Ptychographic inversion algorithms for intensity data in various experimental configurations.

该项目是关于一种名为光刻的计算成像技术的新应用。光刻最初是一种解决衍射图中的相位问题的方法。与全息术类似，它可以测量散射波的相位和强度。但是，这种方法现在被认为在只能测量图像的情况下有更广泛的应用。其他的发展意味着，它还可以处理成像实验中所称的“多模式”(在一个数据集中出现两种不相关的图像现象)，如振荡的“混合状态”。该方法使用与“传统”层析成像中使用的相同核心反转算法的变体。该项目的具体目标将是了解这些算法在强度类型的层析成像反演中的性能限制。这种通用技术的应用可能包括提高天文望远镜的分辨率性能，解决非等面积盲反卷积问题的新方法，以及利用其模式特性进行消息加密。如果计算成功，算法将在光学台上收集的模型数据上进行测试。到目前为止，最初的工作主要集中在层析的基本不对称性上。在“实空间”光刻中，测量的是衍射图案的强度，在“傅立叶光刻”中，测量的是图像的强度。根据互易原理，这两种类型的数据应该包含相同的信息，而实际上，在这些不同模式下的相位和模数重建的质量非常不均匀(在实空间层析中，相位质量好，模数差，而对于傅里叶层析，反之亦然)。我们已经确定了原因，现在正在努力修正相关的重建算法，以克服该技术中的这一根本限制。

The project is about new applications of a computational imaging technique called ptychography.Ptychography was originally a solution to the phase problem in diffraction patterns. Similar to holography, it can measure the phase of scattered waves as well as just their intensity.However, the method is now seen to have much wider applications in situations where only images can be measured. Other developments mean that it can also cope with what are called 'multiple modes' in an imaging experiment (two unrelated image phenomena occurring in a single data set) such an oscillating 'mixed state'.The method uses variants on the same core inversion algorithm used in 'conventional' ptychography. The specific aims of the project will be to understand the limits of the performance of these algorithms in 'intensity-type' ptychographic inversion. Applications of this generic technique could include improving the resolution performance of astronomical telescopes, a new way of tackling the non-isoplanic blind deconvolution problem, and using its modal properties for message encryption. If calculations are successful, the algorithms will be tested on model data collected on the optical bench.To date, initial worked has centred on a fundamental asymmetry in ptychography. In 'real-space' ptychography, the intensity of diffraction patterns is measured, in 'Fourier ptychography' the intensity of images is measured. Via the principal of reciprocity, both types of data should contain identical information, whereas in fact the quality of the phase and modulus reconstructions in these different modes is very uneven (good quality phase, poor modulus in real-space ptychography, and vice versa for Fourier ptychography). We have determined the reason for this and are now trying to rectify the relevant reconstruction algorithms to overcome this fundamental limitation in the technique.