In the movies, when a law enforcement or super villain henchmen aims a gun at the hero, you immediately know it because of the bright red point of the laser sight on the gun. Of course, this event generally happens at night since red laser sights are difficult to see in the daylight. Recently though, I was given the opportunity to examine several different types of laser sights and one that I came across intrigued me. The laser was green. This made me wonder, what is the difference between green and red laser sights? Which is better? Which is easier to see in different situations?
Red lasers are made with a diode, optics, and a minimal amount of electronics. In fact, they are so simple that Instructables’ website has directions to make them in less than ten steps. The simplicity and commonality of the ingredients make red lasers cheap and easy to manufacture. According to scientists, “The difference between a red laser and a green laser light is that the red laser light has a longer wavelength (about 650 nanometers) than does the green (about 532 nanometers).” On the other hand, green lasers are more expensive because they require a special diode that is rarer, a frequency-doubling crystal, and a second infrared laser crystal. All of these must be perfectly aligned in order for the laser to function correctly.
So green lasers are more complicated and costly than red lasers, but does that mean they perform better? You might think that the two lasers are basically the same, but this is not the case. Green light bends more than red light when it enters a glass lens, so a green laser sight will look slightly different than a red laser light. The strongest argument for using a green laser light is visibility; green light is more visible to the naked eye than red light because green is closer to the center of the visible spectrum. “As many know, laser sights can be very beneficial; but there is one major flaw… ordinary red lasers can be next to impossible to see in most daylight conditions. The benefit of a green laser is that it is much more visible, allowing for it to be used anytime, day or night, indoors or outdoors, permitting you to track your target quicker and more accurately. Additionally…you can actually see a very intimidating visible beam in low-light conditions.” What a great gift idea for the gun enthusiast!