With the development of laser technology, nonlinear optics plays a crucial role in frequency conversion. However, the generation of second harmonics in nonlinear optical crystals is generally subject to rigorous phase-matching conditions that hinder the performance of broadband tunability. It is believed that introducing disorders in nonlinear optical materials is helpful to overcome this obstacle. In this work, we have prepared a nonlinear microcrystal-doped glass (NMG) composite material, allowing for tunable and polarization-independent nonlinear conversion from visible to near-infrared. The linear dependence of SHG intensity versus sample thickness indicated the facilitation of random quasi-phase matching by using the NMG. Our results provide a more stable and promising platform for disordered nonlinear photonic materials and suggest the possibility of more efficient nonlinear conversions using the NMG composite glass fibers in future.

中文翻译：

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透明玻璃复合材料中的宽带非线性转换和随机准相位匹配

随着激光技术的发展，非线性光学在频率转换中发挥着至关重要的作用。然而，非线性光学晶体中二次谐波的产生通常受到严格的相位匹配条件的影响，这阻碍了宽带可调谐性能。人们认为，在非线性光学材料中引入紊乱有助于克服这一障碍。在这项工作中，我们制备了一种非线性微晶掺杂玻璃（NMG）复合材料，可以实现从可见光到近红外光的可调谐且与偏振无关的非线性转换。 SHG 强度与样品厚度的线性相关性表明使用 NMG 可以促进随机准相位匹配。我们的研究结果为无序非线性光子材料提供了一个更稳定、更有前景的平台，并表明未来使用 NMG 复合玻璃纤维进行更有效的非线性转换的可能性。