UN General Assembly 68th Session proclaimed 2015 as the International Year of Light and Light-based Technologies (IYL 2015). The resolution noted that this year is an anniversary for a number of important events in the history of the science of light.
ITMO is proud to participate in the celebration of the International Year of Light 2015, promoting the advancement of Knowledge about light, optics and light-based technologies, inspiring future generations to careers in these fields, and contributing to international cooperation and understanding through Light.Read more
Ibn al-Haytham writes his works on optics
Ibn al-Haytham put forward his theory that the "natural light and colored rays affect the eye" and "a visual image is obtained by means of rays that are emitted by visible bodies and get to the eyes." Thus, in VI BC. (i.e. 17 centuries before al-Haytham) Pythagoras expressed exactly the same (close to the present one) idea that objects become visible due to the particles emitted by them.
Al-Haytham believed that each point of the observed object could be associated with a perceiving point of the eye. He also gave a correct definition of binocular vision and made an assumption of the finite speed of light.
Augustin Fresnel introduces the concept of a light wave
Augustin Fresnel introduced the concept of a light wave and formulated the principle of interference having done several new experiments that differed from those conducted by Thomas Young (in particular, the experiment with the "Fresnel double mirror").
Based on this principle, in 1818 Fresnel elaborated the theory of light diffraction. He suggested the method of calculation of the diffraction pattern, based on the wave front fragmentation (so-called Fresnel zones). Using this method, he solved the problem of light diffraction on the edge of a semi-screen and circular hole.
James Maxwell creates the theory of light propagation
James Maxwell concluded that magnetism is characterized by vortex lines, while electric current is translational. In the same paper, Maxwell proceeded to the examination of disturbance propagation in his model and noticed the similarity of vortex environment properties and Fresnel’s luminiferous ether. This was reflected in the practical coincidence of the disturbance propagation velocity (the ratio of electromagnetic and electrostatic units of electricity defined by Weber and Rudolf Kohlrausch) and the speed of light, which was measured by Arman Hippolyte Louis Fizeau. Thus, Maxwell made a decisive step toward the construction of the electromagnetic theory of light.
Albert Einstein proposes the theory of the photoelectric effect
Einstein proposed a thesis that not only emission, but also the propagation and absorption of light are discrete; these quanta were subsequently called photons. The thesis allowed the great physicist to explain the two puzzles of the photoelectric effect: why the photocurrent arose not at every frequency of light, but started at a certain threshold depending on the type of metal, and why the energy and speed of the emitted electrons did not depend on the intensity of light but only on its frequency. Einstein's theory of photoelectric effect precisely matched the experimental data that was later confirmed by Robert Millikan’s experiments.
Arno Penzias and Robert Wilson open the cosmic microwave background radiation
In 1965, Arno Penzias and Robert Woodrow Wilson from the Bell Telephone Laboratories in Holmdel (New Jersey) built a device similar to Robert Dicke’s radiometer that they intended to use not to search for relic radiation that Dicke predicted but for experiments in the field of radio astronomy and satellite communications. When calibrating the installation they revealed that the antenna had excess noise temperature of 3.5 K, which they could not explain. After receiving a call from Holmdel, Dicke humorously remarked: “Boys, we've been scooped!” The joint discussion of the Princeton group and the Holmdel group concluded that such temperature of the antenna could only caused by the cosmic microwave background radiation.
Charles Kao reaches incredible success in the field of optical fiber communication based on light transmission
Charles Kao explored the possibility of transmitting information over long distances via optical fiber cables. The main theoretical conclusion of his work was the determination of the threshold value of signal attenuation. He found out that to make the information travel inside the optical fiber channels without significant losses, the attenuation value should not exceed 20 dB/km. This fact spurred researchers to search for materials that are more likely to conform to the established criteria. Thorough testing led to the conclusion that the best candidate for optical communication lines was fused silica (SiO2), which demonstrated the lowest level of signal attenuation.