240mW Green Laser Pen, retail $36.95
Manufactured by (Unknown)
Last updated 01-30-11

(In reference to the little packet I received from an Ebay seller at ~2:20pm PDT on 05-25-07):
{sung like the Foreigner song "Feels Like the First Time"}

This is a green DPSS pen-style laser module, advertised to emit 240mW at 532nm in the green part of the spectrum, but as you'll read below, that 240mW rating is a joke - and I'm not laughing.

It uses two AAA cells, which are held in its metal barrel.


To use the laser module, just aim it at something you wish to point out, and press & hold down the button on the barrel for as long as you need the laser spot. Release the button to turn the laser module back off. Yes, it really is as easy as that.

The laser module comes with a pocket clip, already attached. You know what it's for.
If not, slip the laser module into a shirt or pants pocket, and slide the clip over the outside of the fabric of the pocket when the module is being inserted into the pocket.

To change the batteries in your 240mW Green Laser Pen, unscrew and remove the tailcap, throw it in the {vulgar term for feces}bowl, yank that silver handle on the cistern down, and flush it away...O WAIT!!! YOU'LL NEED THAT!!! So just set it aside instead.

Tip the two used AAA cells out of the barrel and into your hand, and dispose of, recycle, or recharge them as you see fit.

Insert two new AAA cells into the barrel, flat-end (-) negative first. This is the opposite of how batteries are installed in most flashlights, so please pay attention to polarity here.

Screw the tailcap back on, and be done with it.
Aren't you glad you didn't flush away that tailcap now?

Current usage measures 307mA.

This is a laser, not a flashlight. So I won't throw it against the wall, stomp on it, try to drown it in the toilet bowl, run over it, swing it against the concrete floor of a patio, or inflict upon it punishments that flashlights may have inflicted upon them. So this section of the laser's web page will seem a bit more bare than this section of the web page on a page about a flashlight.

Green diode lasers are a lot different than those common red lasers you see all the time.

In a 640nm red laser, there's a red-emitting diode and a lens to collimate (focus) the beam.

In a 532nm green laser (module or larger size), there's a BIG infrared laser diode that generates laser light at 808nm, this is fired into a crystal containing the rare-earth element "neodymium". This crystal takes the 808nm infrared light and lases at 1064nm (yes, deeper in the infrared!). This 1064nm laser light comes out of the NdYV04 (neodymium yttrium vanadium oxide) crystal and is then shot into a second crystal (containing potassium, titanium, & phosphorus, usually called KTP) that doubles the frequency to 532nm - the bright green color you see. This light is then collimated (focused) by a lens and emerges out the laser's "business end". Just before the lens, there's a filter that removes any stray IR (infrared) rays from the pump diode and the neodymium crystal. You don't want that stuff in your green beam, trust me. :-)

This is why green diode lasers are so much more expensive than red ones. Lots of itty bitty parts, and they all need to be aligned by hand. If the polarisation is "off", one or both crystals need to be turned. With red diode lasers, you just slap in the diode and slap a lens in front of it.

VERY IMPORTANT!!! This laser is NOT a toy, and you MUST NOT shine it into your eyes, other people's eyes, pets' eyes, for that matter, the eyes of any person or animal you encounter. Eye damage can occur faster than the blink reflex can protect them, regardless of what species' eyes you irradiate with this laser. So just don't do it.
And fer chrissakes (and for heaven sakes and for Pete sakes and for your sakes too) do not shine this laser at any vehicle, whether ground-based like a motorcycle, car, or truck, or air-based like a helicopter, airplane, or jet. And if you shoot it at a person in the dark and he turns out to be a police officer, he may think he's being targeted, unholster (pull out) his gun, and hose you down with it.
This is a CDRH Class IIIb laser device. Treat it with respect, and it'll treat you with respect.

This laser is not water-resistant, so water, milk, diet vanilla Pepsi, cold (or hot) coffee, urine, ice cold fizzy root beer, or other liquids could get inside. So please try not to drop it in creeks, rivers, ponds, lakes, oceansides, docksides, snowbanks, puddles of horse pee, glasses of milk, slush piles, mud puddles, tubs, root beer floats, toilet bowls, cisterns, sinks, cups of coffee (hot *OR* cold), fishtanks, dog water dishes, old yucky wet mops, wall-mounted porcelain urinators, leaky water heaters, busted garden hoses, puddles of antifreeze, brake fluid, tranny fluid, gasoline, or other places where water or water-like liquids might be found. And you'll probably want to cover it up or otherwise get rid of it (such as by putting it in a pocket or bag) if you need to carry it in rainy or snowy weather.

Since this is a high powered laser, I would recommend a duty cycle of no longer than 37.5%. That is, 30 seconds on, and at least one minute off to allow the "guts" inside to cool down. This is not stated anywhere, but is my own recommendation.

