Chapter 8: Physical Optics
|
|
- Donald Lambert
- 5 years ago
- Views:
Transcription
1 Chapter 8: Physical Optics Whether light is a particle or a wave had puzzled physicists for centuries. In this chapter, we only analyze light as a wave using basic optical concepts such as interference and diffraction
2 Overview Physical Optics Huygens Principle Interference Diffraction Double-slits Interference Thin Film Single-slit Diffraction Diffraction Grating Air Wedge & Newton s Ring
3 8.1 Huygens Principle State Huygens principle Sketch and explain the wavefront of light after passing through a single slit and obstacle using Huygens principle Learning Objectives
4 Wavefront Wavefront is defined as a line or surface, in the path of a wave motion, on which the disturbances at every point have the same phase. Wavefront A B C D E F Direction of movement, v A B C D E F Direction of movement, v Wave λ Line joining all point of adjacent wave, e.g. A, B and C or D,E and F are in phase Wavefront Wave front always perpendicular to the direction of wave propagation.
5 Types of Wavefront
6 Ray and Beam of Light Ray is defined as a line represents the direction of travel of a wave. Ray Wavefront λ Beam of light is a collection of rays or a column of light. Source of light from infinity
7 Huygens Principle Huygens principle states that every point on a wavefront can be considered as a source of secondary wavelets that spread out in the forward direction at the speed of the wave. The new wavefront is the envelope of all the secondary wavelets - i.e. the tangent to all of them. When applying Huygens s principle, show the centres of the wavelets the wavelets from these centres the line touching these wavelets draw an arrow to show the direction of the ray (normal to wavefront)
8 Huygens Principle At t = 0 s Ray At t = Δt s 1. Draw a wavefront of a plane wave as a straight line. 2. Choose a few points (5 points) on the wavefront as sources of wavelets. Since there is no backward-moving wave, the wavelets are hemispheres. 3. Draw 5 semicircles of equal radius, one centered on each of the five points. 4. Draw a line tangent to the five semicircles: this represents the wavefront at the later time.
9 Huygens's Principle Plane wavefront Spherical wavefront
10 Huygens's Principle Diffraction of wave at a single slit Diffraction of wave at an obstacle
11 Example 1 The figure shows a point light source P on the ground. Draw the wavefront from point P at time t = 1 s and t = 2 s.
12 Example 1 Solution Ray P t = 1 s t = 2 s
13 8.2 Constructive Interference and Destructive Interference Define coherence State the condition for interference of light State the conditions of constructive and destructive interference Learning Objectives
14 Coherence A stable interference pattern can be produced if the sources of wave are coherent. The two sources of wave are coherent if they have: the same phase difference (constant) the same wavelength (monochromatic)
15 Interference Interference of light is defined as the situation when two or more light waves meet (superposed) at a point, a bright or a dark region will be produced in accordance to the Principle of Superposition. Principle of superposition states the resultant displacement at any point is the vector sum of the displacements due to the two light waves. Conditions for fixed interference two coherent sources same or approximately same amplitude distance between the coherent sources, d λ
16 Constructive Interference Constructive interference is defined as a reinforcement of amplitudes of light waves that will produce a bright fringe (maximum). a a 2a a 2a a Two coherent sources are in phase
17 Destructive Interference Destructive interference is defined as a total cancellation of amplitudes of light waves that will produce a dark fringe (minimum). a a Two coherent sources are in anti-phase
18 Path Difference Path difference is the difference between two paths of waves from two different sources at a point (a difference in path length). Path Difference, L = S 2 P - S 1 P = x 2 x 1
19 Two Coherent Sources In Phase In phase sources Constructive interference
20 Two Coherent Sources In Phase Bright fringe (Constructive) 3.0λ Dark fringe (Destructive) 3.5λ L 0,, 2, 3,... m where m 3.0λ 0, 1, 2, 3, λ 3 5 L,,, m 2 where m 0, 1, 2, 3,...
21 Two Coherent Sources Anti Phase Anti phase sources Destructive interference
22 Two Coherent Sources Anti Phase Bright fringe (Constructive) 3.5λ Dark fringe (Destructive) 3.0λ 4.0λ 3.0λ 3 5 L,,, m 2 where m 0, 1, 2, 3,... L 0,, 2, 3,... m where m 0, 1, 2, 3,...
