Announcements 1/20/12 Prayer

Review Question (not graded) In an electro-magnetic wave, the electric and magnetic fields: are always in phase always have a relative phase shift can have a relative phase shift when absorption takes place

Reading Quiz The most important frequency for the optical properties of a conductor is the: decay frequency, wD plasma frequency, wP reflection frequency, wR resonance frequency, w0

Reading Quiz In a conductor, the optical properties are described by a ___________ index of refraction: totally real totally imaginary partially real and partially imaginary

Metals: complex n From P&W Fig 2.6 (and HW P2.8…)

Reflectance vs. Wavelength From Hecht Plasma frequency

Reading Quiz The vector that gives the direction of energy transfer through space in an E-M wave is called the: Clausius vector flow vector Michelson vector polarization vector Poynting vector

Energy stored in fields (appendix)

Derivation of Poynting Theorem Bottom eqn minus top eqn… Multiply both sides by -1/m0 …

Derivation of Poynting Theorem, cont. like a flux, call it S energy density, ufield (J includes both Jfree and Jpolar) has units of energy density/time… call it “dumedium/dt” compare to Eqn of Cont.

Intensity