Froehly L, Courvoisier F, Mathis A, Jacquot M, Furfaro L, Giust R, Lacourt P A, Dudley J M
Département d’Optique P. M. Duffieux, Institut FEMTO-ST, UMR 6174 CNRSUniversité de Franche-Comté, 25030 Besançon, France.
Opt Express. 2011 Aug 15;19(17):16455-65. doi: 10.1364/OE.19.016455.
We generate arbitrary convex accelerating beams by direct application of an appropriate spatial phase profile on an incident Gaussian beam. The spatial phase calculation exploits the geometrical properties of optical caustics and the Legendre transform. Using this technique, accelerating sheet caustic beams with parabolic profiles (i.e. Airy beams), as well as quartic and logarithmic profiles are experimentally synthesized from an incident Gaussian beam, and we show compatibility with material processing applications using an imaging system to reduce the main intensity lobe at the caustic to sub-10 micron transverse dimension. By applying additional and rotational spatial phase, we generate caustic-bounded sheet and volume beams, which both show evidence of the recently predicted effect of abrupt autofocussing. In addition, an engineered accelerating profile with femtosecond pulses is applied to generate a curved zone of refractive index modification in glass. These latter results provide proof of principle demonstration of how this technique may yield new degrees of freedom in both nonlinear optics and femtosecond micromachining.
我们通过在入射高斯光束上直接施加适当的空间相位分布来生成任意凸加速光束。空间相位计算利用了光学焦散的几何特性和勒让德变换。利用该技术，从入射高斯光束实验合成了具有抛物线型（即艾里光束）以及四次和对数型分布的加速片状焦散光束，并且我们使用成像系统将焦散处的主强度瓣减小到亚10微米横向尺寸，展示了其与材料加工应用的兼容性。通过施加额外的旋转空间相位，我们生成了焦散限制的片状和体光束，两者都显示出最近预测的突然自聚焦效应的证据。此外，应用具有飞秒脉冲的工程加速分布在玻璃中产生折射率修改的弯曲区域。这些结果为该技术如何在非线性光学和飞秒微加工中产生新的自由度提供了原理验证。