23 Example 2 Two point sources X and Y emit waves of wavelength 2.0 cm in phase. The point P is 6.0 cm from X and 10.0 cm from Y. Another point Q is 7.0 cm from X and 4.0 cm from Y. What is the path difference of waves from X and Y at a. The point P and b. The point Q? Hence deduce whether constructive interference or destructive interference occurs at P and Q.
24 Example 2 Solution
25 8.3 Interference of Transmitted Light Through Double-slits Derive and use: md y i. m for bright fringes (maxima) y m d 1 m D 2 d ii. for dark fringes (minima) where m = 0, ±1, ±2, ±3, Use y D d and explain the effect of changing any of the variables Learning Objectives
26 Light source S 0 Young s Double Slits Experiment S 1 S 2 The coherent waves in phase from the two slits. Screen Intensity Max Min Max Min Max Min Max Min Max Interference pattern on the screen. 1 st order dark 1 st dark Order m = 2 m = 2 m = 1 m = 1 m = 0 m = 0 m = 0 m = 1 m = 1 m = 2 m = 2 Fringe 3 rd dark 2 nd bright 2 nd dark 1 st bright 1 st dark Central bright 1 st dark 1 st bright 2 nd dark 2 nd bright 3 rd dark
27 Young s Double Slits Experiment i. Wavefront from light source falls on a narrow slit S 0 and diffraction occurs. ii. Every point on the wavefront that falls on S 0 acts as sources of secondary wavelets that will produce a new wavefront that propagate to slits S 1 and S 2. iii. S 1 and S 2 are produced two new sources of coherent waves in phase because they originate from the same wavefront and their distance from S are equal. iv. Constructive interference and destructive interference occur at different points on the screen to produce a pattern of alternating bright and dark fringes.
28 Derivation of Young s Double-slit Equations P S 1 y m d A θ θ C S 2 ΔL D
29 Derivation of Young s Double-slit Equations y m d θ θ D ΔL tan y m D sin L d since θ is very small, tan θ sin θ, hence y m D L d
30 Derivation of Young s Double-slit Equations To obtain constructive interference, L m Therefore, the separation between central bright and m th bright fringes, y m is given by y m md d m : order 0, 1, 2,...
31 Derivation of Young s Double-slit Equations To obtain destructive interference, L m 1 2 Therefore, the separation between central bright and m th bright fringes, y m is given by y m 1 m D 2 d m : order 0, 1, 2,...
32 Separation Between Two Consecutive Fringes, Δy Separation between two consecutive (successive) dark or bright fringes: y y y m1 y m m 1 D d D d md d
33 Appearance of Fringes on Young s Double-Slit Experiment From equation y D d Δy, fringes are wider Δy, fringes are narrower y depends on : i) the wavelength of light, λ y ii) the distance apart, d of the double slits y 1 d iii) distance between slits and the screen, D y D
34 Appearance of Fringes on Young s Double-Slit Experiment If white light is used the central bright fringe is white, and the fringes on either side are coloured. Blue is the colour nearer to the central fringe and red is farther away as shown in figure below. red red blue blue
35 What would happen to the interference pattern if the entire experiment were submerged in water? Submerging the double-slit experiment in water would reduce the wavelength of the light from to /n, where n = 1.33 is the refraction index of water. Therefore, the bright or dark fringe separation would be reduced, the interference pattern fringes get closer to each other. y
36 Example 3 An interference pattern is formed on a screen when light of wavelength 550 nm is incident on two parallel slits 50 μm apart. The second-order bright fringe is 4.5 cm from the center of the central maximum. How far from the slits is the screen?
37 Example 3 Solution
38 Example 4 In a Young s double experiment, the slits separation is 1.0 mm. The distance between the slits and the screen is 1.0 m. The wavelength of the sodium light used is cm. a. Calculate the separation between two consecutive dark fringes. b. If the sodium light is replaced with a blue light, what are the changes to the interference pattern on the screen?
