Snapshots of ephemeral events that fingerprint different biological phenomena are within reach thanks to the generation of ultrashort bursts of light produced by attosecond (10-18 seconds) lasers. At a cutting-edge laser laboratory in Saudi Arabia, the properties of light will be pushed to this extreme in the analysis of protein and nucleic acids in blood samples from cancer patients and in other studies.1 Since the United Nations has designated 2015 as the Year of Light and Light-based Technologies, it is worthwhile remembering the pioneers that enabled the development of light-based technologies ranging from the bulb to the attosecond laser. In a Nature commemorative issue, Prof. Khalili (University of Surrey in Guildford, UK) revisits the major contributions to optical principles made by Iraqi-born mathematician and astronomer, Abū ʿAlī al-Ḥasan ibn al-Haytham (Ibn al-Haytham; born c. 965, Basra, Iraq—died c. 1040, Cairo, Egypt). Imprisoned by a Fatimid caliph, ibn al-Haytham used the time to think and write, particularly about optics. Following his release, he combined this writing with experimental observations in his seminal seven-volume Book of Optics (Kitāb al-manāẓir).2 The book contains the correct model of vision, a complete formulation of the laws of reflection, and a detailed investigation of refraction. In addition, he published other studies on optics, including Ḍawʾ al-qamar (“On the Light of the Moon”), al-Hāla wa-qaws quzaḥ (“On the Halo and the Rainbow”), Ṣūrat al-kusūf (“On the Shape of the Eclipse”; which includes a discussion of the camera obscura), and al-Ḍawʾ (“A Discourse on Light”). Interestingly, it is speculated that the 17th century Dutch master, Vermeer, may have used a camera obscura – the precursor to the camera and photography – in achieving exquisite detail in his paintings. Other polymaths and artists such as Leonardo Da Vinci and Piero della Francesca have applied his discoveries to create the illusion of three-dimensional depth on canvas and in friezes.2 Together with his accomplishments in mathematics and astronomy, Ibn al-Haytham has influenced seventeenth-century European scientists such as Johannes Kepler and enhanced our present understanding of classical optics.
1 Abbott, A. Nature 518, 281-2, 2015
2 Al-Khalili, J. Nature 518, 164-5, 2015