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How many frames per second would you need to film at for a photon of light to be in an identical position on 2 frames?
Speed of light ~300 million km/s. 10 trillion frames per second. Light would have travelled 3cm on each frame.
How many frames per second would you need to film at for a photon of light to be in an identical position on 2 frames?
For 635nm red laser light, you'd need to be sampling somewhere in the order of 9.4 x 10^14 times a second to get two samples per cycle. Based on roughly 300000000m /635nm x2 but then the question comes down to how many cycles make up a photon and does that question even. Make sense in the first place.
Earlier quoted context omitted.
That's incredible. How long did it take to write 0.5s of data to disk? I'm guessing there's no way to sustain this as you'd be so far behind after only a single second. I'm pretty sure we can still only store a few gigs per second. Please correct me if I'm wrong. Very interesting though!
The best way to think of this is it might take 100 seconds to 'record' those 10 trillion frames that occur in 1 second. That doesn't seem to make sense, but imagine this. You want to shoot 100 frames of the first millisecond of an airsoft pellet leaving a gun, but you have a camera that only shoots around 2 frames per second. Your airsoft gun shoots 1 ball exactly (1ns accuracy) every second, exactly the same velocit…
> Using current imaging techniques, measurements taken with ultrashort laser pulses must be repeated many times, which is appropriate for some types of inert samples, but impossible for other more fragile ones.
The new innovation here actually records the frames right after each other of one single event:
> The first time it was used, the ultrafast camera broke new ground by capturing the temporal focusing of a single femtosecond laser pulse in real time (Fig. 2). This process was recorded in 25 frames taken at an interval of 400 femtoseconds and detailed the light pulse’s shape, intensity, and angle of inclination.
How close is this to planck time?
Hijacking this as it’s getting intelligent responses: what’s the greatest resolution we could measure today, and what’s physically possible?
Let's say you have a very bright light source, and that light source results in shining a full 100 Watts of light into the sensor of your camera (I'm using this not as a typical example but because it will make it easy to scale the answer). Photons of visible light have an energy of at minimum 1.5 electron-Volts (800nm red light), which means that 100 Watts of light represents 4.2e20 photons per second.
And that means that with only 100 Watts of light reaching your sensor you cannot attain an fps higher than 4.2e20, because at that speed you'd only get on average around one photon per frame. More realistically you need tens of thousands to millions of photons per frame to have some meaningful level of dynamic range and spatial resolution, which limits the fps to around a quadrillion fps per 100 Watts of light falling on the sensor.
Though once you get into that range you also have problems of signalling, we don't really have electronics that work at those speeds.
Earlier quoted context omitted.
For 635nm red laser light, you'd need to be sampling somewhere in the order of 9.4 x 10^14 times a second to get two samples per cycle. Based on roughly 300000000m /635nm x2 but then the question comes down to how many cycles make up a photon and does that question even. Make sense in the first place.
I apologize for my uninformed question.
Just getting started... o_O
How close is this to planck time?
Hijacking this as it’s getting intelligent responses: what’s the greatest resolution we could measure today, and what’s physically possible?
the signal is extremely weak, the conventional 'shortest-pulse' is around 5 femtoseconds.
[0] https://www.nature.com/news/2010/100728/full/news.2010.381.h...
Earlier quoted context omitted.
Watching this confuses me as to the timing of it all... if the conceit is that we're watching the bundle of photons move through the bottle that's because the photons from the source are hitting the camera, right? So is it the light moving through the bottle + the travel time to the sensor? Should refraction and reflection across the surface cause a lot of weird visual interference (as the bottle's size is no longer…
It kinda is, but as far as i know they're actually taking the multiple photos separately of different pulses and editing them into one video.