39 Example 4 Solution
40 Example 4 Solution
41 Example 5 A double-slits pattern is view on a screen 1.00 m from the slits. If the third order minima are 25.0 cm apart, determine the distance between the first order minimum and fourth order maximum on the screen. *Hint: determine the ratio of wavelength and separation between the slits first 3 rd order minimum d S 1 S 2 D y 3 y 3 zeroth order maximum y 3 3 rd order minimum
42 Example 5 Solution
43 Example 5 Solution
44 Example 5 Solution
45 Example 6 A monochromatic light of wavelength 600 nm falls on a system of double-slits of unknown slit separation. At the same time, the double-slits is illuminated by a monochromatic light of unknown wavelength. It was observed that the 4 th order maximum of the known wavelength light overlapped with the 5 th order maximum of the unknown wavelength light. Find the wavelength of the unknown wavelength light.
46 Example 6 Solution
47 Example 6 Solution
48 Example 7 Suppose you pass the light from a He-Ne laser through two slits separated by mm and find that the third bright line is formed at an angle of o relative to the incident beam. What is the wavelength of the light?
49 Example 7 Solution
50 8.4 Interference of Reflected Light in Thin Films Identify the occurrence of phase change upon reflection Explain with the aid of a diagram the interference of light in thin films at normal incidence Use the following equation: For reflected light with no phase difference: Constructive interference (or reflective coating) 2nt m Destructive interference (or anti-reflective coating) 1 2nt m 2 Learning Objectives
51 8.4 Interference of Reflected Light in Thin Films For reflected light with phase difference π rad: Constructive interference Destructive interference 1 2nt m 2 2nt m where m = 0, ±1, ±2, ±3, Learning Objectives
52 Occurrence of Phase Change Upon Reflection Less dense Denser Phase change = π rad Reflected Transmitted Reflected Transmitted Denser Less dense Phase change = 0 rad
53 Non-reflective Coating Phase difference between ray 1 and ray 2, 0 2 sources in phase Based on the diagram, ray 2 travels an extra distance of 2t before the waves combine. L 2t
54 Non-reflective Coating Since ray 1 and ray 2 are in phase, constructive interference occurs when the (path length in thin film) extra distance travelled by ray 2 is equal to a whole number of wavelength L m n and n n where λ n is the wavelength of light in medium (thin film) λ is the wavelength of light in vacuum For constructive interference: m 2t 2nt m n m 0, 1, 2,...
55 Non-reflective Coating In such case, destructive interference occurs when the (path length in thin film) extra distance traveled by ray 2 is equal to an odd number of half-wavelength, so that the ray 2 would be in phase with the ray 1: L m 1 2 n and n n For destructive interference: 1 1 2t m 2nt m 2 n 2 m 0, 1, 2,...
56 Reflective Coating Phase difference between ray 1 and ray 2, 0 2 sources anti phase Based on the diagram, ray 2 travels an extra distance of 2t before the waves combine. L 2t
57 Reflective Coating Since ray 1 and ray 2 are anti phase, constructive interference occurs when the (path length in thin film) extra distance travelled by ray 2 is equal to an odd number of half-wavelength L m 1 2 n and n n For constructive interference: 1 1 2t m 2nt m 2 n 2 m 0, 1, 2,...
58 Reflective Coating In such case, destructive interference occurs when the (path length in thin film) extra distance traveled by ray 2 is equal to a whole number of wavelength, so that the ray 2 would be in phase with the ray 1: L mn and n n For destructive interference: m 2t 2nt m n m 0, 1, 2,... Example: soap bubble
59 Example 8 Light is at normal incidence on a thin soap film of refractive index 1.30 and thickness 0.15 µm. Determine the maximum wavelength of the reflected light that undergoes a. constructive interference b. destructive interference
60 Example 8 Solution
61 Example 8 Solution
62 Example 9 White light is incident normally on a lens (n 2 = 1.52) that is coated with a film of MgF 2 (n = 1.38). For what minimum thickness of the film will yellow light (λ vacuum = 550 nm) be missing in the reflected light?
63 Example 9 Solution
64 Example 10 A lens appears greenish yellow (λ vacuum = 570 nm is strongest) when white light reflects from it. What minimum thickness of coating (n = 1.25) do you think is used on such a (glass) lens?
