Adaptive slit beam shaping for direct laser written waveguides
Adaptive slit beam shaping for direct laser written waveguides
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DOI：
10.1364/ol.37.000470
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发表时间：
2012-02-15
期刊：
影响因子：
3.6
通讯作者：
Booth, M. J.
中科院分区：
文献类型：
--
作者：
Salter, P. S.;Jesacher, A.;Booth, M. J.
我们演示了一种改进的飞秒激光写入法在块状材料中制备光波导的方法。我们使用LC空间光调制器（SLM）通过在物镜的瞳孔中产生自适应狭缝照明来塑造光束焦点。衍射光栅在SLM上的条带中应用，以模拟狭缝，第一个衍射阶映射到物镜的瞳孔平面上，而第零阶被阻挡。该技术可以在写入过程中实时控制波束成形参数，比使用非自适应方法更容易制造更复杂的结构。在熔融石英中，波导与单模光纤的耦合损耗为0.2至0.5 dB，传播损耗为0.5 dB
We demonstrate an improved method for fabricating optical waveguides in bulk materials by means of femtosecond laser writing. We use an LC spatial light modulator (SLM) to shape the beam focus by generating adaptive slit illumination in the pupil of the objective lens. A diffraction grating is applied in a strip across the SLM to simulate a slit, with the first diffracted order mapped onto the pupil plane of the objective lens while the zeroth order is blocked. This technique enables real-time control of the beam-shaping parameters during writing, facilitating the fabrication of more complicated structures than is possible using nonadaptive methods. Waveguides are demonstrated in fused silica with a coupling loss to single-mode fibers in the range of 0.2 to 0.5 dB and propagation loss