Patterned Border Template 1 Purdue University School of Mechanical Engineering ME 587 Engineering Optics Lecture 16: Interference Prof. Robert P. Lucht Room 86, Mechanical Engineering Building School of Mechanical Engineering Purdue University West Lafayette, Indiana (Phone) October 25, 2005

Patterned Border Template 2 Purdue University School of Mechanical Engineering Optical Interference This Lecture Two-Beam Interference Young’s Double Slit Experiment Virtual Sources Newton’s Rings Film Thickness Measurement by Interference Last Lecture Conduction Current in Metals EM Wave Propagation in Metals Skin Depth Plasma Frequency

Patterned Border Template 3 Purdue University School of Mechanical Engineering Two-Beam Interference

Patterned Border Template 4 Purdue University School of Mechanical Engineering Two-Beam Interference Hecht, Optics, Chapter 9.

Patterned Border Template 5 Purdue University School of Mechanical Engineering Two-Beam Interference

Patterned Border Template 6 Purdue University School of Mechanical Engineering Two-Beam Interference

Patterned Border Template 7 Purdue University School of Mechanical Engineering Two-Beam Interference

Patterned Border Template 8 Purdue University School of Mechanical Engineering Conditions for Interference Interference Between Light From Two Sources Sources must be in phase with each other – sources must be coherent Sources must have the same frequency Radiation must overlap within the coherence lengths of each source to produce an interference pattern – discharge lamps have coherence lengths on the order of a few mm, some lasers have coherence lengths on the order of a few km Clearest patterns will be produced when the sources have nearly the same amplitude – maximum contrast

Patterned Border Template 9 Purdue University School of Mechanical Engineering Conditions for Interference Hecht, Optics, Chapter 9.

Patterned Border Template 10 Purdue University School of Mechanical Engineering Young’s Double Slit Interference Expt Hecht, Optics, Chapter 9.

Patterned Border Template 11 Purdue University School of Mechanical Engineering Young’s Double Slit Interference Expt

Patterned Border Template 12 Purdue University School of Mechanical Engineering Young’s Double Slit Interference Expt

Patterned Border Template 13 Purdue University School of Mechanical Engineering Interference Fringes From 2 Point Sources

Patterned Border Template 14 Purdue University School of Mechanical Engineering Interference Fringes From 2 Point Sources Hecht, Optics, Chapter 9.

Patterned Border Template 15 Purdue University School of Mechanical Engineering Interference With Virtual Sources: Fresnel’s Double Mirror Hecht, Optics, Chapter 9.

Patterned Border Template 16 Purdue University School of Mechanical Engineering Interference With Virtual Sources: Fresnel’s Biprism Hecht, Optics, Chapter 9.

Patterned Border Template 17 Purdue University School of Mechanical Engineering Interference With Virtual Sources: Lloyd’s Mirror Hecht, Optics, Chapter 9.

Patterned Border Template 18 Purdue University School of Mechanical Engineering Interference in Dielectric Films

Patterned Border Template 19 Purdue University School of Mechanical Engineering Analysis of Interference in Dielectric Films

Patterned Border Template 20 Purdue University School of Mechanical Engineering Analysis of Interference in Dielectric Films

Patterned Border Template 21 Purdue University School of Mechanical Engineering Analysis of Interference in Dielectric Films

Patterned Border Template 22 Purdue University School of Mechanical Engineering Fringes of Equal Inclination

Patterned Border Template 23 Purdue University School of Mechanical Engineering Fringes of Equal Thickness

Patterned Border Template 24 Purdue University School of Mechanical Engineering Fringes of Equal Thickness: Newton’s Rings

Patterned Border Template 25 Purdue University School of Mechanical Engineering Fringes of Equal Thickness: Newton’s Rings