Wavelengths, Colors The wavelength of laser sources defines its output color. By combining laser sources of different wavelengths it is possible to create color blending and even white laser light.The human eye perceives different wavelengths at different intensities: green is very visible, but blue and red not that much (only about 1/3 of green). The white balance of an RGB whitelight laser systems depends on the power values per color source, so the power per source specifies the color temperature of the output.