Spheres are easy; controlling the exact size might be tricky, but you can just make a lot and then sort them. The lens might be harder, depending on size and shape.
What kinda fascinates me is how simple (on paper) this idea is, despite it's originality. It doesn't require much knowledge on the specifics to understand it, as it's literally just refraction and conservation of momentum and I'm fairly sure even a high schooler could understand the processes involved
the true is , it is difficult once you really understand what did they do. He just put it on lame terms for the average high school student to understand , but this is HARD to do.
After watching this I thought: Wow! Both of these actually Nobel-worthy ideas are so simple, yet so well explained here, that it makes one feel like any old layman could have come up with them and grabbed that prize... But of course "Understood instantly" does not mean "Able to invent". Question: How well does the glass ball suspended in a beam of light handle movement of said beam? Rotation, withdrawal, acceleration, etc. Say; If I point my laser slowly away from it, will the glass ball follow along? And what is the speed limit here? Rate of change; can it be high? As fast as light speed, perhaps? Or a non-epsilon magnitude / medium-sized fraction of it? Example: A sudden 180° will likely drop or launch the ball, losing it; but a subtle focal length adjustment or a nanometer push/pull will not. The subject will be re-centered by the various forces as shown in the animation.
Let's do a ballpark estimate. The limiting factor is how much acceleration can the beam put into the ball. The ball has known mass (m) and the laser has known power (P). Movement perpendicular to the beam is stabilized by the refraction. Let's assume the ball is perfectly transparent and that there is a position where it refracts the full beam perpendicularly. The acceleration of the ball is a=F/m. The force provided by the beam is its power divided by speed of light F=P/c. So the maximum theoretical acceleration of the ball is a ~ P/(c*m). Off course in practice it will be less. We need to take into account absorption, the fact that the refracted beam is divergent, the fact that horizontal refraction may not be possible etc. All of these are some factor ~0.001. We now may substitute some numbers. Wavelength of the laser is l~10^-6m. Volume of the ball is V=l^3=10^-18m^3. Density of glass is ro~1000kg/m^3, so the mass of the ball is m=ro*V~10^-15kg. The power of the laser is P~1W. Speed of light is c~10^8m/s. The acceleration is a~0.001*P/(c*m) ~ 10^4m/s^2 ~ 1000g. I probably underestimated the size of the ball significantly. But nevertheless, the force seems to be strong enough that you can probably walk around with the suspended ball, but probably not enough to shoot it out of a cannon.
I would imagine that it wouldn't have a hard speed limit, but rather a point where it's accelerating so slowly it's basically not accelerating at all anymore (then a practicality limit where the laser will refract over a long enough distance). The closer it gets to the speed of light, the more energy it's going to need to accelerate. At some point this will mean that the tiny force being exerted is still technically speeding it up, but not really in any measurable way. Objects with mass cannot reach the speed of light because the energy requirement to speed it up approaches infinity as you get closer it. Might start out kind of fast though, the fact that they can hover it means it's counteracting it's natural 9.8m/s acceleration towards Earth.
I got some pretty amazing mathy replies. Thanks guys! I really appreciate the free education you've given me this day. + Make sure you click "Show more replies" and "Read more" on each of them, to learn like I did. Especially comments by Victor Titov, KohuGaly, and psmitty840. Huge thumbs up to you all.
@@x3ICEx it should track the beam if done slow enough, but you gotta look at the scale, tiny glass beads might be finicky if you moved em by hand. tiiny adjustments, not so much movements
I'm curious what the limit is for the amount of mass you could push with a laser and how much power you would need to move large masses. This reminds me of the classic tractor beam where you have a beam of light that holds a spaceship in place and can even pull them closer.
I was invited to Gerard Mourou's lab once about 15 years ago. It was quite impressive. I got out of the laser business to do robotics, but it was a lot of fun back then.
I would love a series of videos in which each professor explains his specific field of research and his current work, I think would be really interesting.
Amazing stuff and it's great that students are being rewarded as well. It's got to sting a bit for past students having been over-shadowed because it's hard to parse thoughts and effort during semi-collaborative PhD level research.