65 Example 10 Solution
66 8.5 Interference of Reflected Light in Air Wedge and Newton s Rings Explain with the aid of a diagram the interference in air wedge Use for air wedge: i. t m for bright fringes (maxima) ii. 2t m for dark fringes (minima) where m = 0, 1, 2, 3, Use diagram to explain qualitatively the formation of Newton s rings and the centre dark spot Learning Objectives
67 Air Wedge no phase change S L Q π rad phase change Phase difference between ray LO and ray BQ, 0 X α l O B L P t air T Y 2 sources anti phase Based on the diagram, ray BQ travels an extra distance of 2t before the waves combine. 1 st dark fringe m = x The two rays (ray LO & BQ) are coherent since both have originated from the same source and produces a produces interference pattern.
68 Air Wedge Since ray LO and ray BQ are anti phase, constructive interference occurs when the (path length in thin film) extra distance travelled by ray 2 is equal to an odd number of half-wavelength 1 L m 2 where λ is the wavelength of light in vacuum For constructive interference: 1 2t m m 0, 1, 2,... 2
69 Air Wedge In such case, destructive interference occurs when the (path length in thin film) extra distance traveled by ray BQ is equal to a whole number of wavelength, so that the ray 2 would be in phase with the ray LO: L m For destructive interference: 2 t m m 0, 1, 2,...
70 Air Wedge Based on the diagram: T tan L t l tan t l Therefore, the separation between first dark and m th bright fringes, is given by 2 l m 1 2 tan Therefore, the separation between first dark and m th dark fringes, is given by l m 2 tan Equation for separation between consecutive dark fringes or bright fringes : x 2 tan
71 Newton s Rings Phase difference between ray LO and ray BQ, 0 2 sources anti phase S L Q Based on the diagram, ray BQ travels an extra distance of 2t before the waves combine. t X d O P B The two rays (ray LO & BQ) are coherent since both have originated from the same source and produces a produces interference pattern.
72 Newton s Rings The interference pattern is a series of circular interference fringes because of a curved piece of glass with a spherical cross section (plano-convex lens). Path difference = ½λ Bright ring Path difference = λ Dark ring At X, t = 0 and thus the path difference = 0. A dark spot is observed at X due to the phase change of π radian for ray BQ. (ray LO & BQ are anti phase) From Figure, the rings become more closely spaced as one moves farther from the centre of the Newton s ring because the thickness of air film increases rapidly.
73 Example 11 An air wedge is formed by placing a human hair between two glass slides of length 44 mm on one end, and allowing them to touch on the other end. When this wedge is illuminated by a red light of wavelength 771 nm, it is observed to have 265 bright fringes. Determine a. the diameter of hair b. the angle of air wedge c. the thickness of the air film for 99 th dark fringe to be observed d. the separation between two consecutive bright fringes
74 Example 11 Solution
75 Example 11 Solution
76 Example 11- Solution
77 Example 11 Solution
78 Example 12 A plate of glass 10.0 cm long is placed in contact with a second plate and held at small angle with it by a metal strip mm thick placed under one end. The space between the plates is filled with air. The glass is illuminated from above with light having a wavelength of 635 nm. How many interference fringes are observed per centimeter in the reflected light?
79 Example 12 Solution
80 8.6 Diffraction by a Single Slit Define diffraction Explain with the aid of a diagram the diffraction of a single slit. Use: nd i. for dark fringes (minima) y n a 1 2 a n D ii. y n for bright fringes (maxima) where n = 0, ±1, ±2, ±3, Learning Objectives
81 Diffraction Diffraction of light is defined as the bending of waves as they travel around obstacles or pass through an aperture comparable to the wavelength of the waves.
82 Diffraction by a Single Slit S 1 1 n = 2 2 nd bright n = 2 2 nd dark n = 1 1 st bright n = 1 1 st dark Central bright n = 1 1 st dark n = 1 1 st bright n = 2 2 nd dark n = 2 2 nd bright single slit intensity screen
83 Formation of Diffraction by a Single Slit According to Huygen s principle, wavefront from light source falls on a narrow slit and diffraction occurs. Every point on the wavefront that falls on the slit acts as sources of secondary wavelets and superposed each another to form an interference pattern on the screen.
