OPTOMETRY INTRODUCTION Er. FARUK BIN POYEN Dept. of AEIE, UIT, BU, BURDWAN, WB, INDIA

Contents: 1.Optics 2.Radiometry 3.Photometry 4.Theories about Light 5.Terms related to Radiometry 6.Terms related to Photometry 7.Laws of Illumination 8.Principle of Superposition 9.Wave Property of Particles 10.Wave Particle Duality 9/9/2016OPTOMETRY - INTRODUCTION Er. FARUK BIN POYEN2

OPTICS Branch of Physics where nature and property of light are studied. The scientific study of sight and the behaviour of light, or the properties of transmission and deflection of other forms of radiation. Classified into 9/9/2016OPTOMETRY - INTRODUCTION Er. FARUK BIN POYEN3 Geometrical Optics Rectilinear Propagation of Light Physical Optics Wave Nature of Light Quantum Optics Particle Nature of Light

Radiometry & Photometry Radiometry: Measurement of electromagnetic radiation, including visible light. Radiometric techniques in optics characterize the distribution of the radiation's power in space. Photometry: Measurement of light, in terms of its perceived brightness to the human eye. Photopic Vision: Response of eyes under normal light conditions (555 nm). Scotopic Vision: Response of eyes under low light conditions (507 nm). 9/9/2016OPTOMETRY - INTRODUCTION Er. FARUK BIN POYEN4

Different Theories about Light Corpuscular Theory of Light Newton proposed this theory that treats light as being composed of tiny particles having no mass and high speed. Failed to explain refraction. Wave Theory of Light Huygens proposed light as waves that spread out from the source that generates the light. Each colour is a different wavelength. Supernumerary bows are explained by assuming that light is a wave. Failed to explain propagation in vacuum and existence of aether medium. The Electromagnetic Theory of Light Maxwell proposed light as electromagnetic waves. Propagation in vacuum explained. Quantum (Photon) Theory of Light Light is energy particle named photon. The energy of the photon determines the colour. Dual Theory of Light Light behaves both as a particle and as a wave. 9/9/2016OPTOMETRY - INTRODUCTION Er. FARUK BIN POYEN5

Terms related to Radiometry Radiant Energy Radiant Flux Radiant Intensity Radiance Radiant Sterance Emittance Radiant Excitance Irradiance Radiant Incidence 9/9/2016OPTOMETRY - INTRODUCTION Er. FARUK BIN POYEN6

Terms related to Photometry Point Source Solid Angle Lumen Luminous Intensity Illumination Luminance Luminous Excitance Luminous Sterance 9/9/2016OPTOMETRY - INTRODUCTION Er. FARUK BIN POYEN7

Laws of Illumination 9/9/2016OPTOMETRY - INTRODUCTION Er. FARUK BIN POYEN8

Principle of Superposition For all linear systems, the net response at a given place and time caused by two or more stimuli is the sum of the responses which would have been caused by each stimulus individually. The resultant displacement of two simultaneous waves (blue and green) is the algebraic sum of the two displacements. 9/9/2016OPTOMETRY - INTRODUCTION Er. FARUK BIN POYEN9 Constructive Interference Destructive Interference The superposition of two coherent light waves results in light and dark fringes on a screen.

Wave Property of Particles 9/9/2016OPTOMETRY - INTRODUCTION Er. FARUK BIN POYEN10

Wave Particle Duality 9/9/2016OPTOMETRY - INTRODUCTION Er. FARUK BIN POYEN11

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