@@PolemicContrarian 1)laser can reflect from ground might work 2)Cow have gravitational pull so if you will light not cow, but area around it then light should be get bend by gravity of the cow. So now it move under some angle, which means it lost some of its downwards momentum. And by laws of conservation cow should be accelerated up. P.S.: i know that you just can't make this powerfull laser without destroying half a universe, but whatever
@@ronaldderooij1774 Don´t be. The guys who invented the transistor famously did not depriving IBM from controlling the world and PhDs are often considered public.
I remember seeing this in the local paper. Bell Labs in Holmdel NJ. The really old guy was once a high school teacher in Holmdel High School. Bell Labs, Holmdel no longer exists and was abandoned a while but now is in a revival as a telecom research and business office building with housing around it. If you want to read about it, look up Arthur Ashkin in the Asbury Park Press. When Bell Labs shut down, many of the employees became teachers and professors in our area. Many of my science teachers who are older worked there when I was in HS.
I love that these nobel prizes, especially the first one, are easy enough to be understood by high school students! Props to the winners and thanks prof for the explanation :)
9:36 I know that sine waves are the building blocks of a fourier transform, and that a perfect single sine wave goes on to infinity. However, as everyone likes to quote, you can add up numerous (infinite) sine waves to generate a tighter and tighter pulse. My question is, how do you add up infinitely repeating sine waves to generate a pulse located about a single point. I do understand how waves come together to make square waves, and triangular waves, and any other repeating structure, but how can it possibly make just a single point that never repeats all the way to infinity? I guess, another way that I could explain my question is, what waves of the form 'A+Bsin(C+Dx)' do you need to add to the simple sine wave 'sin(x)' that starts you on the journey to a single, discrete pulse?
Noble prize!!!!!!!!!!!! I always believed that understanding this would be not my piece of cake but this video is an eye-opener. The best-simplified explanation that I ever came across.
I apologize - haven’t read the paper but I’ve got a hypothesis RE the question about momentum transfer: Refraction occurs due to molecular transformations in the glass altering the electric field part-way constituting the photon (collectively summarized by dielectric constant of glass). This deformation suffices to explain momentum transfer. Brilliant brilliant work to all scientists and grad students on this project.
Glad to see you bring out that an interference pattern was needed to create the short burst, but does the initial laser pulse naturally develop the best frequencies to create this interference pattern?
I really really like this video and the simplicity of your way of explaining it. It is a must-watch video I will share with my students in my course! Thanks.
This is mindboggling, because in the same object (this ball) light behaves both as a wave and a particle. Makes me realize how little we understand what the universe is, and the great lengths we went to try to understand them.
Ok for the conservation of momemtum, but what about the conservation of energy ? If momemtum (energy)is given to the sphere then what happens to the light that passes through the sphere ? How did it lose energy ? Did the wavelength change ?
Wavelength increases. However, because the bead is so much heavier than the photon, very little energy is transfered. Imagine the photon is a small ball and the bead is a boulder: when the ball hits the boulder it bounces off with the same speed and same energy, however it did transfer double its momentum to the boulder because it changed direction.
There is no solid that can be 100% clear to a wavelength of light, therefore it will absorb some of the electromagnetic energy as it passes through. Since light has momentum, and that must be preserved, the glass bead will gain a net increase in momentum away from the light source, and grow warmer as it absorbs energy. The scientists simply used clever lenses to adjust the angle of the net momentum gain of the bead to work in their favor.
@5:02, does this remind anyone of Tsuna from katekyo hitman reborn, when he learns to balance himself while shooting a hard and focused flame in front, while supporting himself with a soft wide flame backwards?
Someone in an earlier comment names this speaker as Prof. Merrifield, Thank You, Prof Merrifield, for explaining this so well. Very interesting. Love & Peace to All
For the optical tweezers, why not just shine another laser beam shining in the opposite direction? So it would also provide the same push toward the center of the beam (call it up and down) but oppose the first lazer (call that left and right.) There must be a n obvious answer, but I don't see it.
If you need to use in any practical applications, eg medically, it would be hard if not impossible to get light from the direction of the body, wouldn't it? So a solution would then have to be found anyway.
I assume it just would be tricky to balance to amplitudes of both beams so that you cancel the drift effect. The brilliance of the lens solution is that its a self correcting solution - a small drift in one direction makes for a stronger counter force to fix it. In the case of two opposite lasers, if they aren't perfectly balanced (which is hard to do) you won't get the self correction feature.
