Light is simply a small part of the Electromagnetic Spectrum. Below is an explanation of the spectrum
The nm is the wavelength of light, nm = nanometer. Actually "light" is an electromagnetic wave. The entire electromagnetic spectrum ranges from radio waves, which have the longest wavelength to gamma waves, which have the shortest wavelength. Basically all of these waves are the same type of wave, travel at the same speed (speed of light), but have different wavelengths. Visible light makes up only a tiny part of the Electromagnetic Spectrum.
All the waves travel at the same speed, therefore the smaller the wavelength, the more waves per second (frequency). The higher frequency wave have more energy and can do more damage. The spectrum goes basically like this: Starting with the longest wavelength (lowest frequency)...Radio Waves---Micro Waves---Infrared Waves---Visible Light(red-orange-yellow-green-blue-indigo-violet)---Ultra-Violet Waves---X-Ray Waves---Gamma Waves, which have the smallest wavelength (highest frequency). So light is made up of the same "stuff" as all of the waves listed.
The color of the lasers are 650nm & 635nm = red light 532nm = green light 445 = blue light 405nm = purple light.