Hello There.

[DANfour20]

:wave: Hi, Im new here.
Ive read a few posts before but decided to register now.

My "Experience" with lasers.

cheap red one I bought from a fair in my town. probably around 2000.
(various other cheap red ones)

2010 I got a blu ray laser, violet advertised as 1mW but the sticker on the pen said 5mW. was pretty cool. i attached it to my binoculars for some long distance lasing. tried to pot mod it but i broke it trying to get it out of its housing (it was glued in i think).

2011 - just recently bought a 1mW green laser of ebay for 4.70gbp free p+p. from user: besteworld

I have a few questions if i may,

my pens beam is visible in daylight but only at the right angle, at night it is ultra visible when pointing at buildings (street level) and just as bright when pointing into the nightsky.
I think it may be more then the 1mW stated??

Why are some pointers so expensive whereas similar if not the same spec lasers can be bought of ebay for under 5gbp? other then the clearly better housing of the components.

Is there anything pretty cool i could do with it to impress my friends? with household items?

thank you all for reading.

 

[lasersbee]

to the Forum....
Don't forget to read the FAQs...the Stickies
and the Forum Rules..

If you plan on buying anything on the Forum....
PLEASE read this first...

6 Steps To Prevent You From Getting Scammed

and this....

33 Reasons NOT to Buy From Wicked Lasers

Enjoy your stay...


Jerry

 

[Sigurthr]

Price reflects many things, not only power output. Sometimes you're paying for convenience (ordering from a US business), sometimes for quality assurance, sometimes for a rare or hard to produce wavelength, sometimes (most of the time) places just charge a lot to make money. Often, eBay descriptions are VERY wrong, and since you cannot actually tell what you're buying until you have it (and in the case of lasers, also have a calibrated LPM to test it on) eBay sellers can get away with ripping you off. Mark a 1mW laser as 5mW, buyer will never know the difference. Sell 405's a blue, when they're really violet. Sometimes lasers sold on eBay were defective or factory seconds.

Gas lasers and DPSS lasers are generally a higher price than direct diode lasers because the technology is a lot more complex and sensitive. So, a HeNe may only put out 1mW, and cost >$50, where as a 5mW 670nm diode laser may be only $2. The difference is in the wavelength and how the laser functions. HeNe's run on a high voltage power supply and have a big ol' glowing tube in them. They produce light mostly at 638.2nm which is more visible than the cheap diode's 670nm. DPSS lasers (most commonly 532nm and 473nm) use a VERY high power infrared diode to power special delicately aligned crystals inside which change the light to be visible. This is a very inefficient process, and where 700mW of IR goes in, only 50mW of Green may come out.

You also pay more if the laser's beam is of better quality; single mode vs. multimode. TEM00 vs TEM03, etc. TEM (transverse electric modes) are definitions of the shape of the beam/spot the laser produces. TEM00 is a perfect circle and gives you the best divergence.

Be aware that your 1 or 5mW 405nm (violet) pointer may actually be up to 100mW. eBay restrics sellers to only 5mW for USA and 1mW for many other countries. So, they take a 1mW or 5mW sticker and put it on their laser, knowing full well that most people can't tell the difference. Anything over 5mW can potentially cause damage to your vision and blindness.

Lasers under 570nm tend to fluoresce many household items. 405's do it the best, try shining the laser at various items which look to be white, blue, green, yellow, or orange. Sometimes red colored objects as well. If the object fluoresces, the spot will change color and appear brighter. If you can find something that fluoresces a bright green or greenish yellow, the brightness of your laser's spot on that object will give you an indication of the laser's true brightness. We humans don't see 405nm very well.

The reason the laser beam seems brighter at certain angles has to do with how the light is scattered by the air mollecules and dust.

 

[DANfour20]

Price reflects many things, not only power output. Sometimes you're paying for convenience (ordering from a US business), sometimes for quality assurance, sometimes for a rare or hard to produce wavelength, sometimes (most of the time) places just charge a lot to make money. Often, eBay descriptions are VERY wrong, and since you cannot actually tell what you're buying until you have it (and in the case of lasers, also have a calibrated LPM to test it on) eBay sellers can get away with ripping you off. Mark a 1mW laser as 5mW, buyer will never know the difference. Sell 405's a blue, when they're really violet. Sometimes lasers sold on eBay were defective or factory seconds.

Gas lasers and DPSS lasers are generally a higher price than direct diode lasers because the technology is a lot more complex and sensitive. So, a HeNe may only put out 1mW, and cost >$50, where as a 5mW 670nm diode laser may be only $2. The difference is in the wavelength and how the laser functions. HeNe's run on a high voltage power supply and have a big ol' glowing tube in them. They produce light mostly at 638.2nm which is more visible than the cheap diode's 670nm. DPSS lasers (most commonly 532nm and 473nm) use a VERY high power infrared diode to power special delicately aligned crystals inside which change the light to be visible. This is a very inefficient process, and where 700mW of IR goes in, only 50mW of Green may come out.

You also pay more if the laser's beam is of better quality; single mode vs. multimode. TEM00 vs TEM03, etc. TEM (transverse electric modes) are definitions of the shape of the beam/spot the laser produces. TEM00 is a perfect circle and gives you the best divergence.

Be aware that your 1 or 5mW 405nm (violet) pointer may actually be up to 100mW. eBay restrics sellers to only 5mW for USA and 1mW for many other countries. So, they take a 1mW or 5mW sticker and put it on their laser, knowing full well that most people can't tell the difference. Anything over 5mW can potentially cause damage to your vision and blindness.

Lasers under 570nm tend to fluoresce many household items. 405's do it the best, try shining the laser at various items which look to be white, blue, green, yellow, or orange. Sometimes red colored objects as well. If the object fluoresces, the spot will change color and appear brighter. If you can find something that fluoresces a bright green or greenish yellow, the brightness of your laser's spot on that object will give you an indication of the laser's true brightness. We humans don't see 405nm very well.

The reason the laser beam seems brighter at certain angles has to do with how the light is scattered by the air mollecules and dust.

I no longer have the <5mW violet laser pen, but yes it did fluoresce very well on white objects, and was amazing to play with glow in the dark materials.

I now have a <1mW (advertised) cheap green laser pointer.

How about cool things i could do with it? I tried burning with a magnifying glass but didn't even smoke a magazine cover lol.

 

[Sigurthr]

Yeah burning is rare below 95mW and depends mostly on the beamwidth. With a good focusing lens you can burn black materials at 50mW.