Also, if nothing else, it would be tremendously fiddly getting the laser beams aligned right, especially if the beads you are talking about are microscopic (which they generally are).
Probably the same problem as trying to balance gravity by pointing the beam upwards (i.e., hard to get it perfectly balanced, you end up with a drift). With two beams you'd have to line them up perfectly _and_ balance their intensities perfectly. This system is self-balancing.
At 1:40, when you talk about the size(or diameter) of the sphere being equal to wavelength of light, which part of the spectrum are you actually referring to?
I was using optical tweezers back in college. It was used to turn and rotate cells. I was also using electricity standing waves to do the same thing. But these lasers were more troublesome than the electricity method. So just replace the glass bead with a human cell and that is what I was doing.
All scientific researches are published for everyone to read. For the technical aspects and the full explanation of the processes described above, you need to search for the original papers submitted by the authors. On the second case though, the research said it was done while Dr.Strickland was a Ph.D. student so expect a > 100-page read.
When you run water over a boiled egg in the bottom of a pot, I've noticed the egg will tend to roll itself into the stream, ending up basically centered under the water. I only noticed this recently, and found it really funny that it wasn't something I'd heard about growing up as, like, some pop science tidbit from Bill Nye or something. Maybe it's common knowledge, and I just missed that episode...
It's similar to how a strong stream of air can capture a capture a round object. If the fluid hits the round object off center, it will follow the curve and pull the object towards the center of the stream (the result is even stronger if the object can spin) I think some demos were done with a ping-pong ball and a hair dryer
Just out of intrigue, isn't the principal of levitation mentioned in the video very much similar to acoustic levitation. But I know for sure that in acoustic levitation you need nodes of interference from different frequencies to levitate things can't see how that happens for a laser.
The 'tweezer' seems to have a venturi effect, around the sphere, (or maybe inverse venturi), and the sphere looks to have a positive bouyancy in the beam. I may be reading too much into it.
This seems like an optical version of floating a ping-pong ball in the middle of a stream of flowing air. The ball is stable within the beam precisely because, if it happens to wander off-center for a moment, it deflects the air flow in just the right direction that the recoil pushes it back towards the center. There are also some experiments on "sound levitation" on RUclips that perhaps are an acoustic analog of the optical tweezers.
that is so cool .. darn! in those moments i seriously love physics! if you want to get more people into stem .. show them such hands on, brilliant solutions for physical problems.
Is it possible to measure gravitational waves using this very sensitive apparatus? (incidentally, LIGO also uses light but a very different property of light)
Wait, but if there is some mechanical process of the photons which get refracted hitting the sphere, mustn't the photons lose just a little momentum so they aren't moving at lightspeed anymore or am I missing something?
What if, instead of the recombiner, they put a mirror, so light gets amplified again, and the "light splitter gizmo" works as recombiner, too? (if it's optical like in the drawing)
While watching another Sixty Symbols video (Feynman Diagrams) I followed up a passing reference to a guy called Stueckelberg. Now I'd like to suggest a video about Baron Ernst Carl Gerlach Stueckelberg von Breidenbach zu Breidenstein und Melsbach, to give him his full name. Quoting from Wikipedia: "Stueckelberg developed the vector boson exchange model as the theoretical explanation of the strong nuclear force in 1935. Discussions with Pauli led Stueckelberg to drop the idea, however. It was rediscovered by Hideki Yukawa, who won a Nobel Prize for his work in 1949 - *the first of several Nobel Prizes awarded for work which Stueckelberg contributed to, without recognition* ".
I have a few newbie questions. Why does the glass/ plastic sphere stay in place in the laser beam? Although the gaussian beam is brightest in the middle is the gradient the same downwards and upwards? if so why is the particle displaced slightly up and not down. force of gravity acting on it should keep it displaced slightly down in my newbie mind.
I gave a round of clapping in real life for the genious the not-moving-back-and-forth method was for the laser tweezer. That's really freaking genious.
I find it so hard to fathom how physicists can use single particles and molecules in their experiments and measurements. Maybe you could do a video explaining it!
Why is the light scattered in that pattern after entering the glass bead from being focused from the microscope lens? And why does it diverge from that specific point within the bead? Cheers.
