The year 2015 was designated by the United Nations General Assembly as the Year of Light and Light-based Technologies, and also marks the anniversaries of a number of significant historical events related to light. In 1015, Ibn Al-Haytham published his book of optics in 1815, Fresnel first proposed the notion that light is actually a wave James Clerk Maxwell then firmly established this concept with his electromagnetic theory of light propagation and Einstein announced his discovery of the photoelectric effect, demonstrating that light is made of photons in 1905, followed in 1915 by his general theory of relativity, Skryť popis