Engineering Optics and Optical Techniques工程光学和光学技术.docVIP

Engineering Optics and Optical Techniques LN#1. Electromagnetic Basics and Maxwell’s Equations (Sections 3-1, 3-2, Appendix 1) Propagation of Waves (Chapter 2, Sections 3-3, 3-4) Experimental evidence shows that light propagates as a form of waves consisting transverse, time-varying electric and magnetic fields. The two amplitude-varying transverse vectors, electric field strength E and magnetic field strength H, oscillate at the right angles to each other in phase and to the direction of propagation. They can be expressed in the form of four fundamental equations known as Maxwell’s Equations. “It is true that nature begins by reasoning and ends by experience. Nevertheless, we must begin with experiments and try through it to discover the reason.” - Leonardo da Vinci – Homework #1-1 Read of Chapter 1 for “Brief History” of Optical Science (Clerk) Maxwell’s Equations (1865) – Light is most certainly electromagnetic nature (Classical electrodynamics) For vacuum, air, water or glass (no space charge or ion density, ~ zero electric conductivity): Key: Interdependence of E and B Or their combined and reduced forms, Where E: Electric field [Force/Charge, N/C] B: Magnetic induction [Force/Charge/Velocity, Ns/Cm] Fluid Dynamics vs. Electromagnetics Continuity Analogy: vs. V: flow velocity j: electric current flux Extended Analogy Fluid Dynamics Electromagnetics Field g-Field: Fg = mg E-Field: FE = qE M-Field: FM = qV(B Continuity Flow current flux V = volume flow/area/time = Electric current flux j = electric charge flow/area/time = Volume flow rate q: Electric charge flow rate i: : Ampere = C/s Volume continuity: , (: fluid density Electric charge continuity: , (E: charge density Steady state Incompressible flow Zero or constant space charge condition Arc Angle vs. Solid Angle Arc angle: defined as Total arc length: Solid angle: defined as (normally outward vector definition) Total surface area