I wonder if this kind of technology if scaled up can be used to help with a space elevator 'car'. Using lasers strong enough to beam straight upwards. It may be more economically or environmentally efficient/friendly.
i didn't understand, how the lens is manipulating momentum, i mean the mass of light refracting from the other side is same as that hitting the sphere, how can area of light emerging , change the momentum?
Fascinating. So presumably by measuring the movement of the sphere in the beam researchers should be able to design gravitometers to measure micro changes in gravity. If this is the case I assume that with sufficient resolution you would be able to measure inhomogeneities under the earth surface. Say waterpipes or mine shafts?
More physics Nobel Prize videos: bit.ly/SSNobel
The 2018 Nobel Prize in chemistry: ruclips.net/video/fMKtFKphuds/видео.html
Lazer tweezers are Amazingk, just dont install them on Cats! \o7
5 mins? I'd listen to Dr. Merrifield talk for hours!
Sixty Symbols i would place a strong neodymium magnet near it to see if you can move it out of the light beam? 🤔🧲 🤷♂️
+Sixty Symbols
Do more nobel prizes please :D
This is so nice!! Keeps me up to date with new and important physics ideas quick and easy. Love it!
great animation and wonderful discussion -- thank you for sharing
"Alright, he can keep his Nobel Prize"
You're too kind.
That part was funny!
Ohh it was his comment not your , i was going to comment ( that - Are you jealous ) you before knowing that 😃😄
11:32 later he said " i can win the Noble prize "
*Making* such tiny spheres and lens is what impresses me the most...
Your lens could be bigger than that and the transistors in your phone are way smaller than this sphere so it is possible. But yes very impressive
Spheres are easy; controlling the exact size might be tricky, but you can just make a lot and then sort them. The lens might be harder, depending on size and shape.
this two can have great implication... in weapon industry i can imagine...so lets destroy ourselves:)
also that they can attach one end of DNA to that lens
You can buy them off the Internet for cheap. We used them for human cell dummies. Lot more sanetary and prepared use fit the real thing.
Dude, Donna strictland was my electromagnetism prof last year.
Which uni?
@@-_-8229 U Waterloo (Canada)
@@raintrain9921 oh cool.
Thank mr goose.
I'm in physics at u waterloo as well my man
What kinda fascinates me is how simple (on paper) this idea is, despite it's originality. It doesn't require much knowledge on the specifics to understand it, as it's literally just refraction and conservation of momentum and I'm fairly sure even a high schooler could understand the processes involved
12:04
Until you do the engineering part ...
the true is , it is difficult once you really understand what did they do. He just put it on lame terms for the average high school student to understand , but this is HARD to do.
@@The4stro same, have never taken physics, but the idea is so simple it is easy to understand
Engineering is where the real applications begin. And horrors to unveil.
I love your interactions with all people you make videos with. It seems like you have bonded over the years.
"...so simple and because of that so elegant..."
exactly the point of great science
As a young Australian aspiring to be a filmmaker, all of Brady's videos are very inspiring. Keep up the great work!
After watching this I thought: Wow! Both of these actually Nobel-worthy ideas are so simple, yet so well explained here, that it makes one feel like any old layman could have come up with them and grabbed that prize... But of course "Understood instantly" does not mean "Able to invent". Question: How well does the glass ball suspended in a beam of light handle movement of said beam? Rotation, withdrawal, acceleration, etc. Say; If I point my laser slowly away from it, will the glass ball follow along? And what is the speed limit here? Rate of change; can it be high? As fast as light speed, perhaps? Or a non-epsilon magnitude / medium-sized fraction of it? Example: A sudden 180° will likely drop or launch the ball, losing it; but a subtle focal length adjustment or a nanometer push/pull will not. The subject will be re-centered by the various forces as shown in the animation.
Let's do a ballpark estimate. The limiting factor is how much acceleration can the beam put into the ball. The ball has known mass (m) and the laser has known power (P). Movement perpendicular to the beam is stabilized by the refraction. Let's assume the ball is perfectly transparent and that there is a position where it refracts the full beam perpendicularly. The acceleration of the ball is a=F/m. The force provided by the beam is its power divided by speed of light F=P/c. So the maximum theoretical acceleration of the ball is a ~ P/(c*m).
Off course in practice it will be less. We need to take into account absorption, the fact that the refracted beam is divergent, the fact that horizontal refraction may not be possible etc. All of these are some factor ~0.001.
