Levitating tiny diamonds with lasers!

[Deleted member 13229]

I first learned about optical trapping on this forum nearly a decade ago. At the time, I couldn't comprehend the science behind it, but I could easily do the experiment with a 200mW red laser. I decided to explore the idea again and make a video about it!

I say in the vid that you'll need a red laser, but any of your single mode lasers will probably do the trick.


https://www.youtube.com/watch?v=Sq7GaO8iqu8

 

[Alaskan]

Cool, I wish I had grown up to become the physics student you are, awesome.

 

[Deleted member 13229]

I was actually a chemistry student lol I just like physics.

 

[Alaskan]

It's all physics to me.

 

[ArcticDude]

Well that was freaking cool!! :bowdown:

Thanks for sharing it

 

[Gabe]

Yes super cool, I'll have to try the sharpie trick soon. I was really jealous, that 510nm green laser really looked like a higher powered 490-500nm pointer in a beautiful host, I was wondering which kidney you had to sell to get a diode in that wavelength which looked like it output like 50-75mW.

 

[RedCowboy]

That is Awesome !

I knew you could suspend matter in an electromagnetic field but I did not know it could be done with a laser beam, and that last bit about drawing in antimatter from seemingly nowhere and having an effect on the fabric of space time albeit with an extremely powerful laser has my mind racing with thoughts, very cool stuff.

-------------------------------------------------------------

It's all physics to me.

Says someone who may have been inside an actual alien tractor beam.

 

[Deleted member 13229]

Yes super cool, I'll have to try the sharpie trick soon. I was really jealous, that 510nm green laser really looked like a higher powered 490-500nm pointer in a beautiful host, I was wondering which kidney you had to sell to get a diode in that wavelength which looked like it output like 50-75mW.

Yeah the camera does make it look bluer than it really is...it is built into a black leadlight host BTW. Somewhere I have a <505nm diode but it is lost among my shit...

That is Awesome !

I knew you could suspend matter in an electromagnetic field but I did not know it could be done with a laser beam, and that last bit about drawing in antimatter from seemingly nowhere and having an effect on the fabric of space time albeit with an extremely powerful laser has my mind racing with thoughts, very cool stuff.

Yeah it is a crazy effect beyond what I can comprehend ATM. Scientists are trying to approach this limit with huge femtosecond lasers, but are still orders of magnitude off.

More reading if you're interested:
https://en.wikipedia.org/wiki/Schwinger_limit
https://en.wikipedia.org/wiki/Kugelblitz_(astrophysics)
https://en.wikipedia.org/wiki/Two-photon_physics

 

[steve001]

A very educational vid it's also commendable to see such vid where some youngun has not bought a laser simply to burn something.

 

[Hemlock_Mike]

Would this work in an evacuated tube?
That would eliminate air currents.
HM

 

[Rivem]

Awesome video Styro! I knew you were in some sort of storage unit.

Is the storage unit back near home in IL or near school?

Really liked seeing some math that I could understand. Wouldn't have known to treat the particle as a dipole though. Still lacking a lot of optics and materials knowledge I'd like to have, but I guess I already know enough to suit my degree.

Would this work in an evacuated tube?
That would eliminate air currents.
HM

As long as you could manipulate things through the container to get the particles entrapped, yes.

I really wonder what it'd look like with a high power DPSS or 405nm laser in a vacuum. Presumably, that'd be a good way to pick up more particles.

 

[Deleted member 13229]

A very educational vid it's also commendable to see such vid where some youngun has not bought a laser simply to burn something.

Thanks! While I do enjoy burning crap with lasers, laser science is super interesting and there's nothing like it.

Would this work in an evacuated tube?
That would eliminate air currents.
HM

Oh yeah it'll work a lot better in a vacuum. Without air currents you are only fighting gravity (and other EM forces I guess)

 

[Gabe]

I tried the sharpie method with one of my single mode lasers this evening and it worked! Although there's one thing I still don't understand, what exactly is being levitated when you put a sharpie in the beam? I doubt it's anything clear, so is it maybe a bit of felt or smoke or some other product of combustion/burning? Any ideas?

 

[Deleted member 13229]

Awesome video Styro! I knew you were in some sort of storage unit.

Is the storage unit back near home in IL or near school?

Really liked seeing some math that I could understand. Wouldn't have known to treat the particle as a dipole though. Still lacking a lot of optics and materials knowledge I'd like to have, but I guess I already know enough to suit my degree.

The storage shed is in IL. I'm not in grad school any more, I dropped out. Don't get me wrong, UR had some great faculty and amazing facilities, but I realized that the academic lifestyle is definitely not for me at this point in my life. Some day I'd like to do a PhD, but for the time being I have some of my own ideas that I want to run with. Plus there's the chance I'll do some TV work and that would be awesome.

It would be interesting to see the solutions if you modeled the particle as a volume dielectric that is polarized in the field. For a particle that is say a micron diameter sphere, I wonder how far off the force would be from the example of the perfect dipole. I wish I knew computer math, because this shouldn't be too hard to solve with numerical integration.

I tried the sharpie method with one of my single mode lasers this evening and it worked! Although there's one thing I still don't understand, what exactly is being levitated when you put a sharpie in the beam? I doubt it's anything clear, so is it maybe a bit of felt or smoke or some other product of combustion/burning? Any ideas?

When the sharpie is in the beam it is being burned, you can see the smoke coming off. That means the chemical composition has been changed. My guess is that you are trapping tiny particles of a material with high carbon content. They are very tiny so they don't need to be clear as a bulk material. Most dark materials will be essentially transparent when shaved down to ~100nm.

 

[Gabe]

When the sharpie is in the beam it is being burned, you can see the smoke coming off. That means the chemical composition has been changed. My guess is that you are trapping tiny particles of a material with high carbon content. They are very tiny so they don't need to be clear as a bulk material. Most dark materials will be essentially transparent when shaved down to ~100nm.

Yes that is true, I didn't think about that. Things don't really interact with visible light that much when they're smaller than the wavelengths themselves.

 

[Deleted member 13229]

^What about atoms? A single atom can absorb a photon of say 500nm, even though the atom is much, much smaller than that. This is where the particle (photon) depiction of light is more useful. Light is weird...lol