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What is the Difference Between Green and Red Lasers?

What is the Difference Between Green and Red Lasers?

This most obvious difference between green and red lasers is the wavelength of the beam. Green lasers have a wavelength between 560nm and 490nm with 532nm being the wavelength used for almost every laser. Some green lasers will have a wavelength of 526.5nm and green lasers can be made with other wavelengths such as 515nm, 523.5nm and 543nm. The wavelength for red lasers ranges from 700nm to 630nm with the most common wavelengths being 635nm, 655nm and 671nm.

The process used to create the laser beam in green lasers is very different from the process in red lasers. Red lasers are the simplest and the laser module (the section producing the beam) is just a diode and a lens. Green lasers on the other hand are much more complex and use a diode and a series of crystals and lens in a process called frequency doubling to produce a green beam.

In a red laser, the laser diode gives out red light. There are no commonly available diodes that give out green light so green lasers use a diode that gives out 808nm light. The 808nm is then converted to 1064nm by a crystal. The 1064nm light is then changed again, this time to 532nm.

The human eye is much more sensitive to green light than red light with estimates on sensitivity ranging from 10 times more sensitive to 50 times more sensitive. The higher sensitivity of the human eye to green means that green lasers are much brighter than red lasers and more suitable than red lasers for many applications such as pointing, alignment and astronomy. Green is normally the color of choice for general purpose lasers with red normally only used for research, laser shows and specific industrial applications.

Colored lasers, often called RGB lasers, are made using a blue laser, a red laser and a green laser. Due to the different brightness of red lasers to green lasers and even blue lasers, different ratios of power are need for red, blue and green are to produce a balanced white light. Using 635nm red light, the common power ratio for the three different colors is 3 red to 2 blue to 1 green.

Green and red laser light have different physical properties which not only effects their application, the different also effects the laser safety glasses that are worn. The laser safety glasses that protect against green laser beams are different from the laser safety glasses that protect against red laser beams. It is critical to the safety of your eyes to make sure that the laser safety glasses you wear match the color of the laser you are using.

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