High speed, ultra-low photon flux imaging

成像系统的发展历来集中在光学和相机技术的设计上。电子探测器已经取得了重大进展，包括紧凑的硅像素阵列和小形状因子透镜，使可见光相机便宜，高分辨率和大规模生产。这些设备还支持生物医学和远程成像的进步，其中更大的像素密度和分辨率一直是主要目标。未来的系统需要的性能远远超出简单的图像捕获。精确的定时信息提供了对3D成像技术的访问，而智能图像处理和空间可调光学器件可以产生亚衍射极限图像。在少数光子限制下的相机操作可以利用相关效应，超越经典限制并提供安全性。为了实现这些成像应用，光源必须与探测器技术并行考虑。在光子学研究所，我们一直在开发具有卓越性能参数的micro-LED显示技术。每个像素的直径只有几微米，可以以100 MHz的速率切换，脉冲宽度为纳秒。这些像素的阵列直接键合到CMOS驱动电子器件上，从而对其时空输出提供前所未有的控制。空间结构光场提供了一种全新的照明形式，已在可见光通信和室内导航中显示出应用。该项目将进一步开发时空照明源的潜力，目标是在单光子范围内的超低光水平下运行。通过使用单光子雪崩探测器（SPAD）阵列，我们将能够在空间和时间上创建生成和探测光子的相关性。这种能力将允许用极少量的光子捕获图像，并结合稀疏图像处理技术。这些成像系统的应用包括低通量生物系统，水下数据通信和导航，以及量子成像和机器人控制。博士生将有机会使用最先进的LED和SPAD阵列来创建下一代成像系统。他们将开发用于低通量成像和导航的时空调制和解码方案，并使用定制电子设备实现这些方案。该系统将在宏观和微观尺度的成像应用中进行演示。

The development of imaging systems has historically been focussed on the design of optics and camera technologies. Major advances have been made in electronic detectors, including compact silicon pixel arrays, and small form-factor lenses, making visible light cameras cheap, high resolution and mass producible. These devices also underpin advances in bio-medical and remote imaging where greater pixel density and therefore resolution has been the major goal. Future systems require performance that goes well beyond simple image capture. Accurate timing information provides access to 3D imaging techniques, while smart image processing and spatially tunable optics can produce sub-diffraction limited images. Operation of cameras in the few photon limit can make use of correlation effects, beating classical limits and offering security. To enable these kinds of imaging applications optical sources must be considered in parallel with the detector technologies.At the Institute of Photonics we have been developing micro-LED display technologies with remarkable performance parameters. Each pixel is only a few microns in diameter and can be switched at 100's of MHz rates, with pulse widths of nanosecond duration. Arrays of these pixels are bonded directly onto CMOS drive electronics providing unprecedented control over their spatio-temporal output. The spatially structured light-field gives access to an entirely new form of illumination that has shown application in visible light communications and indoor navigation. This project will develop the potential of spatio-temporal illumination sources further, targeting their operation at ultra-low light levels in the single photon range. By using Single Photon Avalanche Detector (SPAD) arrays, we will be able to create correlations of generated and detected photons in both space and time. This ability will allow the capture of images with extremely few photons, combined with sparse image processing techniques. The applications of these imaging systems include low flux biological systems, underwater data communications and navigation, and quantum imaging and robotic control.The PhD student will have access to state-of-the-art LED and SPAD arrays with which to create next generation imaging systems. They will develop spatio-temporal modulation and decoding schemes for low flux imaging and navigation, implementing these using custom electronics. The systems will be demonstrated in macro and micro-scale imaging applications.