Today, we’re at CalTech, because in a building
over there is a camera that absolutely
blows my mind. Now, we’ve filmed
at some very high frame rates. We’re talking up to
about half a million,
which is… – Not to be sniffed at.
– …serious frame rates. Their camera
puts ours to shame and does 10 trillion
frames per second. That’s 13 zeroes. For reference,
that is 20 million times faster than the fastest we’ve
ever filmed on this channel. And there’s not much
you can’t film with half a million
frames a second, but one of those things
is the speed of light. – Not a bad subject.
– No. – Let’s get in there.
– All right. Even the shoe cover
technology is cool. I kind of want one of these
at home, actually. – Just for people.
– All right, let’s go in, see what this CUP
is all about. – Nice to meet you.
– Man: Nice to see you. – How’s it going?
– Good. So, what’s actually– what are we doing here?
This looks all very complicated. Oh, this is the world’s
fastest camera. Oh, okay. Yeah. This is
the world’s fastest camera. There you go.
Just as easy as that. How big is
the actual camera part? I can show you. That big box
is the camera itself. And here is the optics
that we designed – to make the thing work.
– Very cool. A lot of times
in our YouTube comments, we get asked to film
the speed of light. And I have to always
reply to people letting them know
that the speed of light, it’s almost
incomprehensibly fast, and even our cameras,
under a million frames a second, will never see
anything like that. Is this camera capable
of filming the speed of light? Yeah, that’s basically
what we are gonna see. For the example
I’m going to show,
the light will move about the length
of this bottle. In time, how long
does it take for light
to start here and end here? It takes about
2,000 picoseconds. – That’s pretty quick. Yeah.
– Pretty quick. So for the audience,
it goes milliseconds,
microseconds… – Is it nano–
– …nanoseconds, – picoseconds, femtoseconds.
– Yes. So we’re on the sort of
with this stuff. – We’ve never done
that before, for sure.
– Yeah, no. This is completely
on another level. Shall we set up
the first experiment? – Sure, yeah.
– Start with the bottle? – Everyone should wear
– Goggles? – Okay.
– Peng: We have some. – Do I look good?
– You’ve got side panels
in your glasses. – You look like
you’re about to–
– You look bad-ass. It looks like
you’re about to go skiing
with a welding torch. It’s just… So, I assume because
we’re trying to film light, it’ll be useful
to turn all the lights off
in here, right? – Yes.
– Otherwise, we’ll just get… All the ambient
light comes, yeah. Right. Okay. Let’s get ready
for lights off. Yeah. – Can you hold this for me?
– I’ll hold this. – Yeah, thank you.
– I’m excited. I get giddy by this
frame rate stuff. We want to see the light
propagation from the side, so we need to make sure
that the light is scattered
out of the plane of view through the milk
molecules inside, then you can see
light scatter from the side. So, this is a bottle
full of water with
a bit of milk in? So, I am going
to turn on the laser. So all you do is just move
mirrors and lenses around and then it goes
to different areas? We use that to move the laser.
The laser’s too big. See, the light hits
the bottom of the bottle. So it goes through
the bottle. – Is it a powerful laser?
– It’s very powerful. It can basically burn
any, like, papers. – I will stay away from that.
– Yeah. – Whoa, that’s cool.
– You can see its glow. The first thing
I’m going to capture is the static image as our reference. For today,
I’m going to try… – Excellent.
– Yeah, yeah. I mean, I remember
when I was excited when we started shooting, we moved from 1,000
frames a second – to 28,000 frames a second.
– That was a big jump. Okay, we’re pretty much done
with the water bottle. I’d like to take
a photo of this. As you can see,
we can only see the light. We cannot see the bottle
and the label on it. – Yeah.
– So, finally, in the movie,
we may want to overlap both the bottle itself
and the light. – Like, composite
a real picture.
– Yeah, yeah. So you just take a photo
on your phone and that can–
you can do that? Yeah, you can just use
software to overlap
these two things. – Gav: Neat.