We now may substitute some numbers. Wavelength of the laser is l~10^-6m. Volume of the ball is V=l^3=10^-18m^3. Density of glass is ro~1000kg/m^3, so the mass of the ball is m=ro*V~10^-15kg. The power of the laser is P~1W. Speed of light is c~10^8m/s. The acceleration is a~0.001*P/(c*m) ~ 10^4m/s^2 ~ 1000g.
I probably underestimated the size of the ball significantly. But nevertheless, the force seems to be strong enough that you can probably walk around with the suspended ball, but probably not enough to shoot it out of a cannon.
I would imagine that it wouldn't have a hard speed limit, but rather a point where it's accelerating so slowly it's basically not accelerating at all anymore (then a practicality limit where the laser will refract over a long enough distance). The closer it gets to the speed of light, the more energy it's going to need to accelerate. At some point this will mean that the tiny force being exerted is still technically speeding it up, but not really in any measurable way. Objects with mass cannot reach the speed of light because the energy requirement to speed it up approaches infinity as you get closer it. Might start out kind of fast though, the fact that they can hover it means it's counteracting it's natural 9.8m/s acceleration towards Earth.
I got some pretty amazing mathy replies. Thanks guys! I really appreciate the free education you've given me this day. + Make sure you click "Show more replies" and "Read more" on each of them, to learn like I did. Especially comments by Victor Titov, KohuGaly, and psmitty840. Huge thumbs up to you all.
@@x3ICEx it should track the beam if done slow enough, but you gotta look at the scale, tiny glass beads might be finicky if you moved em by hand. tiiny adjustments, not so much movements
I'm curious what the limit is for the amount of mass you could push with a laser and how much power you would need to move large masses. This reminds me of the classic tractor beam where you have a beam of light that holds a spaceship in place and can even pull them closer.
2:47 that auto correction method reminded me with the belt on crowned pulleys correction mechanism in a mechanical system.
Also similar to railway tracks.
These videos are the most inspiring thing in my life.
I feel sorry for you.
Brady was pretty challenging this time! I commend Michael Merrifield for his patience.
I love his questions tho. They teach me a lot as well.
I was invited to Gerard Mourou's lab once about 15 years ago. It was quite impressive. I got out of the laser business to do robotics, but it was a lot of fun back then.
Ok?
Yes, there is great ingenuity in making extraordinary material advancements starting from the obvious approach.
I would love a series of videos in which each professor explains his specific field of research and his current work, I think would be really interesting.
The invention of Laser tweezer is a great idea. Deserves the Nobel prize. Congratulations.
can't help but notice prof Merrifield changing with time. Been watching this channel from the start,basically growing up with these people.
With all the infotainment rubbish on youtube, its a pleasure to see some gem quality offerings. Thank you!!!!
How do you glue a molecule?
In soviet russia molecules glue YOU
Maybe with static electricity
Airfix cement
Flex tape
Elmer’s
It’s probably some kind of chemical bond
Amazing stuff and it's great that students are being rewarded as well. It's got to sting a bit for past students having been over-shadowed because it's hard to parse thoughts and effort during semi-collaborative PhD level research.
The UFO lightcone in cartoons, picking up cows must work this way!
If the cow is round enough and doesn't get toasted on the way up...
Well, maybe they're just looking for some delicious earthly beef.
No, as both gravity and the force of the laser are pushing them down - the opposite direction.
@@PolemicContrarian 1)laser can reflect from ground might work
2)Cow have gravitational pull so if you will light not cow, but area around it then light should be get bend by gravity of the cow. So now it move under some angle, which means it lost some of its downwards momentum. And by laws of conservation cow should be accelerated up.
P.S.: i know that you just can't make this powerfull laser without destroying half a universe, but whatever
This second NP looks so much like a patentable invention rather than a discovery.
Yes, and I think it was patented. I would be amazed if it wasn't.
@@ronaldderooij1774 Don´t be. The guys who invented the transistor famously did not depriving IBM from controlling the world and PhDs are often considered public.
@@ronaldderooij1774 it is not patended. you can build your own cpa laser system and sell it.
I love how elegant and simple the amplifier is.
