Q & A / FAQs on handheld LASEZRS

A. Yes. The LASERS are legal to own, however, using them to endanger aircraft or moving vehicles is a crime (see NEWS reports of such abuse). Under the USA Patriot Act, it is conceivable that incidents involving aircraft could be prosecuted as TERRORISM, and you could end up being held incommunicado and water-boarded at Gitmo. US Commercial aircraft employ sensors that warn of LASER radiation, and the GPS coordinates of the originating beam are instantly calculated and reported to to FAA and NORAD. Shining a LASER at an aircraft is SERIOUS business, and treated as a "targeting lock-on", just as if you aimed a Stinger missile.

A. We send you this LASER warning poster with your order of a 200mw or higher power LASER.

A. In responsible hands, they are no more "dangerous" than very bright flashlights. Staring into the beam of either a LASER or a 1,000 Watt Klieg lamp will most likely cause temporary "spot blindness" but to permanently damage your retina would probably be unlikely at any appreciable distance because a light this bright will cause involuntary aversion reaction. This is the reason that shining a LASER at an aircraft or moving vehicle is illegal. Looking into a LASER beam of a 200mw or higher power LASER at close range is definitely NOT recommended.

A. Two characteristics of LASER light contribute to the hazard of handheld LASERS:

Q. Do high-power "astronomy" LASERS such as these pose a danger to eyesight?
A. Yes, definitely. At close range, even a sweeping LASER crossing your retina can cause irreparable eye damage. The risk of damage is less, but still significant when the beam is reflected. The risk becomes less pronounced with distance from the aperture because of the beam divergence. Some of the high-power units available employ safety keys which must be inserted into the back-end of the LASER in order to operate it. This keeps children from using these units, and ensures that the operator points the LASER away from himself when the key is inserted.

A. Primarily, they are used for "sky-pointing" - or for aiming telescopes without using the rangefinder scope. Other uses include holography, firearms target training, construction (leveling and spotting), and by law enforcement for forensics use in determining the path and ricochet patterns of bullets. In the woods, you can carry one of these to signal for help in case you get lost or injured. A high-power LASER can be used to illuminate a space where a flashlight could never reach - such as into a cave or down a deep well. A high-power LASER shone into a copper pipe would reflect even around bends in the pipe to test for obstructions. Two or more LASERS aimed at the same spot using a compass or sextant can be used to triangulate the position of a target (such as a campfire) on a map. The 30mw units can be mounted on rifles with a modified Weaver mount. High-power INFRARED LASERS are used by the military to "paint" targets in order to guide precision air strikes to targets on the ground. Also see: LASER info.

A. Because they're ripping people off. We'll put our LASERS up against theirs any day!

A. For maximum performance, (non-rechargeable) LITHIUM batteries will produce the most output and last the longest. However, these are quite expensive. Using standard Carbon batteries is NOT recommended. You can also use NiCd or NiMh rechargeable batteries which are 1.2 Volts, but this will reduce the power output by approximately 20 percent. NiMh rechargeable batteries are best suited for general use, since the power output remains stable for about 80% to 90% of the usable charge, and NiMh batteries do not suffer from the ":memory effect" that NiCd batteries exhibit. Suitable batteries can be purchased at great prices on ebay. Save even MORE money on all your online purchases (including eBay and hundreds of other stores) by signing up here: Save Money on Your Online Purchases

A. At ground level with no obstructions (such as buildings or trees) these LASERS can be clearly seen 21 miles away (the horizon at sea level is 22 miles). If you are on a ship or sailboat, you can point one of these LASERS at a ship on the horizon, and they will be able to see it clearly. Light travels in a straight line; it won't bend around the curvature of the Earth, and that is why claims of "100-mile visibility" are total B.S. (see below).

A. The Star Cap is a screw-on accessory that mounts on the LASER aperture. Essentially, it is a beam splitter used to create kaleidoscope effects. When attached to the LASER, the Star Cap can be rotated (manually) to create a mesmerizing pattern of dots. Great for those boring movie theatre intermissions.

Q. One of your competitor's Web sites states that their LASERS can be seen for 100 miles. Are their LASERS more powerful or better than yours?

A. This claim is pure horse-hockey. There is no place on the surface of planet Earth where one could actually test this ridiculous claim.... unless the participants of this test were in ORBIT, and shining LASER beams between Space Shuttles. I defy them to name any place on the surface of the Earth where line-of-sight visibility is "100 miles". However, on a clear night, a 200 or 300 mw LASER aimed from Earth would be clearly visible to an astronaut standing on the moon. It would also be visible to visiting aliens, and could possibly be construed as an invitation for a "close encounter of the fourth kind". If you get abducted, you can't say you weren't warned. (ROTFL).

