Phys 115 1st Edition Lecture 21Outline of Last Lecture I. PolarizationII. Thin Film InterferenceOutline of Current Lecture III. Single Slit InterferenceCurrent Lecture- Light is a wave made up of oscillating electric and magnetic fields.- Polarized light is made up of EM waves whose electric fields are oriented in the same direction.- Unpolarized light is made up of EM waves whose electric fields are randomly oriented with respect to one another.- When light passes through a polarizing sheet, electric field components parallel to sheet’s polarizing direction pass through, while electric field components perpendicular to the polarizing direction do not pass through. - If unpolarized light has an intensity I0, then its intensity after passing through a polarizingsheet will be- If polarized light has an intensity I0, then its intensity after passing through a polarizing sheet will be- whereθ is the angle between the initial electric field direction and the polarizing direction.- Thin Film Interference: Imagine a ray of light is incident on a material made of several thin film layers.- Imagine the angle of incidence is 0o. The rays are drawn with non-zero incident angles inorder to make the diagram easier to interpret.- A light wave undergoes a 180o phase shift if it reflects off of a boundary at which the index of refraction increases.- Wave 2 travels an extra distance 2dx compared to wave 1These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- When wave 2 emerges from the nx = 1.5 layer, it may constructively or destructively interfere with wave 1.- The distance the light wave travels in the nx layer equals 2λx, so when the wave goes back into the n = 1.0 layer, it behaves as if it has been shifted by
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