Abstract The present work reports the study on nonlinear absorbing behavior of optically nonlinear m-nitroaniline (mNA) organic molecules properly oriented in the core of a polymeric fiber such as Poly (methyl methacrylate) (PMMA) and Poly (ethylene Oxide) (PEO) free standing films synthesized by electrospinning technique for the first time. The nonlinear absorption nature of the nanofibers is investigated by intensity dependent Z scan technique (532 nm, 10 Hz, 5ns). We observed an unusual nonlinear switching behavior in mNA- PMMA nanofiber from reverse saturable absorption (RSA) to saturable absorption (SA) through a peculiar W-pattern for an increase in pulse energy, whereas intensity dependent SA behavior is seen clearly in mNA–PEO polymer matrix. The identified nonlinear absorption of mNA –PMMA and mNA -PEO fibers can be of interest for various optical applications such as switching, optical sensors, etc. The normalized transmittance versus input fluence graph confirms the potential possibility of using the prepared fibers as optical switches at higher intensity. And mNA – PMMA fiber matrix at low intensities exhibits an optical limiting behavior, implying that the material to be a potential candidate for laser safety devices. Demonstrated fiber matrix free standing films are of potential use as it finds direct application in laser photonic devices.

中文翻译：

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电纺间硝基苯胺纳米纤维的强度相关非线性吸收切换行为

摘要 目前的工作报告了在聚合物纤维如聚（甲基丙烯酸甲酯）（PMMA）和聚（环氧乙烷）（PEO）中正确定向的光学非线性间硝基苯胺（mNA）有机分子的非线性吸收行为的研究。首次通过静电纺丝技术合成的独立薄膜。通过强度相关的 Z 扫描技术 (532 nm, 10 Hz, 5ns) 研究了纳米纤维的非线性吸收性质。我们观察到 mNA-PMMA 纳米纤维通过特殊的 W 模式从反向饱和吸收 (RSA) 到饱和吸收 (SA) 中异常的非线性转换行为，以增加脉冲能量，而在 mNA-PEO 中可以清楚地看到强度相关的 SA 行为聚合物基质。mNA -PMMA 和 mNA -PEO 光纤的已识别非线性吸收对于各种光学应用（例如开关、光学传感器等）具有重要意义。归一化透射率与输入注量图证实了在更高的强度。并且 mNA – PMMA 纤维基质在低强度下表现出光学限制行为，这意味着该材料是激光安全装置的潜在候选材料。已证明的纤维基质独立薄膜具有潜在用途，因为它可以直接应用于激光光子器件。并且 mNA – PMMA 纤维基质在低强度下表现出光学限制行为，这意味着该材料是激光安全装置的潜在候选材料。已证明的纤维基质独立薄膜具有潜在用途，因为它可以直接应用于激光光子器件。并且 mNA – PMMA 纤维基质在低强度下表现出光学限制行为，这意味着该材料是激光安全装置的潜在候选材料。已证明的纤维基质独立薄膜具有潜在用途，因为它可以直接应用于激光光子器件。