A. All the LASERS we sell on this site can be held "on" continuously, although why you would want to is beyond me. The LASER head will become warm to the touch, which is normal. There is ample heat-sinking of the DPSS diodes in all of our LASERS to keep the diode cool until the batteries die.

A. MTBF (Mean Time Between Failure) of a typical DPSS LASER diode is approximately 8,000 to 10,000 hours. At this rate, it amounts to between 333 to 416 (24-hour) days of continuous "on"-time. Unless you have the thing surgically implanted in your skull like the Borg on Star Trek, these LASER pointers will last a lifetime with normal use, and can probably be left to your children in your will.

A. 100 milliwatts. ;-) Seriously - A 300mw LASER will be approximately 1/3 again as bright as a 200mw unit. LASER "radiation" is LIGHT - and (normal) light, like radio waves, follows the inverse-square law. For example, if a 4-watt radio transmitter such as a Citizen's Band walkie-talkie has a range of 20 miles, if you wanted to DOUBLE the range, you would have to square the power: i.e.: (4²) = 16 Watts. However, highly monochromatic (single-color) LASER light does not follow the inverse-square law. If you had a LASER with a ZERO-degree beam divergence - in other words, the beam diameter remained the same no matter what the distance, the power would be the same at 100 miles from the source as it is 2 feet from the source (ignoring atmospheric scattering and absorption). A zero degree beam divergence is impossible, and so the amount of power imparted to the target is mainly a factor of A) How much power there is to start with, and B) How big the "dot" gets as a function of distance from the LASER aperture. As the diameter of the dot increases, the power of the LASER is distributed over the area of the dot, and is a function of pi.

A. LASER light beams are subject to divergence, which is measured in milliradians (mrad) or degrees. For many applications, a lower-divergence beam is preferable. Neglecting divergence due to poor beam quality, the divergence of a LASER beam is proportional to its wavelength and inversely proportional to the diameter of the beam at its narrowest point. For example, an ultraviolet LASER that emits at a wavelength of 308 nM will have a lower divergence than an infrared LASER at 808 nM, if both have the same minimum beam diameter. The divergence of good-quality LASER beams is modeled using the mathematics of Gaussian beams. LASERS used for astronomy purposes ("sky-pointing") are designed so that the beam is visible to the naked eye located at the source of the beam for approximately 1 mile. After the beam has traveled a mile into the sky, to the user, it seems to end abruptly. This is the point where the human eye's resolution can no longer resolve the beam; in effect, it "disappears". However, an observer in an airplane flying at 5,000 feet would see the beam for (another) mile into the sky from his position.

If the beam divergence was too wide, the beam would get fatter (and the "dot" bigger) very fast, and the LASER would be useless for sky-pointing. If the divergence angle were too narrow, the beam would cease to be visible to the user at a very short distance, again making it useless for sky-pointing. The mark of a great sky-pointing LASER is one whose beam diameter seems to remain constant to the observer as it travels away from the LASER.

This photo of our 300mw Green LASER shows the ideal beam divergence configuration for a sky-pointing LASER. Notice that the diameter of the beam does not appear to change as it moves away from the user. In actuality, the beam is spreading out ever so slightly - just enough to keep it visible from the user's perspective, until the eye can no longer see it. The beam seems a bit wider at the source in the center photo because its brightness is overwhelming the CCD in the digital camera. There isn't a better LASER for sky-pointing available anywhere, at any price.

A. Yes. Due to the sensitivity curve of the human eye, a wavelength of 635 nM appears at least 4 times brighter than an equivalent power level at 670 nM. Thus, shorter wavelength LASERS will be best where maximum visibility is important. A Green (532nm) LASER is the most visible as a function of power vs. wavelength. The lower the (nanoMeter) number (nM) the shorter the wavelength. For those who want the technicalities, here they are:

Q. The LASER in your sky photos seems to end abruptly in the sky. Why is that?

A. The beam doesn't end; it's just that your eye cannot resolve the narrow beam from that distance. At the point where the diameter of the beam becomes too small to see with the naked eye, it SEEMS to abruptly end. This is partly due to a phenomenon called "scotopic vision". Imagine a Dayglo™ thread stretched from the Earth to the moon. Even though this theoretical thread would actually reach the moon's surface, at what point would the thread extending into the sky NOT be visible to your naked eye? Same with the LASER beam. This "abrupt end" phenomenon is an illusion - caused by the limited resolution of the human eye. Another factor is atmospheric dust and humidity. As the beam travels further up into the atmosphere, reduced humidity and airborne particulates reduces the amount of reflection, and the beam will fade abruptly. If you have a LASER that "fades" or gets dimmer as it travels short distances, it is because the beam divergence angle is too high - A high beam divergence angle is the mark of a cheap piece of junk - at least as far as sky-pointing purposes are concerned.