84 Formation of Diffraction by a Single Slit The key idea is that every point on wave front can be paired with another point that is a 2 away. If the path different is λ 2, the wavelets will arrive at the screen anti phase and interfere destructively. a 2 sin n n 2 a sinn n For bridge fringe, the general equation is: 1 a sinn n 2
85 Formation of Diffraction by a Single Slit Distance of n th order minimum (dark fringe) from central maximum (centre bright): y n nd a Distance of n th order maximum (bright fringe) from central maximum (central bright) y n n 1 2 a D n 1, 2, 3,..
86 Central Maximum (Bright) Fringe The wavelets going straight forward all travel in the same distance to the screen. Thus they arrive in phase and interfere constructively to produce the central maximum of diffraction patter at θ = 0. θ = 0 For first minimum (n = 1), the angle of diffraction is θ 1, but the angle 2θ 1 is the angle subtended by the central maximum. The width of central maximum is 2y 1 (equation for first dark) To calculate the maximum number of orders observed, θ = 90 o
87 Example 13 A monochromatic light of wavelength m passes through a single slit of width m. a. Calculate the width of central maximum: i. in degrees; ii. in centimeters, on a screen 5 cm away from the slit b. Find the number of minimum that can be observed.
88 Example 13 Solution
89 Example 13 Solution
90 Example 14 How many bright fringes will be produced on the screen if a green light of wavelength 553 nm is incident on a slit of width 8.00 µm?
91 Example 14 Solution
92 8.7 Diffraction Grating Explain with the aid of a diagram the formation of diffraction Apply d sin n where d 1 N Learning Objectives
93 Diffraction Grating Diffraction grating is defined as a large number of equally spaced parallel slits. Pattern of diffraction grating:
94 Diffraction Grating Diffraction grating can be made by ruling very fine parallel lines on glass (transmission grating) or metal (reflection grating) by a very precise machine. The untouched spaces between the lines serve as the slits as shown in figure below. a. The spaces between the lines are the slits, for example: if there are four lines then we have 3 slits. b. If there N lines per unit length, then slit separation, d is given by: d 1 N c. The light that passes through the slits are coherent, d. Interference pattern is narrower and sharper than double slits
95 Formation of Diffraction: First order maximum (n = 1) Incoming plane wavefront of light Central or zeroth order maximum (n = 0) diffraction grating L First order maximum (n = 1) d θ θ
96 Formation of Diffraction: According to Huygen s principle, when light is incident on a diffraction grating, each slit will become a secondary source of light so that superposition of light waves from each source will produce diffraction images of regular orders on a screen Based on the diagram: L L d sin d θ θ The condition for constructive interference is the path difference between the slits must be a whole number of wavelength, λ. L n Hence d sin n n 0, 1, 2, 3,..
97 Extra Knowledge A CD surface acts like diffraction grating because it has many finely space grooves on its surface.
98
99 Example 15 A diffraction grating with 600 lines per mm is illuminated normally with a monochromatic light of wavelength 589 nm. Calculate a. the angles of the first-order and second-order maximum lines from the zero-order maximum line. b. the number of orders that can be observed.
100 Example 15 Solution
101 Example 15 Solution
102 Example 15 Solution
103 Example 16 When a blue light of wavelength 465 nm illuminates a diffraction grating, it produces a 1 st order maximum but no 2 nd order maximum. a. Explain the absence of 2 nd order maximum. b. What is the maximum spacing between lines on this grating?
104 Example 16 Solution
105 Example 17 How many bright fringes are produced when a grating with a spacing of m is illuminated normally with light of wavelength m?
106 Example 17 Solution
107
Textbook Reference: Physics (Wilson, Buffa, Lou): Chapter 24
AP Physics-B Physical Optics Introduction: We have seen that the reflection and refraction of light can be understood in terms of both rays and wave fronts of light. Light rays are quite compatible with
More informationInterference of Light
Interference of Light Review: Principle of Superposition When two or more waves interact they interfere. Wave interference is governed by the principle of superposition. The superposition principle says
More informationUNIT 102-9: INTERFERENCE AND DIFFRACTION
Name St.No. - Date(YY/MM/DD) / / Section Group # UNIT 102-9: INTERFERENCE AND DIFFRACTION Patterns created by interference of light in a thin film. OBJECTIVES 1. Understand the creation of double-slit
More informationChapter 25. Wave Optics
Chapter 25 Wave Optics Interference Light waves interfere with each other much like mechanical waves do All interference associated with light waves arises when the electromagnetic fields that constitute
More informationCollege Physics B - PHY2054C
Young College - PHY2054C Wave Optics: 10/29/2014 My Office Hours: Tuesday 10:00 AM - Noon 206 Keen Building Outline Young 1 2 3 Young 4 5 Assume a thin soap film rests on a flat glass surface. Young Young
More informationWhere n = 0, 1, 2, 3, 4
Syllabus: Interference and diffraction introduction interference in thin film by reflection Newton s rings Fraunhofer diffraction due to single slit, double slit and diffraction grating Interference 1.
