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Ultra-high-speed imaging is widely used in material characterization, biochemistry, time resolved spectroscopy, fluorescence lifetime imaging, Photoluminescence, Diffuse optical tomography, etc. The very fastest cameras are based on a vacuum tube technology such as the streak tube, image intensifier or photomultiplier and can achieve the best temporal resolution in direct light detection devices. For instance, a time gated camera operation with an image intensifier tube is able to sample a scene with a spatial resolution of 1000x1000 pixels with a gate of 1 ns, leading to a pixel rate of 1.1015 pixels per second, i.e., one petapixels/s. In order to manage this tremendous pixel rate, the acquired images are temporally stored on a phosphorous screen and are readout with a classical camera at a conventional pixel rate. This approach is known as the burst imaging concept that consists to let image in the sensor during the acquisition and readout the images afterward. Thus, an intensified gated camera is able to record only one image of a single fast event, but by using several cameras acquiring the same scene through a light splitter a movie of can be recorder with a temporal resolution of 1 ns. In order to push further the temporal resolution, the concept of streak imaging can be used. It consists to reduce the spatial information to a single line of pixels instead of a full frame in order to enhance the temporal resolution. The history of high-speed imaging shows that this approach can improve the temporal resolution by a factor 100 to 1000. For instance, a streak camera also operating with a vacuum tube device can still sample one petapixel/s but offers a temporal resolution of 1 picosecond with the reduced spatial resolution of 1x1000pixels. The drawbacks of this technology are that the vacuum tube-based cameras are bulky, fragile and expensive. It’s the reason why many works are ongoing on the design of some specific solid state sensors for high-speed imaging. The conventional CMOS or CCD sensors are limited by the extraction speed of the image to a pixel rate of a few Gigapixel per second. On the contrary, the systems storing the video frames inside the sensor are not limited by the readout speed and the so-called burst image sensors (BIS) achieve a pixel rate of more than 1 Terapixel per second. The video BIS at the state-of-the-art can sample and store about 100 frames of a 2D scene with a frame rate of more than one Mega frames per second (fps) up to 100 Mega fps by using on-chip analog or digital memory. The latest achievements in ultra-high-speed CMOS image sensors using the streak imaging concept push the line rate up to several giga fps and offer a sub nanosecond temporal resolution. Moreover, these innovative sensors add some new features such as the post trigger acquisition unrealizable with the vacuum tube-based cameras.
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