This channel is so amazing, makes me feel like I'm still in touch with physics
It's like how the Bernoulli effect holds a ball in a airstream. Only with light.
and without the air passing through the ball...
nah not quite
Exactly like that! Nicely done.
Darik Datta exactly what I though, I use to levitate a pingpongball with a hairdryer when I was little kid
He was right, y'know. Each of these two concepts took on average about five minutes to explain.
I remember seeing this in the local paper. Bell Labs in Holmdel NJ. The really old guy was once a high school teacher in Holmdel High School. Bell Labs, Holmdel no longer exists and was abandoned a while but now is in a revival as a telecom research and business office building with housing around it. If you want to read about it, look up Arthur Ashkin in the Asbury Park Press. When Bell Labs shut down, many of the employees became teachers and professors in our area. Many of my science teachers who are older worked there when I was in HS.
I love that these nobel prizes, especially the first one, are easy enough to be understood by high school students! Props to the winners and thanks prof for the explanation :)
9:36
I know that sine waves are the building blocks of a fourier transform, and that a perfect single sine wave goes on to infinity. However, as everyone likes to quote, you can add up numerous (infinite) sine waves to generate a tighter and tighter pulse. My question is, how do you add up infinitely repeating sine waves to generate a pulse located about a single point. I do understand how waves come together to make square waves, and triangular waves, and any other repeating structure, but how can it possibly make just a single point that never repeats all the way to infinity?
I guess, another way that I could explain my question is, what waves of the form 'A+Bsin(C+Dx)' do you need to add to the simple sine wave 'sin(x)' that starts you on the journey to a single, discrete pulse?
My faculty advisor is a Biophysicist and was excited when this Nobel Prize was announced!
Noble prize!!!!!!!!!!!! I always believed that understanding this would be not my piece of cake but this video is an eye-opener. The best-simplified explanation that I ever came across.
wow, a teacher that can actually teach. Prof Merrifield is great at distilling the concept down to an approachable morsel.
I apologize - haven’t read the paper but I’ve got a hypothesis RE the question about momentum transfer: Refraction occurs due to molecular transformations in the glass altering the electric field part-way constituting the photon (collectively summarized by dielectric constant of glass). This deformation suffices to explain momentum transfer.
Brilliant brilliant work to all scientists and grad students on this project.
This is such an amazing channel. Complex ideas explained in a way that anyone can understand. Thank you for all the amazing work.
Glad to see you bring out that an interference pattern was needed to create the short burst, but does the initial laser pulse naturally develop the best frequencies to create this interference pattern?
I really really like this video and the simplicity of your way of explaining it. It is a must-watch video I will share with my students in my course! Thanks.
This is mindboggling, because in the same object (this ball) light behaves both as a wave and a particle. Makes me realize how little we understand what the universe is, and the great lengths we went to try to understand them.
I have to give a presentation on this in a week, and the explanation here is incredibly helpful. Thanks so much!
the phrase in 2:45 why??? shouldnt the particle be pushed in the same direction as where the light is pushing him ??
Ok for the conservation of momemtum, but what about the conservation of energy ? If momemtum (energy)is given to the sphere then what happens to the light that passes through the sphere ? How did it lose energy ? Did the wavelength change ?
Most likely the bead was heated up slightly.
Wavelength increases. However, because the bead is so much heavier than the photon, very little energy is transfered. Imagine the photon is a small ball and the bead is a boulder: when the ball hits the boulder it bounces off with the same speed and same energy, however it did transfer double its momentum to the boulder because it changed direction.
There is no solid that can be 100% clear to a wavelength of light, therefore it will absorb some of the electromagnetic energy as it passes through. Since light has momentum, and that must be preserved, the glass bead will gain a net increase in momentum away from the light source, and grow warmer as it absorbs energy. The scientists simply used clever lenses to adjust the angle of the net momentum gain of the bead to work in their favor.
@5:02, does this remind anyone of Tsuna from katekyo hitman reborn, when he learns to balance himself while shooting a hard and focused flame in front, while supporting himself with a soft wide flame backwards?
Rudolf Mössbauer also got his Nobel prize for his PhD thesis work, actually receiving it 3 years after his defence. And that was back in 1961.
