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incinerator
Elite Laser
Joined: 05 Aug 2007
Posts: 207
Location: canada
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likewhat
55mW Advanced Wicked Laser
Joined: 10 Jun 2007
Posts: 62
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 Posted: 1/01/08, 3:18 PM Post subject: |
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It is just the same thing as a green laser pen. It falls under the generic name of a solid state laser, that is a laser than uses some kind of a crystal or piece of doped glass as the gain medium.
The laser pens usually use vanadate crystal instead of YAG though. The reason they are green is because they have an additional nonlinear crystal in them that doubles the frequency from an invisible IR color to green. |
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godfrey
Wicked Lasers Master
Joined: 23 Feb 2006
Posts: 957
Location: St. Louis, MO
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| Posted: 2/09/08, 10:24 PM Post subject: |
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Digging up an old(er) post
Stollen from Wikipedia - cause it's been too long since I've covered this topic.
Nd:YAG (neodymium-doped yttrium aluminium garnet; Nd:Y3Al5O12) is a crystal that is used as a lasing medium for solid-state lasers. The dopant, triply ionized neodymium, typically replaces yttrium in the crystal structure of the yttrium aluminium garnet, since they are of similar size. Generally the crystalline host is doped with around 1% neodymium by weight.
Nd:YAG lasers are optically pumped using a flashlamp or laser diodes. They are one of the most common types of laser, and are used for many different applications.
Nd:YAG lasers typically emit light with a wavelength of 1064 nm, in the infrared. However, there are also transitions near 940, 1120, 1320, and 1440 nm. Nd:YAG lasers operate in both pulsed and continuous mode. Pulsed Nd:YAG lasers are typically operated in the so called Q-switching mode: An optical switch is inserted in the laser cavity waiting for a maximum population inversion in the neodymium ions before it opens. Then the light wave can run through the cavity, depopulating the excited laser medium at maximum population inversion. In this Q-switched mode output powers of 20 megawatts and pulse durations of less than 10 nanoseconds are achieved.
Nd:YAG absorbs mostly in the bands between 730-760 nm and 790-820 nm. Krypton flashlamps, with high output at those bands, are therefore more efficient for pumping Nd:YAG lasers than the xenon lamps, which produce more white light and hence more energy therefore goes wasted.
The amount of the neodymium dopant in the material varies according to its use. For continual wave output, the doping is significantly lower than for pulsed lasers. The lightly doped CW rods can be optically distinguished by being less colored, almost white, while higher-doped rods are pink-purplish.
Other common host materials for neodymium are: YLF (yttrium lithium fluoride, 1047 and 1053 nm), YVO4 (yttrium orthovanadate, 1064 nm), and glass. A particular host material is chosen in order to obtain a desired combination of optical, mechanical, and thermal properties. Nd:YAG lasers and variants are pumped either by flash lamps, continuous gas discharge lamps, or near-infrared laser diodes (DPSS lasers). Prestabilized laser (PSL) types of Nd:YAG lasers have proved to be particularly useful in providing the main beams for gravitational wave interferometers such as LIGO, VIRGO, GEO600 and TAMA.
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King K
Wicked Lasers God
Joined: 06 Sep 2006
Posts: 1584
Picture(s): 95
Movie(s): 35
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| Posted: 2/10/08, 11:53 AM Post subject: |
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The reason why Nd:YAG is used in as a gain medium in multi-watt lasers instead of Nd:YVO4 is because Nd:YVO4 may gray-line, Nd:YAG is usually much less efficient but does not gray-line easily.
KTP is frequently used as a frequency-doubler non-linear crystal after the Nd:YAG to lase at 532nm green.
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incinerator
Elite Laser
Joined: 05 Aug 2007
Posts: 207
Location: canada
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| Posted: 4/17/08, 5:43 PM Post subject: |
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| godfrey wrote: |
Digging up an old(er) post
Stollen from Wikipedia - cause it's been too long since I've covered this topic.
Nd:YAG (neodymium-doped yttrium aluminium garnet; Nd:Y3Al5O12) is a crystal that is used as a lasing medium for solid-state lasers. The dopant, triply ionized neodymium, typically replaces yttrium in the crystal structure of the yttrium aluminium garnet, since they are of similar size. Generally the crystalline host is doped with around 1% neodymium by weight.
Nd:YAG lasers are optically pumped using a flashlamp or laser diodes. They are one of the most common types of laser, and are used for many different applications.
Nd:YAG lasers typically emit light with a wavelength of 1064 nm, in the infrared. However, there are also transitions near 940, 1120, 1320, and 1440 nm. Nd:YAG lasers operate in both pulsed and continuous mode. Pulsed Nd:YAG lasers are typically operated in the so called Q-switching mode: An optical switch is inserted in the laser cavity waiting for a maximum population inversion in the neodymium ions before it opens. Then the light wave can run through the cavity, depopulating the excited laser medium at maximum population inversion. In this Q-switched mode output powers of 20 megawatts and pulse durations of less than 10 nanoseconds are achieved.
Nd:YAG absorbs mostly in the bands between 730-760 nm and 790-820 nm. Krypton flashlamps, with high output at those bands, are therefore more efficient for pumping Nd:YAG lasers than the xenon lamps, which produce more white light and hence more energy therefore goes wasted.
The amount of the neodymium dopant in the material varies according to its use. For continual wave output, the doping is significantly lower than for pulsed lasers. The lightly doped CW rods can be optically distinguished by being less colored, almost white, while higher-doped rods are pink-purplish.
Other common host materials for neodymium are: YLF (yttrium lithium fluoride, 1047 and 1053 nm), YVO4 (yttrium orthovanadate, 1064 nm), and glass. A particular host material is chosen in order to obtain a desired combination of optical, mechanical, and thermal properties. Nd:YAG lasers and variants are pumped either by flash lamps, continuous gas discharge lamps, or near-infrared laser diodes (DPSS lasers). Prestabilized laser (PSL) types of Nd:YAG lasers have proved to be particularly useful in providing the main beams for gravitational wave interferometers such as LIGO, VIRGO, GEO600 and TAMA.
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cool! "Neodymium" I have one of those, magnets http://www.kjmagnetics.com/proddetail.asp?prod=BX0X0X0 |
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Bluefan
Fusion Laser
Joined: 20 Apr 2008
Posts: 283
Movie(s): 1
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| Posted: 5/17/08, 12:40 PM Post subject: |
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[quote="incinerator"]... cool! "Neodymium" I have one of those, magnets ...
Me too, but what, are you trying to get your magnet to lase?  |
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