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How to make ebay lasers less power

moh17

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After try and error and some luck. I found a way that can make Some cheap ebay lasers safe. First, check that the laser can run with one battery; not all lasers work with one battery. Second, get over 100 ohm resestor; I used two resistors 100 ohm and 10 ohm. Finally, get any small metal cab from a pen or pencil and solder it to one side of the resistor then drop them to the battery holder. Add one battery and you should see the laser much dimmer. Here are some pictures for the laser Before and After


mod.jpg


Before modifying the laser

before.jpg


After modification

after.jpg


:thanks:

Note: You will not see the laser dot unless you close the light.
 
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Cyparagon

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Your diode is no longer lasing, and you've lost your current regulation. This means the beam quality and power stability will be significantly worse.

Dimmer might technically mean safer, but the class 3R if your keychain is already safe enough.
 

moh17

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Your diode is no longer lasing, and you've lost your current regulation. This means the beam quality and power stability will be significantly worse.

Dimmer might technically mean safer, but the class 3R if your keychain is already safe enough.

Yes, you are right but it's now safe. In the dark you can see the dot. I can shine the laser to CDs, white paper without warring. I believe it is less than 1 mW. I can not confirm until I measure the optical power; however, it is likely too low and probably safe. Most ebay lasers are over spec . I feel safe and happy 😄
 
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Cyparagon

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Do you dull all your kitchen knives too? :tinfoil:
 

moh17

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Do you dull all your kitchen knives too? :tinfoil:

:D I do not want to care too much. I have two mirrors at my room. shining a claimed 5mW ebay laser will be a risk. I have a laser engraver that currently run by a 5 W IR laser; In the past I was using M140 at 2W but it was not efficient enough. I'm planing to equip it with optical fiber laser where I can possibly add a more powerful laser. I do not have any problem with powerful lasers when they are used probably in a system where safety percussion is taken. Lasers are not toys and should be respected and treated with some care.

:thanks:
 
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joeyss

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Just get a moon filter for a telescope lens and a small orange lens test it on the LPF

moon filters are small and have 13% trans mission and the lens opposite of the lasers color should mop up the rest of it. It might be over kill with the 2.
 

Geoglow

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I thought the danger of the cheap lasers was that they used an UV source and halved the frequency to produce the violet light?

Can't you just use a cheap uv filter?
 

ChaosLord

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I thought the danger of the cheap lasers was that they used an UV source and halved the frequency to produce the violet light?

Can't you just use a cheap uv filter?

No, not uv. 532nm laser use IR pumps that are frequency doubled (halved wavelength). This laser isn't dpss, so there is no pump, just the laser diode.
 

Geoglow

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I meant IR filter and mixed up wavelength and frequency lol is using the IR pump the only way to get green lasers/a lot of these other colors, or are there diodes that put out each wavelength? Is there a reason that they are such specific wavelengths and not 533 or 531?

I mean, to make them less intense can't you just reduce the power?

I wouldn't call it making them safe. All lasers are safe if they are handled in the manner required for the type of laser you're using.

The lasers in the national ignition facility are safe, as long as you're behind a concrete and lead reinforced wall ;)
 
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moh17

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I meant IR filter and mixed up wavelength and frequency lol is using the IR pump the only way to get green lasers/a lot of these other colors, or are there diodes that put out each wavelength? Is there a reason that they are such specific wavelengths and not 533 or 531?

I mean, to make them less intense can't you just reduce the power?

I wouldn't call it making them safe. All lasers are safe if they are handled in the manner required for the type of laser you're using.

The lasers in the national ignition facility are safe, as long as you're behind a concrete and lead reinforced wall ;)

"I wouldn't call it making them safe. All lasers are safe if they are handled in the manner required for the type of laser you're using."

That is correct, however, accidents could happen even when precaution is taken. It takes less than a second for eye damage to occur; no matter how fast your eyes blink. Wearing safety glasses is essential when dealing with lasers > 5 mW and above.
 

H2Oxide

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I meant IR filter and mixed up wavelength and frequency lol is using the IR pump the only way to get green lasers/a lot of these other colors, or are there diodes that put out each wavelength? Is there a reason that they are such specific wavelengths and not 533 or 531?
TL;DR: kind of, no, and yes.

Diodes output specific wavelengths, the most common being:
375nm, 405nm, 445nm, 473nm, 485nm, 520(ish)nm, 635nm, 640nm, 650nm, 670nm(old), 671nm, 760nm, 785nm, 808nm, 848nm, 980nm, 1.064μm, 1.31μm, 1.48μm, 1.512μm, 1.55μm, 1.625μm, 1.654μm, 1.877μm, 2.004μm, 2.330μm, 2.680μm, 3.03μm, and last but not least, 3.33μm. (1μm = 1000nm)

I've probably missed some, but it doesn't really matter. As you can see, there really aren't many wavelengths for standard diodes. Some of the wavelengths can be changed with temperature, but it takes a huge shift in temperature for a tiny shift in wavelength. Plus, the human eye can't see half of the wavelengths listed. DPSS lasers provide a slightly larger spectrum of colors. They operate by changing the wavelength of light by passing it through a set crystals. For example, the way a typical red laser works is by powering a red diode. The way a green (532 not 520) laser pointer works is by pumping an Nd:YVO4 crystal (or YAG, but YVO4 is more common in pointers.) with one or more 808nm diodes, which creates light at 1.064μm. The light is then directed into another crystal, usually KTP, and 2 of the 1.064μm photons collide in the crystal to make a 532nm photon. (1064 ÷ 2 = 532) Shifting the wavelength of DPSS lasers with temperature doesn't work. That's why the wavelengths are so specific, but they are the only way to obtain wavelengths that are yellow and the extremely rare orange in pointer form. But there aren't just diode and DPSS lasers out there, for instance you can obtain pretty much any wavelength you want with a dye laser, and the Ti:sapphire is very tune-able as well. There are also gas lasers and metal vapor lasers that emit different wavelengths. Also in regards to your other question, there are 520nm diodes, which are green. :D (Sorry for the long reply)
 




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