Best channel to underdstand every year's nobel prize
Someone in an earlier comment names this speaker as Prof. Merrifield, Thank You, Prof Merrifield, for explaining this so well. Very interesting. Love & Peace to All
For the optical tweezers, why not just shine another laser beam shining in the opposite direction? So it would also provide the same push toward the center of the beam (call it up and down) but oppose the first lazer (call that left and right.) There must be a n obvious answer, but I don't see it.
If you need to use in any practical applications, eg medically, it would be hard if not impossible to get light from the direction of the body, wouldn't it? So a solution would then have to be found anyway.
I assume it just would be tricky to balance to amplitudes of both beams so that you cancel the drift effect. The brilliance of the lens solution is that its a self correcting solution - a small drift in one direction makes for a stronger counter force to fix it. In the case of two opposite lasers, if they aren't perfectly balanced (which is hard to do) you won't get the self correction feature.
Also, if nothing else, it would be tremendously fiddly getting the laser beams aligned right, especially if the beads you are talking about are microscopic (which they generally are).
Probably the same problem as trying to balance gravity by pointing the beam upwards (i.e., hard to get it perfectly balanced, you end up with a drift). With two beams you'd have to line them up perfectly _and_ balance their intensities perfectly. This system is self-balancing.
You also get the problem that whatever machine is creating your laser beam is now having a laser beams fired directly at it.
It's not only a pair of tweezers it's also a scale or an attenuator or a pressure gauge all types of uses can be made of that how brilliant
As with most Nobel Prize winning concepts: the solution is so elegant, I could have invented it myself
the interviewer doesn't seems very bright in physics but his ability to scrutinize the facts and then ask uncanny questions are commendable
At 1:40, when you talk about the size(or diameter) of the sphere being equal to wavelength of light, which part of the spectrum are you actually referring to?
2:52
Why? Why does the glass sphere acquire momentum downwards?
If you expell/throw/whatever something in a direction, you're going to be pushed in the opposite direction.
Ah, see, that's why I find it so hard to move when it's bright outside. Great info, thanks! I will stay inside now.
I miss sixty symbols's videos, kindly upload them more frequently
I was using optical tweezers back in college. It was used to turn and rotate cells. I was also using electricity standing waves to do the same thing. But these lasers were more troublesome than the electricity method. So just replace the glass bead with a human cell and that is what I was doing.
Hey..how come same light is deflecting in two different directions..one upwards and one downwards?
Why wasn't there a 2016 & 2017 Nobel Prize video?
What size and mass is the sphere?
How powerful is the laser?
All scientific researches are published for everyone to read. For the technical aspects and the full explanation of the processes described above, you need to search for the original papers submitted by the authors. On the second case though, the research said it was done while Dr.Strickland was a Ph.D. student so expect a > 100-page read.
There is a video of a dude levitating diamond dust with one of his overclocked lasers, you can actually see it
4:30 - could you not just shine two lasers in opposite directions in the same vector? So one is pushing it left but the other is pushing it right
Then you'd use half the laser intensity
Somewhere in the Dan Simmons 'Hyperion' series they briefly describe a white laser used as a spotlight from the distance of AU
Please explain an experiment on reversibility if fluid motion
The momentum comes from the time lost in slowing the light through the sphere in order to refract it
When you run water over a boiled egg in the bottom of a pot, I've noticed the egg will tend to roll itself into the stream, ending up basically centered under the water. I only noticed this recently, and found it really funny that it wasn't something I'd heard about growing up as, like, some pop science tidbit from Bill Nye or something. Maybe it's common knowledge, and I just missed that episode...
What exactly do you mean?
It's similar to how a strong stream of air can capture a capture a round object. If the fluid hits the round object off center, it will follow the curve and pull the object towards the center of the stream (the result is even stronger if the object can spin)
I think some demos were done with a ping-pong ball and a hair dryer
Just out of intrigue, isn't the principal of levitation mentioned in the video very much similar to acoustic levitation. But I know for sure that in acoustic levitation you need nodes of interference from different frequencies to levitate things can't see how that happens for a laser.
Love these coffee-chat style talks. Super informative but super casual
Great video! Smarter Every Day sent me over here, and now I'm a subscriber.
Well, it sure _felt_ like a five-minute video ;)
false.
I like this Merrifield fellow. He's quite intelligent in his explanations.
Oh neat. I remembering reading about this easily a decade ago. Glad they got recognized.
this channel helps me live my life
The 'tweezer' seems to have a venturi effect, around the sphere, (or maybe inverse venturi), and the sphere looks to have a positive bouyancy in the beam.
