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Author Topic: happy birthday to the laser, its 50!  (Read 1373 times)

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Offline AdminTopic starter

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happy birthday to the laser, its 50!
« on: May 06, 2010, 08:19:33 AM »
Yeap, the laser (or L.A.S.E.R. back in the day), has reached 50. You'll find one in everything from your DVD player, crazy military weapons, cold fusion reactors, countless measurement electronics, and even key chains. And one day, if we work hard enough, in evil world-conquering robots . . .

http://spectrum.ieee.org/semiconductors/optoelectronics/the-laser-at-50/0



and whoever wrote that article, this sentence makes no sense at all:
Quote
The laser starts with a short, low-energy laser pulse and stretches it to 10 000 times its length, amplifies it to 186 joules, then recompresses it to 167 femtoseconds.
« Last Edit: May 06, 2010, 08:26:48 AM by Admin »

Offline waltr

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Re: happy birthday to the laser, its 50!
« Reply #1 on: May 06, 2010, 11:15:39 AM »
and whoever wrote that article, this sentence makes no sense at all:
Quote
The laser starts with a short, low-energy laser pulse and stretches it to 10 000 times its length, amplifies it to 186 joules, then recompresses it to 167 femtoseconds.

[/quote]

That makes perfect sense once read in context. Remember what the LASER acronym means? Light AMPLIFICATION by Stimulated Emission of Radiation. For the "Highest power LASER" they are using a low power LASER (easy to obtain) to pump or Stimulate the High power LASER.
See this for more info on high power LASERs:
http://www.rp-photonics.com/high_power_lasers.html

Offline AdminTopic starter

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Re: happy birthday to the laser, its 50!
« Reply #2 on: May 06, 2010, 11:39:40 AM »
Well, they said stretch the length of a laser . . . you can't change the speed of light, hence that makes no sense. I assume they meant widen the diameter or split into multiple beams.

And you can't 'compress' a laser to a period of time, as again, light has a set speed.

On the naval base I often work at they have a cold fusion reactor. I got to see it and all the crazy laser stuff going on. They have a ton of lasers with stepper controlled mirrors to focus it all into a single spot within the chamber.

Offline waltr

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Re: happy birthday to the laser, its 50!
« Reply #3 on: May 06, 2010, 12:26:50 PM »
Quote
you can't change the speed of light

The speed of light is constant in a vacuum but does slow down as it passes through other media like glass.
http://en.wikipedia.org/wiki/Speed_of_light
Paragraph 4.

Offline z.s.tar.gz

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Re: happy birthday to the laser, its 50!
« Reply #4 on: May 06, 2010, 07:16:10 PM »
They've slowed light down to a crawl before by passing it through chrolo-something and the guy walked faster than the light right next to him.
I just wish I could find the video.
Save yourself the typing. Just call me Zach.

Offline corrado33

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Re: happy birthday to the laser, its 50!
« Reply #5 on: May 07, 2010, 08:41:53 AM »
Austin Powers - Sharks with lasers


Sharks with LAZERS!!!

Sorry, first thing I thought of. haha

Offline Soeren

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Re: happy birthday to the laser, its 50!
« Reply #6 on: May 07, 2010, 01:10:11 PM »
Hi,

They've slowed light down to a crawl before by passing it through chrolo-something and the guy walked faster than the light right next to him.
I just wish I could find the video.
Only because a Danish  ;D  ;D  ;D  (female) scientist proved it could be done by reducing it to like 60 km/h first.
Sorry, but the credit should go to her, as anyone can solve the Gordian Knot and the Columbus Egg once someone has shown the way.
I'm still waiting for the huge effects on all science that were a major concern when she did (as a "constant" which a lot of other stuff is based on was suddenly not all that constant anymore).


Some of the early LASERs (Acronyms should be in all capital) used xenon flashes for stimulation, perhaps it's a clumsy (error laden) description of that, leading to the very strange LASER stretching wording?
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline madsci1016

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Re: happy birthday to the laser, its 50!
« Reply #7 on: May 07, 2010, 01:56:01 PM »

Only because a Danish  ;D  ;D  ;D  (female) scientist proved it could be done by reducing it to like 60 km/h first.
Sorry, but the credit should go to her,

Well, if you want to be exact, the credit should go to the team she led that slowed it down to 38 MPH, A team of (some American) Harvard graduate students and a (American) Stanford professor in a laboratory here in Cambridge, Mass, USA.

I only know this because I have been in Cambridge for two weeks now for work, and was at a museum that had all this info.

 


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