Adaptive optics in an optical trapping system for enhanced lateral trap stiffness at depth
Adaptive optics in an optical trapping system for enhanced lateral trap stiffness at depth
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DOI：
10.1088/2040-8978/15/7/075305
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发表时间：
2013-07
影响因子：
2.1
通讯作者：
M. Müllenbroich;N. McAlinden;Amanda J. Wright
中科院分区：
文献类型：
--
作者：
M. Müllenbroich;N. McAlinden;Amanda J. Wright
在光阱系统中，由于光学像差和系统未对准，阱刚度或弹簧常数随阱深度急剧恶化。这会严重阻碍使用光镊进行精确定量测量的研究。在这里，可变形膜反射镜，结合随机搜索算法，以纠正这些像差，通过优化的品质因数，这是直接成比例的陷阱刚度。以前的研究试图解决这个问题，但没有一个使用的价值因素，是直接成比例的陷阱刚度。我们证明，横向陷阱刚度，测量和不像差校正在增加的深度，提高了整个传统陷阱的捕获范围，并允许我们扩展的最大深度，我们可以陷阱从136到166 μm。在131 μm的深度处，陷阱刚度对于x轴和y轴分别提高了4.37和3.31倍。像差校正导致可变形膜反射镜形状，其中单个形状可以应用于整个宽范围的陷阱深度，显示出显著的改善，并且具有使横向捕获力在x和y上更均匀的附加益处。
In optical trapping systems the trap stiffness, or spring constant, deteriorates dramatically with trap depth due to optical aberrations and system misalignment. This can severely hamper studies that employ optical tweezers to make accurate quantitative measurements. Here, a deformable membrane mirror is used, in conjunction with a random search algorithm, to correct for these aberrations by optimizing on a merit factor that is directly proportional to the trap stiffness. Previous studies have sought to address this issue but none have used a merit factor that is directly proportional to the trap stiffness. We demonstrate that the lateral trap stiffness, measured with and without aberration correction at increasing depths, improves throughout the trapping range of a conventional trap and allows us to extend the maximum depth at which we can trap from 136 to 166 μm. At a depth of 131 μm, trap stiffness improved by factors of 4.37 and 3.31 for the x- and y-axes respectively. The aberration correction resulted in deformable membrane mirror shapes where a single shape could be applied throughout a wide range of trap depths, showing significant improvement, and had the added benefit of making the lateral trapping forces more uniform in x and y.