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Thread: Call that a laser? Now this is a laser!

  1. #21
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    The goal is to fire once every 5 hours... not minutes... at the powers and heat this thing generates, it's incredible they can get it down to that low!

    --DDL
    I suffer from the Dunning–Kruger effect... daily.

  2. #22
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    Apr 2007
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    Toronto Canada
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    My dad told me a funny story about same type of laser being used. They had a radio playing in the facility and with every flash which sounded like bottle of champagne being opened (every 5 minutes)....from outside it sounded like a party. Their boss came over and asked the reason for celebration.
    I hired an Italian guy to do my wires. Now they look like spaghetti!

  3. #23
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    Jan 2007
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    Cupertino, California
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    Yeah, flashlamps sound like that when they are large enough.

  4. #24
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    Quote Originally Posted by heroic View Post
    destroy diode pumps. The laser only fires once every few minutes anyway, since the USA does not have a spare power plant to run the thing.

    -J.
    Hmm what about fiber optics?
    I hired an Italian guy to do my wires. Now they look like spaghetti!

  5. #25
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    UK
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    QUOTE:

    NIF's 192 laser beams travel a long path, about 1,000 feet, from their birth at one of the two master oscillators to the center of the target chamber. As the beams move through NIF's amplifiers, their energy increases exponentially. From beginning to end, the beams' total energy grows from one-billionth of a joule to four million joules, a factor of more than a quadrillion – and it all happens in less than 25 billionths of a second.

    Each master oscillator generates a very small, low-energy laser pulse. The pulse may range from 100 trillionths to 25 billionths of a second long, and has a specific temporal shape as requested by NIF experimenters. The low-energy pulse is carried on optical fibers to 48 preamplifier modules for initial amplification and beam conditioning. In the preamplifiers the energy is increased by a factor of ten billion to a few joules. The 48 beams from the 48 preamplifiers are then split into four beams each for injection into the 192 main laser amplifier beamlines (see Injection Laser System).
    Each beam zooms through two systems of large glass amplifiers, first through the power amplifier and then into the main amplifier. In the main amplifier, a special optical switch called a plasma electrode Pockels cell (PEPC) traps the light, forcing it to travel back and forth four times through 11 sets of laser amplifier glass slabs before it can exit the main amplifier cavity. Without this optical switch, the NIF main laser building would have to be about 750 feet longer to achieve the same amplification.

    From the main amplifier, the beam makes a final pass through the power amplifier before speeding into the target chamber. As the pulse's energy is being amplified, a special deformable mirror and other devices (see NIF Optics) ensure that the beams are of high quality, uniformity and smoothness.
    NIF's large glass amplifiers are unique. Other large laser systems use a series of amplifiers of increasing size to raise the beam's energy. NIF's amplifiers are all the same size and use more than 3,000 one-meter-long slabs of special phosphate glass doped with neodymium atoms.

    A split second before the initial weak laser pulse begins life at the master oscillator, more than 7,500 two-meter-long flashlamps, powered by huge capacitors that store electricity (see Power Conditioning System), energize the neodymium atoms in the amplifier glass by bathing them in intense white light (see How Lasers Work). When the laser beams leave the preamplifiers, the amplifiers are already powered up and ready to receive them. After passing through all the amplifiers, each NIF laser beam has been amplified to about 20,000 joules of energy.

    A complex system of special mirrors in two ten-story steel structures known as "switchyards" rearrange the parallel, linear array of 192 laser beams into a spherical configuration so that the beams can be focused into the center of the target chamber. Among the stiffest structures ever built, the switchyard's towers are built to resist vibration and are firmly anchored to the inside of the building's four-foot-thick reinforced concrete walls. Each beam passes through a final optics assembly that converts the wavelength of the laser from infrared to ultraviolet and is focused through a final focus lens onto a target located at the chamber's center. Targets are located with a precision that is measured in fractions of the thickness of a sheet of paper. The ability to achieve such precise alignment has been demonstrated with the first four activated beams (see NIF Early Light) and with subsequent experimental tests as additional beams were brought online.
    Last edited by White-Light; 02-21-2009 at 04:53. Reason: Some of the text didn't paste

  6. #26
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    Quote Originally Posted by heroic View Post
    My friend Brian presented that :-)

    -J.
    Name dropper
    Brian Cox is ace - I love his enthusiastic delivery and he makes the stuff he talks about sound easy to understand. Put it this way my girlfriend sits and watches programs he presents with me - and thats something!
    Excellent program - keep them coming Brian

    Rob
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
    -----------------------------------------------------------------------------------------------
    Laserists do it by the nanometre.

    Stanwax Laser is a Corporate Member of Ilda

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