How high-speed a camera would be needed to capture the movement of photons?

Let me tell you the answer first. On April 19, 2020, Chinese scientists captured the trajectory of photons with a high-speed camera, which is about 4 trillion frames per second. I still have to boast that China's scientific research capabilities are constantly improving, and I also have to thank those scientific researchers for their hard work. After all, photographing photon trajectories is really not a thing. You must know that the speed of light propagating in a vacuum is 299,792,458 meters per second. This is the limit of movement of all stationary mass objects in the universe. No matter can exceed this limit. You must know that the speed of photons is so fast that catching up with it is something scientists particularly want to do. Now the dream has come true.

First of all, you need to understand the working principle of the camera. The camera can record the image through film or sensor by receiving the reflection from the object being photographed. That can be said about the difficulty of photon photography. Generally speaking, the objects to be photographed must be able to reflect light or refract light. You must know that light is an electromagnetic wave. Light does not have the characteristic of reflected light. After two beams of light meet, they will only pass through each other. Therefore, it is really not a simple matter to capture an image of Guangde through a camera. In addition, photons are the smallest unit in light propagation. The camera can only record the activity of photons for a moment, and there is no way to record the continuous movement of photons.

Chinese scientists actually used a compressed sampling technology to overcome this difficulty, allowing the image to be preserved through the CCD overlapping area. The great thing about this technology is that the camera can take a picture in 260 femtoseconds, and then use technical means to overlap the continuous recording moments, so that the trajectory of the photon movement can be captured.

This technical overcoming is really a milestone in the scientific community. I would like to thank the researchers again for their persistence and hard work. Because of you, we see the trajectory of photons.