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Bertolotti M. The history of the laser (IoP, 2005)(316s)_EO_.pdf |
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The rise of modern science A necessary condition for the emergence of modern science was emancipation from the Thomist philosophy. The process was aided by a number of circumstances. During the 15th century, various causes contributed to the decline of the papacy which resulted in a very rapid political and cultural change to society. Gunpowder strengthened central government at the...
Figure 2. Kepler’s laws. (a) The first law states that planets move on elliptic orbits with the Sun at one focus. The perihelion and aphelion are the point of minimum and maximum distance from Sun, respectively. (b) The second law states that the line which connects the Sun to the planet covers equal area in equal times. Therefore, the two shaded areas are equal if to cover each one the same time is employed, and the planet must have higher speed when travelling in the segment nearer to the Sun than when it travels in a more distant segment. The third law establishes that the square of the time a planet employs to make a full trip around the Sun is proportional to the cube of the major semi-axis of its orbit....
The law of refraction In the work Dioptrique, Descartes presents his theory of light based on vortices, and discusses the laws of reflection and refraction, expressing for...
Christiaan Huygens Christiaan Huygens, one of the founders of mechanics and physical optics, was born at Den Hague in 1629. He was a son of Constantijn (1596–1687), a well known poet of the Renaissance. Initially he studied rhetoric and law but, being a lover of sciences, he changed to mathematical studies. In 1655, by means of a powerful homemade telescope, Huygens clarified the problem of the configuration of Saturn by discovering its rings. He also 15
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Isaac Newton Isaac Newton was born in Woolsthorpe, Lincolnshire, on 25 December 1642. He may be considered one of the truly great investigators of nature. His mother belonged to moderately noble classes and his father, who died before his birth, was a small landowner. His rigid puritan education, the enforced detachment from his mother who remarried to a protestant bishop and the successive rebuilding of a close affectionate relationship with her, encouraged some biographers to suggest Freudian interpretations concerning his neurotic stress, misogyny and temper whims. He was destined to become a country squire, and undertook his first studies at the Grammar School of Grantham. His notable skills for mechanical invention and his inclination for humanistic studies in Hebrew and theology inspired his teachers to recommend him to Cambridge University. He was admitted to Trinity College in June 1661 but, due to the avarice of his mother, was forced to accept the title of subsizar, a term used in the University to mean a poor student who earned his keep by performing menial tasks for his fellow students. In this position, as had occurred previously at Grammar School, Newton was isolated from his fellow students who, when he subsequently became famous did not remember meeting him. He did not distinguish himself in his official studies, and in addition he did not follow an orthodox curriculum. Both in mathematics and in natural philosophy (that is to say in physics) he was a self-taught man, since at that time in Cambridge both disciplines were taught very little. The mechanical world of Descartes and 17
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Figure 5. This is the Newton’s representation of the prism’s experiment. A sun beam OF after passing through the small circular hole F is refracted by a prism A B C and is displayed in the spectrum PYTZ on the front wall. (From Add. Ms. 4002, p 3, Cambridge University Library.)...
The History of the Laser and refraction which he had developed in the previous five years. These Lectiones opticae, written in Latin, were the first physical treatise and the most comprehensive account of his theory of colour. They were used as a basis for the first book of his Opticks, written 20 years later. By contrasting the Lectiones with the Opticks we may see the evolution of Newton’s thought. In his Lectiones, Newton tried to create a mathematical science of colours, whilst as he himself declared, Opticks is an experimental textbook: ‘My design in this Book is not to explain the properties of light by hypotheses but to propose and prove them by reason and experiment’....
Wave and corpuscular theories of light under his name, which travels in a highly eccentric ellipse with a period of about 72 years. This comet last appeared in 1985. In the first book of Principia, the laws of motion, curvilinear and elliptic motions, the laws of collisions, the derivation of central forces and the motion of pendula are all contained. The second book is dedicated to the motion of solid bodies in resisting media, and implies a detailed and systematic confutation of the Cartesian physics of plenum, which alters the real behaviour of bodies moving inside fluids and makes indemonstrable on physical grounds the laws of Kepler. These first two books have a rational axiomatic and deductive structure; the third book starts from these premises and develops inductively the construction of the universe. The author reformulates in a simple and elegant way the Copernican heliocentric theory, adding the most recent contemporary astronomical data; after the demonstration of the laws of Kepler derived from the dynamic principles he had formulated, Newton develops the theory of the Moon’s motion, of tides, the calculations relative to the trajectories of comets and the three body problem. The first edition of Principia (about one thousand copies) had a large European diffusion, even if very few understood its content....
Maxwell’s theory of electromagnetism One hundred years later, in 1864, J C Maxwell (1831–1879) discovered the electromagnetic and inelastic nature of light vibrations, summarizing it in 25
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Wave and corpuscular theories of light Royal, describes Maxwell’s lessons as follows:
‘In those days a professor was little better than a schoolmaster—and Maxwell was not a good schoolmaster; only some four or five of us, in a class of seventy or eighty, got much out of him. We used to remain with him for a couple of hours after lectures, till his terrible wife came and dragged him away to a miserable dinner at three o’clock in the afternoon. By himself he was the most delightful and sympathetic of beings—often dreaming and suddenly awakening—then he spoke of what he had been thinking. Much of it we could not understand at the time, and some of it we afterwards remembered and understood’....
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