3D Laser Beam Shaping: The True Potential of Laser Based Manufacturing

激光制造已经从20世纪50年代和60年代的纯粹科幻小说的想法发展成为一个真实的世界，在制造大量产品中的关键一步。多年来，世界各地的研究实验室和公司开发了一系列新技术和新工艺。其中最重要的是光束整形技术的发展。材料的激光加工是通过将能量从激光束转移到材料中来驱动的，并且可以是热、光化学和光学非线性效应的混合。通过改变激光束在其影响材料的地方的形状，可以塑造能量如何以及在何处转移。这样就可以更精确地控制激光与材料的相互作用，从而更精确地控制制造过程本身。这使得切割、焊接和类似工艺的工作方式得到改进，质量和效率得到提高。然而，这些波束成形技术是有限的。它们仅在二维中成形，即在单个焦平面中成形。这对于“表面处理”来说不是一个大问题，因为激光束形成正确形状的平面可以被制成材料的表面，在聚焦光束时要小心。然而，对于具有不规则形状、不精确厚度或对激光至少部分透明的材料，这是一个挑战。当试图利用基于非线性现象的一系列令人兴奋的新技术时，这也是一个挑战。非线性激光工艺通常将激光材料相互作用限制在仅激光束的具有极高强度的那些区域，即在焦点处。通过将焦点移动到材料内部，就可以从内到外进行制造。然而，由于光不仅在表面上而且在整个焦点体积中与材料相互作用，因此二维光束整形是不够的;相反，需要完全的3D控制。在这个研究项目中，我们将利用光的波动性质。通过玻璃光学器件的仔细成形，可以使激光束的不同部分弯曲以受控方式重叠。当光束重叠时，它们将干涉，产生高能量和低能量的区域。通过仔细计算，可以使用设计为提供精确干涉图案的每个光学器件来操纵这一点，从而导致特定的能量分布;在三维中塑造光束。通过在整个聚焦区域成形激光束，将有可能开辟全新的制造方法，从更有效的手段切割钢化玻璃（如移动的手机或iPad），切割和钻孔半导体（用于计算机芯片），制造精密医疗设备，并创造新的和更有效的外科手术。潜在的应用是真正巨大的，变革性的，并将改变我们可以制造的方式和内容。

Manufacturing with lasers has advanced from the purely science fiction ideas of the 1950's and 60's to be a real world, critical step, in the manufacture of an enormous range of products. Over the years a range of new techniques and processes have been developed in research labs and companies across the world. One of the more important of these has been the development of beam-shaping technology.Laser processing of material is driven by transfer of energy from the laser beam into the material, and can be a mixture of thermal, photo-chemical and optical non-linear effects. By changing the shape of a laser beam where it impacts a material it is possible to mould how and where energy is transferred. This then allows for more precise control of the laser-material interaction and hence of the manufacturing process itself. This has led to improvements in the way cutting, welding and similar processes work with improvements in quality and efficiency. However these beam-shaping technologies are limited. They only shape in two dimensions, i.e. in a single focal plane. This is not a big problem for "surface processes" as the plane at which the laser beam is formed into the right shape can be made, with some care in focussing the beam, to be the surface of the material. However for materials with an irregular shape, imprecise thicknesses, or that are at least partially transparent to the laser, this is a challenge. It is also a challenge when trying to take advantage of the range of exciting new technologies based on non-linear phenomena. Non-linear laser processes typically limit the laser material interaction to only those regions of the laser beam where there is an extremely high intensity i.e. at the focus. By moving the focus inside the material it then possible to manufacture from the inside out. However, because the light interacts with the material not just on the surface but throughout the focal volume two dimensional beam shaping is insufficient; full 3D control is instead required. Within this research project we will take advantage of the wave-nature of light. Through careful shaping of a glass optic it is possible to bend different parts of a laser beam to overlap in a controlled manner. As the beams overlap they will interfere creating regions of high and low energy. Though careful calculation it is possible to manipulate this with each optic designed to give a precise interference pattern which results in a specific energy distribution; to shape the beam in three dimensions. By shaping the laser beam throughout the focal region it will be possible to open entirely new methods of manufacture from more effective means to cut toughened glass (like mobile phones or iPads), dice and drill semiconductors (for computer chips), make precision medical devices, and create new and much more effective surgical procedures. The potential applications are truly enormous, transformative and will change how and what we can manufacture.