The Visible Spectrum and Human Eye Sensitivity

The human eye can detect the light colors from about 400 nanometers (violet) to about 700 nanometers (red) (see color chart).

A 405nm LASER is just into the visible range below Ultraviolet, and 45 nanometers below that¹ is the Cobalt Series LASERS.

This chart illustrates the eye's sensitivity to the various colors (frequencies) in the visual range. You will note that the peak of the eye's sensitivity is at around 520 to 550 nanometers – which is why a 532nm GREEN LASER is an ideal choice for sky-pointing, and why this color is also most distracting to airplane pilots if some idiot below fires a LASER at the cockpit. The human eye is LEAST sensitive to blue / violet at the higher frequency (lower wavelength) and at red / infrared at the lower frequency (higher wavelength). {Each horizontal line on the chart is 25%, vertical lines are 50nm}.

The implication here is simple: If the eye is INSENSITIVE to the color you're looking at, and the light is extremely bright, then what you are looking at is orders of magnitude more powerful.

          Look at the chart (above) again. At the 445nm (blue) wavelength, the eye is approximately at 20% of its sensitivity. At the 532nm (green) frequency, the eye is nearly at 100% of its sensitivity. In short, what you SEE when you look at the beam of the Cobalt Series LASERS is impressive, but what you SEE is only 1/5^th of what is actually present in terms of output power, as opposed to looking at a green LASER.

          In addition, these LASER'S beam diameters at the aperture is a tiny 0.25mm³ and divergence is less than 0.9mRad (This means the beam expands by 0.9mm / meter see Wikipedia). If a LASER beam diameter is small, it can go further and impart more energy to a target than if the diameter is big. Ideally, we want to have small beam diameter at aperture AND small beam divergence. Cobalt Series LASERS meet both of those criteria.

          Because of its awesome power, small beam diameter, and small beam divergence, the Cobalt Series LASERS can be hazardous at very long distances.

          We do not suggest that these LASERS be used for "Sky Pointing". A red LASER – at any available power, is useless for sky pointing, because the beam is almost impossible to see – even in pitch black darkness.

          Although the beam on the Cobalt Series LASERS is very visible, and could be used for 'sky pointing', it is not recommended for several reasons, not the least of which is that the beam will travel much further than your eye can see, and if you accidentally happen to hit an aircraft's cockpit, the beam is so powerful that you will cause a distraction and momentary 'flash' blindness much more than the high-power green LASERS are capable of doing. The beams of these LASERS reach much farther than you can see with the unaided eye.

        LASER Enthusiasts, like Amateur (Ham) radio operators⁴ (or Doctor Frankenstein) are pioneers and developers – not little kids playing with their Sci-fi 'toys'. The next big breakthroughs in science may indeed come from the growing community of intelligent and responsible Enthusiasts, Hobbyists, and Researchers working and playing around in this field. Some LASER Owners⁵ have gotten themselves lengthy prison terms (and new hobbies) by targeting aircraft – even with PUNY LASERS (see videos).

        LASER Enthusiasts do not allow LASER Owners to 'skypoint' aircraft or other moving vehicles. What can YOU do if you see someone doing this? See FAQs

        LASER Enthusiasts are responsible individuals who take pride their hobby, seek to protect it from litigation brought on by idiots who use them to commit crimes. Enthusiasts exercise responsibility in the legitimate, lawful, and safe operation of LASERS.

FOOTNOTES

1 Below that – Lower Frequency, Longer Wavelength.

2 LASER Enthusiast – someone whose hobby is experimenting with LASERS.

3 Typical beam diameter at aperture for a hand-held LASER is 0.3mm.

4 My Amateur Radio Call Sign is WB2-ANR ("Whiskey Bravo Two - Always Needs Repair)

5 LASER Owner as opposed to Enthusiast; an owner is not an enthusiast by virtue of ownership.