Light Induced Self Assembled Colloidal Systems

光可以在微观尺度上移动透明物体。这是因为物体可能会像一个小透镜一样，弯曲光线，改变其动量。这会使粒子保持在光场中最亮的部分。然而，如果我们使用两束相对的光束来容纳不止一个粒子，就会产生有趣的效果：一个物体弯曲的光的作用会影响另一个球体的光分布，从而影响另一个球体的平衡位置，从而产生一个相互距离为许多微米的物体链：光学束缚物质。在含有许多微观粒子的系统中，可能会出现其他有趣的效应。如果我们照亮一大群这样的物体，它们自然会形成图案，例如将自己组织成直线。对于比照明光更大的物体来说，这是因为每个物体都像一个透镜一样，重新聚焦光线，并将邻近的物体拉在一起：这种效应与非线性物理有着错综复杂的联系，这是一种相对较新的介质，可以在其中观察孤立子等现象：波的行为像粒子，实际上可能没有任何传播。我们的目标是全面了解这些效应，并打破对光学结合和这些非线性效应的理解。我们将实现二维和三维的光学绑定，并使用染料来成像系统中的光分布。这些研究可能会导致新的方法将细胞结合在一起，将大面积的胶体颗粒组织起来，以及其他物体创造出被困物体的有序自组装。这种自组装和了解其背后的原因对于自下而上创造更大晶体的方法是有用的

Light can move transparent objects at the microscopic scale. This occurs as the object may act like a small lens and bend the light and change its momentum. This causes the particle to be held in the brightest part of the light field. However interesting effects can occur if we use two opposing beams to hold a more than one particle: the very action of the light bent by one object influences the light distribution and thus equilibrium position of the other sphere creating a chain of objects held at distances of many microns from one another: optically bound matter. In systems with many microscopic particles other interesting effects may occur. If we illuminate a large group of such objects they naturally form patterns e.g. organise themselves into lines. For objects larger than the illuminating light, this occurs as each object acts like a lens and refocuses the light and pulls neigbouring objects together: This effect is intricately linked to nonlinear physics and this is a relatively new medium within which to observe phenomena such as solitons: waves that act like particles and in fact may move without any spreading. We aim to fully understand these effects and unfiy the understanding of optical binding and these nonlinear effects. We will realise optical binding in 2 and 3 dimensions as well as use a dye to image the light distribution in the system. The studies may lead to new ways to bind together cells, orgnaise colloidal particles over a large area and other objects creating self assembly of trapped objects to order. Such self assembly and understanding the reasons behind it is useful fora bottom up approach to creating larger crystals