The entire physical universe is made up of pure energy and vibration. When you have the insight to see everything as vibration, the nature of the universe is revealed to you. Light is vibration. The entire electromagnetic wave spectrum of visible light produces different colors.
Colors are simply waves vibrating at different frequencies. On one end of the spectrum you have red, on the other end you have violet. Red has the longest wavelength and the lowest frequency, violet has the shortest wavelength and the highest frequency.