Q. On some nights the beam from my 30mw Green LASER is clearly visible, and on other nights it seems much dimmer. I'm using fresh batteries each time. Is something wrong with the LASER?

A. Probably not. The reason you can see the beam AT ALL is because of atmospheric humidity and dust particles. Part of the beam gets reflected off of microscopic water droplets and dust, (Rayleigh scattering) and you see this as a thin beam. When there is very little humidity and very little dust such as on a crisp winter night, the beam will not seem as bright. And - by the way... If you took your LASER pointer onto the space Station, went EVA and aimed it out into space, you (as an observer) would not see the beam at all.

Q. The 300mw LASER I got from you takes a second to come up to full power with fresh batteries. Is it defective?

A. No. The "warm-up" time is due to the fact that the diode in the LASER is not being driven to its full-rated power. The diode in your unit #300LSKG is rated at 2 Watts (2,000mW) and so it takes a bit to "warm-up". The particularly cold weather may also be affecting the diode's ability to reach optimum temperature. I suggest you keep the unit in a breast pocket under your jacket - to keep it "cozy" until you need to use it.

Q. How efficient are Green, Blue, and Yellow DPSS LASERS and why does efficiency matter?

A. Green DPSS LASERs are usually around 20% efficient, although some LASERs have been reported to be 35% efficient. In other words, a green DPSS LASER using a 2.5 W pump diode would be expected to output around 500 mW of 532 nM light.

Blue DPSS LASERs use an extremely similar process, except that the 808 nM light is being converted to 946 nM light, which is then frequency-doubled to 473 nM. Because of the lower gain for the materials, blue LASERs are relatively weak, and are only around 3% efficient.

Yellow LASERs use an even more complicated process. A 808 nM pump is used to generate 1,064 nM and 1,342 nM light, which is summed to become 593.5 nM. Yellow LASERs are about as efficient as blue LASERs, but due to their complexity and costs, most yellow DPSS LASERs are only around 1% efficient.

A. Efficiency matters in LASER pointers because of the power consumption required to power a hand-held device. The higher the efficiency, the less the power drain on the batteries in order to gain the same output power. Green LASERS are most efficient among the various colors available, and since the human eye is particularly sensitive at the Green wavelength, a Green LASER will appear significantly brighter than a Blue, Red, or Yellow LASER with the same output power. However, the power (heat) imparted to a non-reflecting (black) object will be approximately the same.

Q. When I keep my LASER on for a minute, the spot gets distorted and spreads out. Is my unit defective?

A. No, probably not. What is happening is that the batteries you are using are probably weak or defective. The LASER consumes a lot of current which causes a drop in the output voltage. When the supplied voltage drops below the minimum voltage specification, a DPSS LASER diode will oscillate, and what you will see is an elongated dot which slowly spreads into a herringbone line. Change / charge the batteries.

Q. When you say the the 300mW lasers were failing to fire at low temperatures, what did you mean by low temperatures? 60° F, or 30° F or -20° F?

A. ONLY the BLUE LASERS were 'failing' - we had a few returned because customers in Buffalo NY were taking them outside where it was close to -10°F and they failed to laze. We spoke with the mad scientist who puts them together, and he says DPSS LASERS - especially the BLUE ones, because the diodes in these LASERs are UNDER-driven (so they can fire continuously without burning up) will take a while to warm up. They didn't FAIL; they just needed time to come up to operating temperature.

The optics in these units are very precise. Contraction of the metal lens mounts and diode heat sinks misalign - or more precisely, cause the spacing between the diode and the mirror to get closer, and the diode fires, but the reflection from the mirror gets out of phase - just like a WARP CORE or a di-lithium crystal, and it has to 'warm up' in order to work. The BLUE ones are more susceptible, because they have MULTIPLE sets of mirrors, which are 'sandwiched' together in a single 'chip'. If the chip gets cold and contracts, the layers move closer together, and create moiré patterns (which is interesting), then they 'fail' altogether. We tested this temperature sensitivity on our GREEN LASERS, and if they're cold - they will take a second or two to 'warm up' as well. In all cases, when the temperature returns to a reasonable value - to where a HUMAN BEING would be comfortable, performance returns to normal.