– Dan: You’re in
the photograph. Just photo-bombing
the bottle. Okay, let’s watch back
our bottle. This took eight hours
to process, during which time I grew
a slightly longer beard. I had a haircut as well. All right, here we go. Dan:Okay, so what
we’re seeing hereis the bottle’s just been
comped in, basically. Gav:Yeah, this camera only
detects the light itself,which is like
a blue-ish laser light, which is why you don’t
really see anything else other than the light
looking like that. And then we comp in
the picture of the bottle.In the room
with my actual eye,it looked like
it was constantly lit up,but here we’re able to followthe light moving
through the bottle.It may not look like it,
but this is actually real.Dan:It’s refracting the photons
and that’s why you can see it.But when it’s just
going through the air,there’s nothing to actually
reflect the light.Gav:Yeah, it’s only
showing up in the bottle.It is interesting.
It almost looks like sort of
an ’80s film effect.It does, doesn’t it?
It looks like– Like some sort of ghost
flying into the room. But actually, that is light. Gav:Isn’t that weird?
Look at the scale.Every frame seems to be
ten picoseconds.And we’re just
sort of casuallywatching this light
go left to rightthrough the bottle,
but in reality,the light is moving
a million times fasterthan a bullet.– Dan:What a mental subject.
–Yeah.Gav:Okay, so we’ve shot light
through milk.– Next experiment?
– Yep. For this experiment,
we designed a special cavity. We call it a chaotic cavity. When light comes in
the cavity, it will bounce back
and forth multiple times by the mirrors surrounding
in the cavity. – You’re almost
trapping light inside the–
– Yeah. Yeah, exactly. What’s the purpose of this?
This egg thing? This is to create
a water vapor surrounding the environment
so that light scatters out. – The same thing, like–
– Oh, so you can sort of
see a little bit. – Makes sense.
– Yeah, so this is how
the system works. – Turn it on.
– All right, let’s go do
the “experimon.” How long did it take you
to learn to use this? Uh, maybe a few months
to get used– – A few months
to get used to it.
– Yeah. Because it’s a really
complicated system. It’s really complicated,
is it? I hadn’t noticed. ( both muttering ) Okay, so this is
the chaotic cavity at 100 billion frames
a second. Just like nothing. Gav:Once again, the duration
of this video is–you can’t even
get your head aroundhow short an amount
of time it is.Dan:That is amazing.Gav:
When we were in the room,it looked like
the whole thing was glowing,but now we can see
the individual pulse of lightbouncing around this thing.Looks like a weird version
of “Pong.”This is one femtosecond
of laser pulse, so it’s as if
you just went like… – with a laser.
– A femtosecond pulse. Gav:And if you pause it,
you can see it’s just
a dot of light. Dan:And it’s comped in
the shape of the mirrors.I wonder if you could
actually build, like, a big maze
to get it around. Do, like, a little maze
and try to get it in. – World’s fastest
– Yeah. – ( trills )
– Light. Dan:Oh, it almost went in
the corner there.Gav:It is. It’s like the DVD
screensaver, isn’t it?You just want it to go
straight in the corner.Dan:Nearly.– So this one’s 100 billion?
– Yeah. Should we see what
500 billion looks like? – All right, so the area
is quite small.
– Yes. So there’s no way
that we can stand in and be
filmed by this camera. But alternative solution–
little mini-figurines of us. Wait, why is mine–
oh, for goodness sake. – Again, every time.
– So we’ll put them on there. – Flipping heck.
– All right. So, in this experiment,
instead of shooting light
from the side, I’ve changed the beam path
to bounce back this mirror, this mirror,
and use a concave lens to expand the beam
to shoot at an angle. So this is more about
scattering light on the surface
of the figurines? Yes, you’re sweeping across
the surface of the figures. Because we’re obviously
not see-through, so… Yeah. This is the static image
of the two figures. Now I’m doing 500 billion
frames a second with two by two coding. So two by two
and a casual half trill. – ( both laugh )
– Peng: Yeah. I think we’re pretty much
done with this one. This is 500 billion frames
a second of our little figurines,with a resolutionof 549 by 439.The footage is played backat 20 frames a second,therefore it’s slowed down bya factor of 25 billion times.I do like that I was ableto successfully photobomb
this picture.Dan:I like how it shows up
on your nose so much.Gav:All right, I knew
you’d say something about that.It does– it does get caught
by my nose, doesn’t it?– Dan:Yeah.
