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Thread: Beam expander

  1. #1
    Join Date
    May 2008
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    Default Beam expander

    Hi! My laser has a beam diameter of 0.6mm at the output. This makes it kind of hard to see the beam I think. I believe that a larger beam diameter would make it more visible and less dangerous as the energy density becomes lower. Has anyone here used a beam expander? Can you confirm my theories on this? Making one should be really easy...

    http://www.winlens.de/fileadmin/user...x_englisch.pdf

  2. #2
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    Oct 2006
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    Question

    What kind of laser are you using? Blue/Green/Red? Never had someone say their beam was too small...
    Love, peace, and grease,

    allthat... aka: aaron@pangolin

  3. #3
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    Default

    It's a 20mW uGreen DPSS from Uniphase. 533nm... I think it would have been nice to have a 3-5mm beam. But hmm... I'm not considering divergence here. It may be that size shortly after leaving the laser... A newer version of this laser specifies less than 1.2mrad but I have no data on that for my laser. Need to do some reserch...

  4. #4
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    Lightbulb

    That is a nice laser. I am nost sure it is a "laser show" laser, probably more for holigraphy or something. As opposed to expanding that beam, I'd just get a cheaper laser with a bigger beam, and more power. 20mW isn't really laser show power IMO either. I have just over 100mW in my RGB, and I still need a lil smoke to liven things up

  5. #5
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    Default

    Quote Originally Posted by allthatwhichis View Post
    I'd just get a cheaper laser with a bigger beam, and more power. 20mW isn't really laser show power IMO either. I have just over 100mW in my RGB, and I still need a lil smoke to liven things up
    Well, a laser doesn't get any cheaper than free... I have like 5 or 6 of them. They are used but in perfect condition. I know 20mW isn't much but it still looks supercool in mist or when it's snowing

    I know from Sam's Laser faq that the 20mW laser has the same laser diode that the 50mW version, and that can be pushed up to 100mW if you're evil. I know this is speculative but I'm determined to sacrifice one just to see how much they can take. Hey! Don't you think I'm beeing stupid know. They were free and I'm curious I once accidently ran one on more than twice the normal operating current and it survived. I was facing the opposite wall that the laser struck and I saw a strong green glow that was reflected of the wall behind my back. I was like "wow! that was a lot more than 20mW..."

  6. #6
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    Default

    Hey, if I had 5... I'd definatly sacrifice one in the name of science.

  7. #7
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    Default

    Exactly my idea...

  8. #8
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    Mar 2007
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    North Iowa
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    Default

    Danny ---

    How did you double the current? How much were you pushing through? I found that old leadlights smoked at about 380 mA. The power control board should have limited the current.

    Mike

  9. #9
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    Default

    Quote Originally Posted by Hemlock Mike View Post
    Danny ---

    How did you double the current? How much were you pushing through? I found that old leadlights smoked at about 380 mA. The power control board should have limited the current.

    Mike
    Well... I ran it on a current limited dc power supply just to see if it was working. This acts as a crude constant current supply if the current limit is set to a safe value and the voltage is turned up high enough. Normal current is about 750mA-1A for this laser. I accidently turned the wrong knob on the power supply feeding it the full 2A that my supply can give. I wouldn't recomend this if your uGreen laser is dear to you... But mine survived though.

  10. #10
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    Default

    I've got a lot of experience with the uGreen lasers. If you're not driving the 2 TECs inside, you're never going to get full power out of them. The KTP temperature is critical for efficiency and can easily double the output power when tuned correctly. The diode temperature is less critical, but still can get you 20-30% more power at a given current when tuned correctly. I had some 4600-020 heads that ran at up to 80mW without overdriving the 1.2W pump diode (1.6A max).

    If you have the HYB B controllers that go with the uGreen heads, I've documented that reasonably well. You can find the pdf in Sam's Laser FAQ

    http://www.repairfaq.org/sam/juhyb23.pdf

    I also have a written procedure for tuning a HYB B controller to any uGreen head.

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