I may be reading too much into it.
This seems like an optical version of floating a ping-pong ball in the middle of a stream of flowing air. The ball is stable within the beam precisely because, if it happens to wander off-center for a moment, it deflects the air flow in just the right direction that the recoil pushes it back towards the center.
There are also some experiments on "sound levitation" on RUclips that perhaps are an acoustic analog of the optical tweezers.
Can you do a actual double split experiment that would be the coolest thing on RUclips
Extremely well explained
that is so cool .. darn! in those moments i seriously love physics!
if you want to get more people into stem .. show them such hands on, brilliant solutions for physical problems.
It’s about time!
I know that a wave with a large amplitude is low energy (e.g. radio vs gamma), so how could it destroy the amplifier as opposed to the shorter waves?
Great video. Explained in a very amazing and intuitive manner.
Very clear explanation. Thanks to Destin for pointing me to this!
Is it possible to measure gravitational waves using this very sensitive apparatus? (incidentally, LIGO also uses light but a very different property of light)
So optical tweezers are a Piezoelectric locking or rather balancing effect.
Wait, but if there is some mechanical process of the photons which get refracted hitting the sphere, mustn't the photons lose just a little momentum so they aren't moving at lightspeed anymore or am I missing something?
What if, instead of the recombiner, they put a mirror, so light gets amplified again, and the "light splitter gizmo" works as recombiner, too? (if it's optical like in the drawing)
What makes the beam combiner stronger than the amplifier, such that it doesn't melt?
While watching another Sixty Symbols video (Feynman Diagrams) I followed up a passing reference to a guy called Stueckelberg. Now I'd like to suggest a video about Baron Ernst Carl Gerlach Stueckelberg von Breidenbach zu Breidenstein und Melsbach, to give him his full name.
Quoting from Wikipedia: "Stueckelberg developed the vector boson exchange model as the theoretical explanation of the strong nuclear force in 1935. Discussions with Pauli led Stueckelberg to drop the idea, however. It was rediscovered by Hideki Yukawa, who won a Nobel Prize for his work in 1949 - *the first of several Nobel Prizes awarded for work which Stueckelberg contributed to, without recognition* ".
11:36 Of all the ways of sticking random things together, 99.999 % of them already exist on RUclips.
I have a few newbie questions. Why does the glass/ plastic sphere stay in place in the laser beam? Although the gaussian beam is brightest in the middle is the gradient the same downwards and upwards? if so why is the particle displaced slightly up and not down. force of gravity acting on it should keep it displaced slightly down in my newbie mind.
Thank you this was easy to understand and helped me loads.
I gave a round of clapping in real life for the genious the not-moving-back-and-forth method was for the laser tweezer. That's really freaking genious.
I find it so hard to fathom how physicists can use single particles and molecules in their experiments and measurements. Maybe you could do a video explaining it!
Why is the light scattered in that pattern after entering the glass bead from being focused from the microscope lens? And why does it diverge from that specific point within the bead? Cheers.
I wonder if this kind of technology if scaled up can be used to help with a space elevator 'car'. Using lasers strong enough to beam straight upwards. It may be more economically or environmentally efficient/friendly.
This is a very informative videos about this topic. Really really mind-blowing and easy to understand this clever new discovery in Physics
i didn't understand, how the lens is manipulating momentum, i mean the mass of light refracting from the other side is same as that hitting the sphere, how can area of light emerging , change the momentum?
Brilliant all around
Fascinating. So presumably by measuring the movement of the sphere in the beam researchers should be able to design gravitometers to measure micro changes in gravity. If this is the case I assume that with sufficient resolution you would be able to measure inhomogeneities under the earth surface. Say waterpipes or mine shafts?
Haven't they been using the pulse synthesis thing in radar systems for quite a long time?
Awesome explanation and great questions
To keep the glass sphere from drifting off, can’t you just have a beam in the opposite direction as well?
I wonder if this could be used to measure whether ordinary matter repels antimatter
@10:47 The professor uses his thumb and pinky finger to show the size of something? Is that wierd to anyone else??
How does the same light passing through the same medium gets reflected in two different directions?
Just how small are these spheres? Does this scale up or is there and upper limit because of gravity?