The study of nonlinear absorption has potential applications as saturable absorption and optical limiting character in scientific and engineering technology. In this work, we report on the Gaussian vortex beam z-scan to study the saturable absorption in the two-level model. For a given material and laser beam parameters, even though vortex beam shows less saturable absorption nature than the conventional Gaussian beam but not much appreciated. The open aperture z-scan peak is narrower for Gaussian vortex beam as compared with Gaussian beam. Also, in the presence of pico- and femto-second laser pulses, the central dark core of Gaussian vortex beam can provide a stable and accurate z-scan profile with avoiding thermal and other nonlinear optical effects at the beam waist of z-scan in the saturable absorber characterization. With including above mentioned points, we have shown how the Gaussian vortex z-scan is superior to the conventional Gaussian beam z-scan for saturable absorber characterization. Though discussed for single-photon absorption, it may extend to multi-photon absorption.

中文翻译：

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使用高斯涡旋光束 z 扫描的可饱和吸收的理论研究

非线性吸收的研究在科学和工程技术中具有作为饱和吸收和光限制特性的潜在应用。在这项工作中，我们报告了高斯涡旋光束 z 扫描，以研究两能级模型中的可饱和吸收。对于给定的材料和激光束参数，即使涡旋光束显示出比传统高斯光束更不饱和的吸收特性，但并没有得到太多的认可。与高斯光束相比，高斯涡旋光束的开孔 z 扫描峰更窄。此外，在存在皮秒和飞秒激光脉冲的情况下，高斯涡旋光束的中央暗核可以提供稳定和准确的 z 扫描轮廓，同时避免 z 扫描束腰处的热效应和其他非线性光学效应。可饱和吸收器表征。通过包括上述几点，我们已经展示了高斯涡旋 z 扫描如何优于传统的高斯光束 z 扫描以表征可饱和吸收体。虽然讨论了单光子吸收，但它可能扩展到多光子吸收。