– Gav:It is interesting
to see the light scatteron the surface of somethingas opposed to go
through our body.Dan:So again,
all they’ve done here
is pretty muchcomp in our bodies
with the light.So the camera would have
got this blue lightand they’ve just taken
a picture and comped in usand matched it up
to where the light hit.Gav:You look miserable
in that.Dan:You look like I’ve just
said something awkward,and you’re like, “Ooh.” – Should we do these poses?
– Yeah, sure. Gav:And you can see
on the time scaleit’s a much slower progression
of picoseconds.as opposed to half a trillion
frames a second.All right,
that’s 500 billion done. – Child’s play.
– Child’s play. – Let’s crank it up.
– All the way? – Yep.
– All right. Let’s do 10 trillion
frames a second. So, Peng, we’re at
a different camera now. – Is that correct?
– Yeah. And this one can do
up to 10 trillion frames
a second? Yeah, yeah.
This is the 10 trillion
frames a second. That’s the maximum speed
that we can do. Here we have a sample
which contains diluted milk, about a few millimeters long. That’s all that
the camera’s looking at,
is a few millimeters long? Yeah, that’s how long
the light propagates
within 30 picoseconds. Dan: Okay, wow. Here is the same software that we use to
capture the image. So for this one
we’re allowed to keep
the lights on? Because we are doing
ultra fast images within
a very narrow time scale there’s a minimum amount
of light that comes
through the ambient light. – In comparison
to the powerful laser.
– Laser, yeah. – It’s all relative, I suppose.
– Yeah, much brighter. – All right, cool.
– Yeah, this is how it works. Dan: So this is
a much smaller scale ’cause we’re using
a higher frame rate capturing a very much
smaller amount of space and time,
essentially. – Yes.
– Gav: All right. This is the light traveling
through the milk vial at 10 trillion frames
a second. – This is the reason
we came here.
– Yeah. – Gav:So cool.
–So on the bottle video,the light seemed to have
gained the same speed.But then you gotta remember
that the scale of thisis much smaller.
So this is one millimeter,it says here,
is the distance,whereas before,
it was an entire bottle.Which shows you that
we’re actually recordinglight traveling through
such a small amount of space.Gav:And it’s so slow now
that our picosecondhas a decimal place to
the hundredth femtosecond.Dan:That’s blowing my mind
for a start.Gav:When Peng turned on
the laser,I didn’t see anything at all.But now we can actually
see how it moves.On this scale of time,if we fired a bullet
through this frame,it would take yearsto go from one side
to the other.Dan:And the light
is just going, blip.That really puts it
into perspective as well,
doesn’t it?I just feel like no human
should ever have seen this. It’s like looking at
the base of the universe.I’ve heard
that in the future,the CalTech team actually
intends to increase the speedup to one quadrillion
frames per second.It’s a bit mind-blowing,
to be honest. Gav: We have to leave now
and go back to our old measly hundreds of thousands
of frames a second. Measly, pathetic
hundreds of thousands. Thank you very much, Peng,
for showing us your amazing kit. – Thank you.
– Yeah, thanks. – Thank you.
– Learned a lot. Yeah. Well, to me,
that’s some of the most mind-blowing footage ever. I mean, visually,
it’s just a blobgoing from left to right.But to know that
that’s light–Dan:I would say it
was actually one of the mostmind-blowing things
that we’ve seen.Well, I feel
very accomplished. Hopefully,
you enjoyed watching light move through the air
in slow-mo. Feel free to check out
other episodes from “Planet Slow Mo,”
and join us in part two, where we’ll be
learning a lot more about how this camera works. You can subscribe, too,
if you want. We’d appreciate it. Still not sure
I’ll be able to understand
it after part two. – We’ll do our best.
– All right.