Three main types of lasers are best for removing tattoos: the neodymium, yttrium aluminum garnet laser (Nd:YAG), the alexandrite laser, and the ruby laser.

These lasers are named by the type of crystal that is used to generate the laser light/energy (laser folks call it energy if we can’t see it and light if we can). An energy source which is usually a bright strobe light, but can also be another inexpensive (diode) type of laser is used to ‘pump’ energy into a laser cavity containing the rod made of one of the above 3 materials.

Nd:YAG Laser

The Nd:YAG laser puts out invisible light that is 1,064 nm in wavelength; it’s infrared, which means if we could see it, it would be a deep red. Nd:YAG lasers incorporate a potassium titanyl phosphate (KTP) crystal that doubles the frequency, thus cutting the wavelength in half. All this means is that Nd:YAG lasers can put out 2 wavelengths of light, infrared 1,064 nm light and green 532 nm light. This is important because the infrared light is used to remove black tattoos, while the green light is used to remove red tattoos. A simple way to think about that is illustrated by looking at a plant. Plants’ leaves are typically green, so they are reflecting green light at our eyes. This means that plants don’t need that color of green light for photosynthesis or anything else-they reflect it away at our eyes. To remove a tattoo, laser light has to be taken up by the tattoo, a red tattoo reflects red light away at our eyes, so we can’t use it to remove red tattoos-we need green light for that.

Alexandrite Laser

Another type of laser that is commonly used to remove tattoos is the alexandrite laser. An alexandrite is a very expensive deep red gemstone.  The alexandrite rods used in lasers are synthetic versions of these crystals, and produce a deep red light. Alexandrite laser light is particularly effective at removing green, blue and purple tattoos.

Ruby Lasers

Ruby lasers use a synthetic ruby crystal to generate red light, and are quite effective at removing black ink, with some effectiveness on green, blue and purple ink.