Levitating tiny diamonds with lasers!

[Rivem]

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 get that man. I've already been in college a bit longer than I should have been, but I was set to graduate this year if I hadn't taken this semester off. Was going to have to make my grad school plans, but now they'll be pushed back a year. I like the idea of learning more and getting more academic recognition, but I don't know that I could continue and take another more academic degree either.

Somebody like you already has cool stuff going on and potential new business opportunities outside of school, so you definitely don't have to worry about grad school. Definitely looking forward to new videos and potentially seeing you on TV though!



I might have to read a bit on this problem. I'm a bit too rusty on the E&M physics to plan out that sort of code right now, but I did a few similar problems a while back.

Speaking of that, I'd appreciate a more technical laser book list if you have some good ones in mind. Was planning to take a more advanced optics course to satisfy my curiosity, but that's not possible anymore.

 

[styropyro]

I graduated at 23, so I was bit older than a lot of my classmates. Due to poor planning I took a year off between HS and college, but looking back I think it helped me out in the end. During my last semester at college, I went to my advisement and found out that I had 18 credit hours of gen eds that I hadn't taken, and couldn't graduate without them. I had taken a ton of extra math/science classes that seemed interesting, and always was doing 15-18 credits a semester, but skipping those stupid gen eds almost made me stay there another semester. So while taking 3 400 level chem classes and a 400 level math class, I started cramming for CLEP tests and knocked out a total of 32 credit hours my last semester, while also working in the lab, doing YT, and training a shitload of martial arts. I was so sleep deprived by the end I was hallucinating ants crawling over my math final. I loved what I had learned in college, but that kinda strain really dampened my desire to continue in academia.

As for books, I'll give some recommendations, but do realize my interests are very classical and I don't have any links to modern/diode based stuff.


Solid State Laser Engineering. My top pick. I had been messing with lasers for years but never understood how they worked. After finishing diferential equations 1 and an undergrad quantum class I read this book cover to cover and learned SO much. Even if you don't want to build a ruby/flashlamp pumped laser, the info is very good.
https://www.ebay.com/itm/Solid-Stat...id=2137676&hash=item3f6b1ebd21:i:272380116257

curious about the HUGE lasers used in fusion experiments? This book was first written in the 80s I think, but scientists still use huge Nd:glass slabs for ICF experiments so the info is still relevant.
https://www.ebay.com/itm/High-Peak-...28035&hash=item51e3607132:g:7U4AAMXQWzNSlN~wv

A great book on optical design:
https://www.ebay.com/itm/Engineerin...pid=170514&hash=item3f712013ac:i:272480867244

I could recommend books on chemical lasers too.

 

[Zom-B]

I'm gonna up a particle with a laser at 250mW and then turn it up to 2W+ to see if I can blow that shit up (or maybe it will be launched?)

 

[Zom-B]

This procedure works wonders! I forgot I have my MXDL at work to be wavelength-tested, so I had to do with an LPC-826 and a crappy driver bringing it to 180mW.

Levitating Sharpie-particles is so easy!! I was able to levitate new particles down to 50mW, and just below that it instantly loses any already captured particles.

 

[Zom-B]

So the M140 CAN levitate despite idiotically inconvenient beam profile. It doesn't even matter if the long or short axis is horizontal. It does matter that I choose a power setting at which the beam looks somewhat gaussian. If I switch the power to max while levitating (using a switch, not a pot), the particle is gondor. I don't know if it's obliterated or just flew off because the changed beam shape.

 

[Atomicrox]

Great video!
Can you post a link to the diamond powder? I found many on ebay, but none that have the specs on your label.

 

[styropyro]

Great video!
Can you post a link to the diamond powder? I found many on ebay, but none that have the specs on your label.

Right here! https://www.ebay.com/itm/Diamond-Po...hash=item33b9766282:m:mMjW1Fp6QAga58e4I-_Pe-A

So the M140 CAN levitate despite idiotically inconvenient beam profile. It doesn't even matter if the long or short axis is horizontal. It does matter that I choose a power setting at which the beam looks somewhat gaussian. If I switch the power to max while levitating (using a switch, not a pot), the particle is gondor. I don't know if it's obliterated or just flew off because the changed beam shape.

That is interesting about the change in power causing the particle to fly off! The wikipedia article on optical tweezers may actually explain this effect in the derivation of force on a point dipole in the field produced by the laser.

After starting with the Lorentz force, the author ends up at this step:

The magnitude of E x B is just (4π x 10^7) times the power density. The author says the term d/dt(E x B) averages to 0 because the laser power is not fluctuating much relative to the wave's frequency.

In your case though, you hit a switch and the power rises extremely rapidly, meaning that term is no longer negligible and a force appears pointing away from the laser! Without knowing the rise time of the laser power I can't calculate it, but this could definitely be why the particles fly off.

 

[CurtisOliver]

Sorry for the slight necro. But just wanted to wish Drake well done on getting referenced in this article by Popular Mechanics.

You Can Build Your Own 'Laser Tweezers'

Good job. :beer:
You are most certainly getting recognised for your videos. Excellent!

 

[Skittles]

Do only sharpie and diamonds work? Is there anything else I can use? I don't have any sharpies around so I tried other markers and no luck lol. I need to buy some sharpies now.

Or maybe I need the right laser.

 

[Encap]

For a more detailed framework of understanding "optical tweezers" but not a complete real explanation of this + some interesting history of same as well, see: https://en.wikipedia.org/wiki/Optical_tweezers


:can:

 

[Zom-B]

Do only sharpie and diamonds work? Is there anything else I can use? I don't have any sharpies around so I tried other markers and no luck lol. I need to buy some sharpies now.

Or maybe I need the right laser.

Any old black felt-tip might work. I used a DVD permanent marker.