There *IS* a label on the laser stating that it has a maximum output of 240mW at 532nm, but there is no mention of it's CDRH (Center for Devices and Radiological Health) rating - no mention of CDRH anywhere on the label for that matter. The label looks official, but from what I can tell, it is not.

I figured the 240mW rating was largely infrared, but spectroscopy showed surprisingly little IR radiation.
What I believe has occurred is that the seller read the label and stated "240mW" without using the word "max" in his listing.

I don't believe this laser is a "tabby-thrashed segment of a sewer pickle initiator of intercourse with maternal parent" (toylet words replaced with innocous ones - the correct acronym is PWPOSMF), but because of the gross misrepresentation of power output, it won't rate very highly either.

Beam photograph at ~12".
Power output measures 31.59mW using the IR filter from another one of my DPSS lasers.

Beam is not white like this photograph makes it appear.
Beam spot is significantly smaller than it appears; the beam image bloomed.

Photograph of the beam spot on a wall at ~10'.
Beam is not white like this photograph makes it appear.

Beam is smaller than it appears;
the beam image also bloomed when photographed.
And those artifacts around and toward the upper right of the beam spot in this photograph do not really exist.

Those rectangular graphic things in the upper left quadrant of this photograph are marquees from:
Nintendo ''R-Type''
Super Tiger...er...uh...Konami ''Super Cobra''
Midway ''Omega Race''
Sega ''Star Trek''
Williams ''Joust''
Venture Line ''Looping''
Universal ''Mr. Do!'s Castle''
Jaleco ''Exerion''
Gremlin/Sega ''Astro Blaster''
Atari ''Tempest''
Gottlieb ''Q*bert''

upright coin-op arcade video games from the 1980s.

Photograph of the beams of this laser and a PGL-IIIA laser on a ceiling.
Photoflash was used.
This laser is on the left, a PGL-IIIA laser is on the right. Beams are not white like this photograph makes them appear.

Spectrographic analysis
Spectrographic analysis of this laser.

Spectrographic analysis
Same as above; newer software & settings used.

Spectrographic analysis
Same as above; newer software & settings used. Spectrometer deliberately "overloaded" to show NIR emission.
USB2000 spectrometer graciously donated by P.L.

ProMetric analysis
Beam cross-sectional analysis.
Image made using the ProMetric System by Radiant Imaging.

Video clip on YourTube showing what an airline pilot or copilot might see if you attempted to hose down the approaching aircraft with a laser pointer from a mile or two out.

Taken with a Canon Powershot G3 Digital Camera.

Three laser wavelengths were used here:
532nm green.
440nm royal blue.
405nm violet
(the person being irradiated would see this as a deep violet color; not bluish as this video indicates. This is because digital cameras have a tough go of it at wavelengths this short).

This clip is approximately 6.777566392340 megabytes (6,983,706 bytes) in length; dial-up users please be aware.
It will take no less than thirty three minutes to load at 48.0Kbps.

This clip is approximately 10.000084561256 megabytes (10,167,992 bytes) in length; dial-up users please be aware.
It will take no less than fifty minutes to load at 48.0Kbps.

Same thing as above; shot with the Polaroid x530 Digital Camera this time.

I do not have an outdoor laser testing facility at my new location,
so I will not be able to provide any distance photographs.

Test unit was purchased on Ebay on 05-18-07, and was received on the afternoon of 05-25-07.

Product was *VERY LIKELY* made in China. A product's country of origin really does matter to some people, which is why I published it on this web page.

UPDATE 01-20-11:
I have given this laser to J.R. in Arizona USA (we were roommates at The Juneau Receiving Home from the late-1970s through the early-1980s and I hadn't heard from him until 12-17-10 {or "17 Dec. 2010" if you prefer}), so that dreadful "" icon will be apppended to its listings on this website, denoting the fact that I no longer have it at my disposal for additional comparisons or analyses.

Very bright green laser beam.
Feels good in the hand; is also rather hefty.
No beam artifacts - none that I've been able to detect anyway.
Uses batteries that are relatively inexpensive and readily available.

CDRH label appears to be a phoney
Does ***NOT*** output 240mW - more like ~31.6mW; advertised power output is grossly misrepresented
Fragile interior construction - like all DPSS lasers. Will not figure into my rating
Not water-resistant - but most other DPSS lasers aren't either. Will not figure into my rating

    PRODUCT TYPE: Pen-style laser module
    LAMP TYPE: DPSS diode laser/NdYVO4/KTP crystals
    No. OF LAMPS: 1
    BEAM TYPE: Very narrow; it's a laser, remember? ;-)
    SWITCH TYPE: Pushbutton momentary on/off on barrel
    BEZEL: Metal; has aperture (hole) for laser beam to emerge
    BATTERY: 2xAAA cells
    WARRANTY: Unknown/not stated


    Star Rating

240mW Green Laser Pen *

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