I am told that if a LASER instrument does NOT exhibit this sensitivity, the components are NOT adequately heat-sinked - you can't mount the optics in rubber 'shock mounts' and expect them to stay aligned. The down-side is that if you precision mount a diode and lens in a brass / aluminum housing, you can THEN shock-mount the entire assembly. When you do that, there is still metal and optics in direct contact, and if the unit is subjected to high-G forces (such as being dropped) the metal around the optics will STILL impart some force to the components, and if the force is great enough, the components will be damaged.

Take heart, however. I've had several of these units for about a year now. All of them work flawlessly. I dropped my GREEN 300mw unit down a flight of stairs once. I was sure I'd have a door-stop on my hands, but by some miracle, it still works (I can't guarantee any of these units will survive being dropped down a flight of stairs).

Cheap, non-DPSS LASERS do NOT have any external optics (outside the diode). For example, you can throw a $4.00 5mw RED LASER pen out of a car going 60MPH, pick it up, put batteries in it, and it will still work. Once you add components OUTSIDE the LASER diode, such as an infrared filter (by US law, all LASERS over 5mw sold in the US must have infrared filters to be legally sold), collimator lens (all our LASERS have these), you are dealing with DELICATE PRECISION INSTRUMENTS that are intolerant of abuse.

The diodes in OUR 300mw LASERS are rated at 2 Watts (2,000 mw). The metal around them is MASSIVE. This enables you to fire them continuously until the battery dies, without harm to the diode or the surrounding optics. However, the metal has weight and has delicate parts around it. It is shock-mounted, but a drop from 6 feet onto a concrete floor may crack the reflector mirror and destroy the ability to lase, but the diode will still work - but it costs more to fix it than to replace it. This is true of all precision optical instruments.

In order for the convection of heat to flow from ceramic or glass to metal, there has to be some sort of intermediary heat carrier such as 'heat sink grease' like the white 'lithium' stuff that is used between CPU chips and their heat sinks on PCs. The problem with this is that you cannot use any type of 'grease' on optics. The alternative is to make a very precise fit between the optical components and the surrounding metal. If the surfaces are OPTICALLY smooth, heat transfer will be efficient. Also, having enough metal around the 'hot' components for the heat to dissipate into, helps the components to radiate heat away.

Just be aware that the beam on a BLUE LASER will not stand out in the sky like a green LASER will. The spot will appear light blue to dark purple depending upon the color of the surface it is pointed at. Ifg you are using it for astronomy purposes, a 200mw GREEN PEN-style LASER or a 300mw GREEN FLASHLIGHT-style LASER is the way to go.

A. Whatever toots your horn. You'll need a custom-made mount. Check the laws in your State to see if hunting at night with LASER sights are permitted. BTW if deer are mesmerized by car headlights, I can't imagine how Bambi would react to a LASER pointed at her!

Q. How much power would it take to punch a hole in a piece of aluminum foil?

A. A Lot - probably 100 Watts (100,000 mW) or more. A LASER's light can only punch a hole in something if the "something" doesn't reflect the light. Since a majority of the light hitting a piece of aluminum foil would be reflected and scattered, the little bit that was left would have to provide the "heat" - and aluminum is a great heat dissipater.

A. Yes... of course... but NOT with OURS (unless you buy a whole bunch of them, shoot them off simultaneously, and aim them at the same exact spot). The US Military can zap you with LASERS mounted on orbiting satellites - they cover it up by calling it "spontaneous human combustion" and leaking the story to The National Enquirer (lol).

Q. I've seen magazine ads that advertise plans to build a LASER ray gun. Is this possible?
A. Sure. And if sparrows had banjos for suppositories, there would be music in the air. You can build a LASER pointer with a LASER diode scrounged from a DVD burner and other components from Radio Shack and Home Depot. The project - if successful, will cost you TWICE what it costs to buy one here... If the diode isn't heat-sinked properly it will go up in smoke after a few minutes of continuous use... and as far as "ray guns" in the sense that they can vaporize things like a Klingon disruptor - NOT A CHANCE!

Q. My cat chases the LASER spot - it drives her nuts... but my dog ignores it. What's up?

A. Why are you teasing your cat? Could it be that Dogs are color blind, but cats are not? Your guess is as good as mine. It could be that your cat has nothing better to do than chase light spots on the wall, and your dog has better things to do than chase phantoms so-to-speak.... then again, when was the last time your dog played with a ball of wool or got twisted sniffing catnip? Sounds like a good research project worthy of Federal grant money - hell... the Government researches cow farts and calls it "greenhouse gas" while Al Gore is getting filthy rich selling "Carbon Credits" (maybe farmers will start feeding Bean-o™ to their livestock) - And why not a Federal grant for Ophthalmology studies on two of Man's best friends? Since I suggested it, where's MY "cut"?

Green LASER hits plane landing in Spokane