Abstract

Break-up of a cw 632.8 nm wavelength laser beam to regular optical patterns during propagation through a photorefractive iron doped lithium niobate (LN:Fe) crystal is demonstrated. The power of the laser beam is varied in the range of 0.02–10 mW and 4 and 10 mm lengths LN:Fe crystals are used in the experiments. Time evolution of the laser beam profile at the output face of the LN:Fe crystal showed the splitting of a Gaussian beam into two lobes and then formation of 2D micrometric scale regular optical patterns. The input beam power increase essentially speeds-up the regular optical pattern formation. Regular optical patterns with two-fold rotation symmetry induct the quasi-crystalline photonic structures in LN:Fe crystal. A physical model to explain the experimental results is discussed.

中文翻译：

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在光折变铌酸锂晶体中将激光束分解成规则的光学图案和折射结构

摘要

演示了在通过光折变铁掺杂铌酸锂 (LN:Fe) 晶体传播期间，连续 632.8 nm 波长激光束分解为规则光学图案。激光束的功率在 0.02-10 mW 的范围内变化，实验中使用 4 和 10 毫米长的 LN:Fe 晶体。LN:Fe 晶体输出面的激光光束轮廓的时间演变表明，高斯光束分裂成两个瓣，然后形成二维微米尺度的规则光学图案。输入光束功率的增加实质上加速了规则光学图案的形成。具有两倍旋转对称性的规则光学图案在 LN:Fe 晶体中诱导准晶体光子结构。讨论了解释实验结果的物理模型。