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Streaming Continuous Optical Nanosecond Events (SCONE)

流式传输连续光学纳秒事件 (SCONE)

基本信息

批准号：
EP/X017842/1
负责人：
Christopher Rowlands
金额：
$ 25.72万
依托单位：
Imperial College London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2023
资助国家：
英国
起止时间：
2023 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FX017842%2F1
关键词：
Streaming Continuous Optical Nanosecond Events

项目摘要

We have always been fascinated by seeing things that are beyond the ordinary - the world that we take for granted every day can inspire wonderment when viewed from a different perspective. This was true when Robert Hooke published Micrographia in 1665; an instant classic, it gave people a view of the microscopic world around them that they otherwise took for granted. In the modern day, high-speed cameras let us see bullets in flight, the movement of electricity in a lightning strike, and the pop of a kernel of popcorn, but there are problems, modern ultrafast cameras are limited in what they can see. Cameras that can take infinite numbers of images of the sample (called streaming cameras) cannot push beyond ~2 million frames per second, whereas 'framing' cameras (which can significantly surpass this limit) can only observe a handful of frames before their capacity is exhausted. Streaming Continuous Optical Nanosecond Events (or SCONE) seeks to increase the imaging speed of streaming cameras by a factor of up to 16, such that they are competitive with framing cameras while still imaging over very long periods of time, to capture rare events and serendipitous occurrences.SCONE works by shining light on the target at different angles. Because the light passes through the sample in more-or-less a straight line, the light can be separated into different paths once it has passed through the sample. Ordinarily this would just provide, say, ten different views of the exact same thing, but if instead we use a very short laser pulse, we can make sure the pulse from each angle arrives at a different time. Now the ten different views observe a different point in time, thus increasing the speed of the camera by a factor of ten.Of course, actually making the pulses arrive at the sample at the right angle and the right time is where the risk and challenge lies. We start from a single laser outputting 200-femtosecond pulses (approximately the time it takes light to travel the width of a human hair) and focus them into an optical fibre. The fibre gets split into sixteen different fibres, each with a sixteenth of the original pulse energy. After splitting, each fibre connects to a different length of fibre which is used to delay the pulse by a certain amount before it comes out the other end. This means that by selecting the length of the fibres correctly, the resulting pulses emerge from the fibre at 57-nanosecond intervals. These can then each be steered towards the sample with a mirror.There are many things this system could be used to look at. Astronomers are interested in the effects of hypervelocity impact on satellites and space stations. New explosives for mining need to be tested to see if they outperform existing materials. Ultrasound waves, travelling at kilometers per second, cause parts of the body to oscillate at tens of megahertz, far faster than any streaming camera can see. It is this last phenomenon we will first address.One of the interesting things about high-powered ultrasound is that it can be combined with tiny injected microbubbles to break down the defences of the brain, known as the Blood-Brain Barrier. This would seem like a bad idea, but because this breakdown is brief and localized, we can use it to introduce drugs to the brain in a way that would normally be impossible. While we know that this breakdown works, we don't know why it works, because we can't see how the bubble moves as it works its way through the Barrier. It is here that SCONE comes into its own. By imaging the bubble at tens of millions of frames per second, for periods of up to a few seconds, we can observe all the unexpected and chaotic behaviour it goes through when exposed to ultrasound. From this we can improve the bubbles, improve the ultrasound parameters, and for the first time, really understand what is going on in this cutting-edge therapy. All of this can only be achieved with SCONE, the world's fastest streaming camera.

我们总是着迷于看到超越平凡的事物-我们每天都认为理所当然的世界可以从不同的角度来看时激发惊奇。罗伯特·胡克（Robert Hooke）在1665年出版《显微摄影》（Micrographia）时就是如此;它立即成为经典，让人们看到了他们周围的微观世界，否则他们认为这是理所当然的。在现代，高速摄像机让我们看到飞行中的子弹，雷击中的电流运动，爆米花的爆裂，但也有问题，现代超高速摄像机只能看到有限的东西。可以拍摄无限数量的样本图像的相机（称为流式相机）不能超过每秒200万帧，而“分帧”相机（可以大大超过这个限制）只能在其容量耗尽之前观察少数帧。流式连续光学纳秒事件（或SCONE）旨在将流式相机的成像速度提高多达16倍，以便在长时间内仍然成像的同时与分幅相机竞争，以捕捉罕见事件和偶然事件。SCONE通过以不同角度照射目标来工作。因为光或多或少以直线穿过样品，所以光一旦穿过样品就可以被分成不同的路径。通常这只能提供，比如说，完全相同的东西的十个不同的视图，但是如果我们使用非常短的激光脉冲，我们可以确保来自每个角度的脉冲在不同的时间到达。现在，十个不同的视图观察不同的时间点，从而将相机的速度提高了十倍。当然，实际上使脉冲以正确的角度和正确的时间到达样品是风险和挑战所在。我们从一个输出200飞秒脉冲的激光器开始（大约是光传播人类头发宽度所需的时间），并将它们聚焦到光纤中。光纤被分成16个不同的光纤，每个光纤具有原始脉冲能量的十六分之一。分裂后，每根光纤连接到不同长度的光纤，用于在脉冲从另一端出来之前将其延迟一定量。这意味着通过正确选择光纤的长度，产生的脉冲以57纳秒的间隔从光纤中出现。然后，这些都可以用镜子转向样品。有很多东西可以用这个系统来看。天文学家对超高速撞击对卫星和空间站的影响很感兴趣。新的采矿炸药需要进行测试，看看它们是否优于现有的材料。超声波以每秒几公里的速度传播，使身体的某些部位以几十兆赫的频率振荡，远远快于任何流式摄像机所能看到的速度。我们首先要解决的是最后一个现象。关于高功率超声波的一个有趣的事情是，它可以与微小的注射微泡相结合，打破大脑的防御，称为血脑屏障。这似乎是一个坏主意，但因为这种分解是短暂的和局部的，我们可以用它来将药物引入大脑，这在正常情况下是不可能的。虽然我们知道这种分解是有效的，但我们不知道它为什么有效，因为我们看不到气泡在穿过屏障时是如何移动的。正是在这里，Scone进入了自己的领域。通过以每秒数千万帧的速度对气泡进行成像，持续长达几秒钟的时间，我们可以观察到它在暴露于超声波时所经历的所有意外和混乱的行为。由此，我们可以改善气泡，改善超声参数，并首次真正了解这种尖端疗法中发生的事情。所有这些都只能通过世界上最快的流媒体摄像机SCONE来实现。