How Lasers Work How Lasers Work Laser light has several features that are significantly different from white light. To begin with, light from most sources spreads out as it travels, so that much less light hits a given area as the distance from the light source increases. Laser light travels as a parallel beam and spreads very little. Furthermore, laser light is monochromatic and coherent.
White light is a jumble of colored light waves.
Each color has a different wavelength. If all the wavelengths but one are filtered out, the remaining light is monochromatic. In the case of laser light, the wave crests coincide and the troughs coincide. The waves all reinforce one another. It is the monochromaticity and coherency of laser light that makes it ideal for recording data on optical media such as a CD as well as use as a light source for long haul fiber-optic communications.