The diode laser has a longer wavelength than the Alexandrite and Ruby lasers. (Ruby laser is a red-colored beam of light used to strike the dark melanin, which is a biological pigment, present in the hair follicles.) Hence, diode is able to penetrate deeper into the skin, allowing treatment on dark-skinned people, unlike the other two lasers.
Yet, the diode doesn’t promise desired results for the dark-skinned people. However, for people with dark, coarse hair, diode laser hair removal is a boon. And it is particularly effective over large areas of the body such as back and chest. So, all you men out there, if you want to get rid of the ugly hair on your chest and back, diode laser hair removal is for you.