ for SAs was investigated, and the prepared SAs were thus tested by incorporating them into an erbium (Er)-doped fiber cavity and a thulium–holmium (Tm–Ho) co-doped fiber cavity for both 1.5 and 1.9 μm operation.

我们报告了 As ₂ Te ₃非线性光学特性的首次研究结果。更具体地说，使用开放孔径 (OA) Z 扫描技术在 1.56 和 1.9 μm 的波长下研究了制备的 α-As ₂ Te ₃的非线性光学吸收特性。使用 OA Z-scan 技术，α-As ₂ Te ₃的非线性吸收系数 (β)估计在 (− 54.8 ± 3.4) × 10 ⁴  cm/GW 到 (− 4.9 ± 0.4) × 10 ^{4 的范围内} cm/GW 取决于输入光束在 1.56 μm 处的辐照度，而值从 (− 19.8 ± 0.8) × 10 ⁴  cm/GW 到 (− 3.2 ± 0.1) × 10 ⁴ cm/GW 在 1.9 μm。特别是，1.56 μm 处的 β 值比之前报道的其他第 15 组倍半硫族化物（例如 Bi ₂ Se _3、 Bi ₂ Te ₃和 Bi ₂ TeSe _{2 ）的}值大一个数量级。此外，这是第一次报告 15 族倍半硫属化物在 1.9-μm 波长下的 β 值。还进行了 α-As ₂ Te ₃电子能带结构的密度泛函理论 (DFT) 计算，以更好地了解它们的能带结构。DFT 计算表明，α-As ₂ Te ₃在包括 1.5 μm、1.9 μm 及以上（高达 3.7 μm）的宽波长范围内具有足够的光吸收。使用测得的非线性吸收系数和从 DFT 计算中理论上获得的折射率，估计了 As ₂ Te ₃的三阶光学磁化率 (Im χ ⁽³⁾ )的虚部，发现它们从 ( − 39 ± 2.4) × 10 ^–19 m ² /V ²至 (- 3.5 ± 0.3) × 10 ^–19 m ² /V ² at 1.56 μm 和 (- 16.5 ± 0.7) × 10 ^–19 m ² /V ²至(− 2.7 ± 0.1) × 10 ^–19m ² /V ²分别为 1.9 μm，具体取决于输入光束的辐照度。最后，研究了将 α-As ₂ Te ₃用于 SAs的可行性，并通过将它们掺入掺铒 (Er) 光纤腔和铥-钬 (Tm-Ho) 共掺杂来测试制备的 SAs。用于 1.5 和 1.9 μm 操作的光纤腔。