More informationDr. Quantum. General Physics 2 Light as a Wave 1
Dr. Quantum General Physics 2 Light as a Wave 1 The Nature of Light When studying geometric optics, we used a ray model to describe the behavior of light. A wave model of light is necessary to describe
More informationModels of Light The wave model: The ray model: The photon model:
Models of Light The wave model: under many circumstances, light exhibits the same behavior as sound or water waves. The study of light as a wave is called wave optics. The ray model: The properties of
More informationEM Waves Practice Problems
PSI AP Physics 2 Name 1. Sir Isaac Newton was one of the first physicists to study light. What properties of light did he explain by using the particle model? 2. Who was the first person who was credited
More informationDiffraction. Factors that affect Diffraction
Diffraction What is one common property the four images share? Diffraction: Factors that affect Diffraction TELJR Publications 2017 1 Young s Experiment AIM: Does light have properties of a particle? Or
More informationIntermediate Physics PHYS102
Intermediate Physics PHYS102 Dr Richard H. Cyburt Assistant Professor of Physics My office: 402c in the Science Building My phone: (304) 384-6006 My email: rcyburt@concord.edu My webpage: www.concord.edu/rcyburt
More informationInterference Effects. 6.2 Interference. Coherence. Coherence. Interference. Interference
Effects 6.2 Two-Slit Thin film is a general property of waves. A condition for is that the wave source is coherent. between two waves gives characteristic patterns due to constructive and destructive.
More informationChapter 35 &36 Physical Optics
Chapter 35 &36 Physical Optics Physical Optics Phase Difference & Coherence Thin Film Interference 2-Slit Interference Single Slit Interference Diffraction Patterns Diffraction Grating Diffraction & Resolution
More informationf. (5.3.1) So, the higher frequency means the lower wavelength. Visible part of light spectrum covers the range of wavelengths from
Lecture 5-3 Interference and Diffraction of EM Waves During our previous lectures we have been talking about electromagnetic (EM) waves. As we know, harmonic waves of any type represent periodic process
More informationChapter 24. Wave Optics
Chapter 24 Wave Optics Wave Optics The wave nature of light is needed to explain various phenomena Interference Diffraction Polarization The particle nature of light was the basis for ray (geometric) optics
More informationChapter 24. Wave Optics
Chapter 24 Wave Optics Wave Optics The wave nature of light is needed to explain various phenomena Interference Diffraction Polarization The particle nature of light was the basis for ray (geometric) optics
More informationChapter 24 The Wave Nature of Light
Chapter 24 The Wave Nature of Light 24.1 Waves Versus Particles; Huygens Principle and Diffraction Huygens principle: Every point on a wave front acts as a point source; the wavefront as it develops is
More informationChapter 37. Wave Optics
Chapter 37 Wave Optics Wave Optics Wave optics is a study concerned with phenomena that cannot be adequately explained by geometric (ray) optics. Sometimes called physical optics These phenomena include:
More informationMichelson Interferometer
Michelson Interferometer The Michelson interferometer uses the interference of two reflected waves The third, beamsplitting, mirror is partially reflecting ( half silvered, except it s a thin Aluminum
More informationElectricity & Optics
Physics 24100 Electricity & Optics Lecture 27 Chapter 33 sec. 7-8 Fall 2017 Semester Professor Koltick Clicker Question Bright light of wavelength 585 nm is incident perpendicularly on a soap film (n =
More informationChapter 82 Example and Supplementary Problems
Chapter 82 Example and Supplementary Problems Nature of Polarized Light: 1) A partially polarized beam is composed of 2.5W/m 2 of polarized and 4.0W/m 2 of unpolarized light. Determine the degree of polarization
More informationChapter 24. Wave Optics
Chapter 24 Wave Optics hitt1 An upright object is located a distance from a convex mirror that is less than the mirror's focal length. The image formed by the mirror is (1) virtual, upright, and larger
More informationPhysics 272 Lecture 27 Interference (Ch ) Diffraction (Ch )
Physics 272 Lecture 27 Interference (Ch 35.4-5) Diffraction (Ch 36.1-3) Thin Film Interference 1 2 n 0 =1 (air) t n 1 (thin film) n 2 Get two waves by reflection off of two different interfaces. Ray 2
