Introduction To Optics Week 1 Lecture PDF

INTRODUCTION TO OPTICS  LEARNING OUTCOME At the end of the class student is expected to: 1. Gain a basic appreciation of the history of optics and the development of the principal concepts. 2. Have an appreciation for some of the real-world applications of optics. ...

INTRODUCTION TO OPTICS  LEARNING OUTCOME At the end of the class student is expected to: 1. Gain a basic appreciation of the history of optics and the development of the principal concepts. 2. Have an appreciation for some of the real-world applications of optics.  WHAT IS OPTICS Optics is broadly referred to as the study of the behavior of light and its interaction with matter. The study of optics can be categorized into 3 broad subareas: Geometrical Optics Physical Optics Quantum optics O p tics  HISTORY OF OPTICS Application of the optical principles can be traced back to ancient times: 1. Optics of the ancient times 2. Optics in the middle ages 3. Modern Optics  OPTICS IN ANICENT TIMES Ancient Greeks (500-300 BCE) Earliest surviving textbook about optics: “Euclid’s optics” by Euclid (300 BC) Law of reflection: “Catoptrics” by Euclid (300 BC) Refraction in water mentioned by Plato in “The Republic” But they thought that the eye emits rays that reflect off objects (extramission theory of vision)  OPTICS IN THE MIDDLE AGE In the course of his work, Alhazen conducted Ibn Sahl (940-1000BC)Explains the focusing many experiments on the rectilinear (straight of light by curved mirrors and lenses. In his line) propagation of light, reflection and treatise On Burning Mirrors and Lenses. refraction  MODERN OPTICS The Enlightenment or Age of Reason in the 17th and 18th centuries saw the rise of many great thinkers in contributing to our understanding of the world. Most notable of these for their work on the fundamentals of mathematics. Physics and general science was Galileo, Descartes and, of course, Newton.  17TH CENTURY OPTICS Hans Lippershey applied for a patent on the telescope in 1608. Galileo (1564-1642) used a form of telescope to look at our moon, Jupiter and its moons, and the sun. Two of Galileo’s telescopes Galileo’s drawings of the moon  JONNAS KEPLER 1. Discovered total internal reflection use in telescope. 2. Showed how telescopes work. 3. Developed a first-order theory of geometrical optics Johannes Kepler (1571–1630)  WILLIBRORD SNELL Willibrord Snell discovered the Law of Refraction, now named after him. n1 sin(1 ) = n2 sin(2 ) Willibrord Snell (1591-1626) ni is the refractive index of each medium.  RENE DESCARTES In his works on optics, Rene Descartes (1596 - 1650) independently. Derived Snell’s Law, named after Willebrord Snell (1580 - 1626) Rene Descartes (1596-1659)  ISAAC NEWTON Despite Descartes’ adoption of the wave interpretation of light, Isaac Newton (1642 - 1727) came to reject the idea, favoring a particle description of light. This view is known as the corpuscular theory of light. Newton’s own contributions to the field of optics were of great significance Isaac Newton (1642-1727)  CHRISTAIN HUYGENS 1. Huygens extended the wave theory of optics. Christiaan Huygens (1629-1695) 2. He realized that light slowed down on entering dense media. 3. He explained polarization. Huygens‘ principle says that a wave propagates as if the wave-front were composed of an array of point sources each emitting a spherical wave. 18TH AND 19TH CENTURY OPTICS Thomas Young (1773-1829) explained interference and colored fringes and showed that light was a transverse wave. Thomas Young Augustin Fresnel (1788-1827) did experiments to establish the wave theory and derived expressions for reflected and transmitted waves Augustine-Jean Fresenel  MAXWELL JAMES CLERK The great physicist James Clerk Maxwell (1831 - 1879) derived the Maxwell equation. James Clerk Maxwell (1831-1879) This meant that the speed of EM waves c must also be a fundamental constant. He argued that light is a form of electromagnetic radiation.  LIGHT IS AN ELECTROMAGNETIC WAVE The electric (E) and magnetic (B) fields are in phase. The electric field, the magnetic field, and the propagation direction are all perpendicular.  MICHAELSON AND MORLEY Michaelson and Morley attempted to measure the relative motion of the Earth against the luminous ether by interferometer. They found it to be zero, effectively disproving the existence of the luminous ether. Albert Edward Michelson Morley (1852-1931) (1838-1923)  QUTANTUM OPTICS: MAX PLANCK Planck explained that light must be emitted in discrete quanta. Each quanta must contain a certain energy. His views was not well received by the scientific community. Max Planck (1858 - 1947)  QUANTUM OPTICS Einstein took planck’s idea seriously and went further to explain and prove the following: 1. That electromagnetic field itself was quantised. Albert Einstein (1879-1955) 2. He showed that the energy of the electrons emitted by the light is dependent on the frequency. 3. Light is both a wave and a particle.  APPLICATIONS OF OPTICS The applications of optical theory are many and varied. Here we list just a taster of possible applications. 1. Lenses and mirrors 2. Spectroscopy 3. Photonics 4. Fiber optics 5. Computer graphics  LENS & MIRROR In the ancient times the principle of optics were applied in inventing lens and mirrors. Some of the fields and instruments that uses lenses and mirrors: - Optometry and Ophthalmology - Astronomy: Telescope & Microscopes - Photography - Microscopy etc  SPECTROSCOPY It concerns spectral analysis of light. Spectrometer is the instrument used to separate and measure spectral component of physical light. It can be use for; 1. Chemical analysis 2. Astronomy Spectrometer  PHOTONICS Photonic is the science and technology of generating, controlling and detecting photons. Laser is a photonic application. They are used in many ways such as - Reading CD and DVD drivers - Effective for scanning technologies  FIBER OPTICS Fiber optics exploits many region of electromagnetic spectrum. Applied in: - Telecommunication - Internet connectivity -  FURTHER READING Grant R. Fowles, Introduction to Modern Optics, Dover Publications(1989) Eugene Hecht, Optics, Addison-Wesley (2001) Max Born and Emil Wolf, Principles of Optics: Electromagnetic Theory of Propagation, Interference and Diffraction of Light, Cambridge University Press (1999)