On 20 December 2013,the UN General Assembly 68 th Session proclaimed 2015 as the International Year of Light and Light-based Technologies(IYL 2015).Based on the anniversaries of a series of important milestones in the history of the science of light which held in International Year of Light,this paper makes a survey of light science in the last millennium.Apart from providing a comprehensive list of important events,this paper also gives an overview of optics from a physics perspective of observation.Three ...