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Femtosecond laser holograms

Eudaimonium

Eudaimonium

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Hey people,

Came across this video:

https://www.youtube.com/watch?v=AoWi10YVmfE


It's basically the idea we've all been around at, earlier - using the breaking of air with high intensity focused laser to create a hologram mid-air. We all kinda dropped it at the idea that sticking your hand in it will create an awesome hospitalization bill and a story to tell.

They apparently fixed that problem.

Thoughts?
 





Very cool stuff, although it seems this technology is very, very expensive. A femtosecond laser that also ionize air.. I wonder what system they use. Maybe modelocked quadrupled Nd:YAG? Or excimer lasers? Who knows..
 
doubleone44 said:
Very cool stuff, although it seems this technology is very, very expensive. A femtosecond laser that also ionize air.. I wonder what system they use. Maybe modelocked quadrupled Nd:YAG? Or excimer lasers? Who knows..
Click to expand...
I doubt it could be a pumped YAG or other neodymium - no pumping source works that fast.

Even common diode semiconductors take what, a dozen nanoseconds to switch states? So how can they claim femto-second level switching?

Another thing, femtosecond level speeds are somewhat irrelevant if it's all going through a galvo set anyway, they are FAR slower than that.

Also, regardless of switching speeds, you still need to focus enough energy to break down air. That is a lot of energy, no way around that - so this approach to display technology will ALWAYS inheretly be very dangerous.

Even in the demo video, whoever is the owner of that finger appears to be quite afraid to stick it into the projection for too long, as if he's poking an open candle's flame.
 
So we could use this technology to make a hologram of a shark... with a laser attached to it's forehead.
 
very cool. I'd love to see this put into some forum of tactical training once it becomes more advanced. Like a video game lol
 
Eudaimonium said:
I doubt it could be a pumped YAG or other neodymium - no pumping source works that fast.
Click to expand...

Nd:glass can make picosecond pulses and those with some technique can be converted to femtoseconds.

Though Ti and Yb are more common dopants for femtosecond lasers.
 
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