More informationUnit 5.C Physical Optics Essential Fundamentals of Physical Optics
Unit 5.C Physical Optics Essential Fundamentals of Physical Optics Early Booklet E.C.: + 1 Unit 5.C Hwk. Pts.: / 25 Unit 5.C Lab Pts.: / 20 Late, Incomplete, No Work, No Units Fees? Y / N 1. Light reflects
More informationChapter 37. Interference of Light Waves
Chapter 37 Interference of Light Waves Wave Optics Wave optics is a study concerned with phenomena that cannot be adequately explained by geometric (ray) optics These phenomena include: Interference Diffraction
More informationInterference. Electric fields from two different sources at a single location add together. The same is true for magnetic fields at a single location.
Interference Electric fields from two different sources at a single location add together. The same is true for magnetic fields at a single location. Thus, interacting electromagnetic waves also add together.
More informationCHAPTER 26 INTERFERENCE AND DIFFRACTION
CHAPTER 26 INTERFERENCE AND DIFFRACTION INTERFERENCE CONSTRUCTIVE DESTRUCTIVE YOUNG S EXPERIMENT THIN FILMS NEWTON S RINGS DIFFRACTION SINGLE SLIT MULTIPLE SLITS RESOLVING POWER 1 IN PHASE 180 0 OUT OF
More informationINTERFERENCE. where, m = 0, 1, 2,... (1.2) otherwise, if it is half integral multiple of wavelength, the interference would be destructive.
1.1 INTERFERENCE When two (or more than two) waves of the same frequency travel almost in the same direction and have a phase difference that remains constant with time, the resultant intensity of light
More informationINTERFERENCE. (i) When the film is quite thin as compared to the wavelength of light,
(a) Reflected System: For the thin film in air the ray BG suffers reflection at air medium (rare to denser) boundary, it undergoes a phase change of π and a path change of λ/2, while the ray DF does not,
More informationDEVIL PHYSICS THE BADDEST CLASS ON CAMPUS IB PHYSICS
DEVIL PHYSICS THE BADDEST CLASS ON CAMPUS IB PHYSICS LSN 9-3: INTERFERENCE Intro Video: Interference of Waves Questions From Reading Activity? Essential Idea: Interference patterns from multiple slits
More informationspecular diffuse reflection.
Lesson 8 Light and Optics The Nature of Light Properties of Light: Reflection Refraction Interference Diffraction Polarization Dispersion and Prisms Total Internal Reflection Huygens s Principle The Nature
More informationLecture PowerPoints. Chapter 24 Physics: Principles with Applications, 7 th edition Giancoli
Lecture PowerPoints Chapter 24 Physics: Principles with Applications, 7 th edition Giancoli This work is protected by United States copyright laws and is provided solely for the use of instructors in teaching
More informationSingle slit diffraction
Single slit diffraction Book page 364-367 Review double slit Core Assume paths of the two rays are parallel This is a good assumption if D >>> d PD = R 2 R 1 = dsin θ since sin θ = PD d Constructive interference
More informationUNIT VI OPTICS ALL THE POSSIBLE FORMULAE
58 UNIT VI OPTICS ALL THE POSSIBLE FORMULAE Relation between focal length and radius of curvature of a mirror/lens, f = R/2 Mirror formula: Magnification produced by a mirror: m = - = - Snell s law: 1
More informationDIFFRACTION 4.1 DIFFRACTION Difference between Interference and Diffraction Classification Of Diffraction Phenomena
4.1 DIFFRACTION Suppose a light wave incident on a slit AB of sufficient width b, as shown in Figure 1. According to concept of rectilinear propagation of light the region A B on the screen should be uniformly
More informationInterference of Light
Interference of Light Young s Double-Slit Experiment If light is a wave, interference effects will be seen, where one part of wavefront can interact with another part. One way to study this is to do a
More informationLecture 21. Physics 1202: Lecture 22 Today s Agenda
Physics 1202: Lecture 22 Today s Agenda Announcements: Team problems today Team 16: Navia Hall, Laura Irwin, Eric Kaufman Team 18: Charles Crilly Jr, Kyle Eline, Alexandra Vail Team 19: Erica Allen, Shana
More informationAH Division of Wavefront and Amplitude Answers
AH Division of Wavefront and Amplitude Answers 1. Interference. 2. a) Splitting a single light beam into two beams, a reflected beam and a transmitted beam, at a surface between two media of two different
More informationInterference & Diffraction
Electromagnetism & Light Interference & Diffraction https://youtu.be/iuv6hy6zsd0?t=2m17s Your opinion is very important to us. What study material would you recommend for future classes of Phys140/141?
More informationPHYSICS. Chapter 33 Lecture FOR SCIENTISTS AND ENGINEERS A STRATEGIC APPROACH 4/E RANDALL D. KNIGHT
PHYSICS FOR SCIENTISTS AND ENGINEERS A STRATEGIC APPROACH 4/E Chapter 33 Lecture RANDALL D. KNIGHT Chapter 33 Wave Optics IN THIS CHAPTER, you will learn about and apply the wave model of light. Slide
More informationDiffraction: Propagation of wave based on Huygens s principle.
Diffraction: In addition to interference, waves also exhibit another property diffraction, which is the bending of waves as they pass by some objects or through an aperture. The phenomenon of diffraction
More informationLecture 39. Chapter 37 Diffraction
Lecture 39 Chapter 37 Diffraction Interference Review Combining waves from small number of coherent sources double-slit experiment with slit width much smaller than wavelength of the light Diffraction
More informationChapter 24. Wave Optics. Wave Optics. The wave nature of light is needed to explain various phenomena
Chapter 24 Wave Optics Wave Optics The wave nature of light is needed to explain various phenomena Interference Diffraction Polarization The particle nature of light was the basis for ray (geometric) optics
More informationLecture 16 Diffraction Ch. 36
Lecture 16 Diffraction Ch. 36 Topics Newtons Rings Diffraction and the wave theory Single slit diffraction Intensity of single slit diffraction Double slit diffraction Diffraction grating Dispersion and
More informationAP Physics Problems -- Waves and Light
AP Physics Problems -- Waves and Light 1. 1975-4 (Physical Optics) a. Light of a single wavelength is incident on a single slit of width w. (w is a few wavelengths.) Sketch a graph of the intensity as
More informationChapter 36. Diffraction. Dr. Armen Kocharian
Chapter 36 Diffraction Dr. Armen Kocharian Diffraction Light of wavelength comparable to or larger than the width of a slit spreads out in all forward directions upon passing through the slit This phenomena
More information14 Chapter. Interference and Diffraction
14 Chapter Interference and Diffraction 14.1 Superposition of Waves... 14-14.1.1 Interference Conditions for Light Sources... 14-4 14. Young s Double-Slit Experiment... 14-4 Example 14.1: Double-Slit Experiment...
More informationChapter 15. Light Waves
Chapter 15 Light Waves Chapter 15 is finished, but is not in camera-ready format. All diagrams are missing, but here are some excerpts from the text with omissions indicated by... After 15.1, read 15.2
More informationPhysical or wave optics
Physical or wave optics In the last chapter, we have been studying geometric optics u light moves in straight lines u can summarize everything by indicating direction of light using a ray u light behaves
More informationlight Chapter Type equation here. Important long questions
Type equation here. Light Chapter 9 Important long questions Q.9.1 Describe Young s double slit experiment for the demonstration of interference of. Derive an expression for fringe spacing? Ans. Young
More informationCHAPTER 24 The Wave Nature of Light
CHAPTER 24 The Wave Nature of Light http://www.physicsclassroom.com/class/light/lighttoc.html Units Waves Versus Particles; Huygens Principle and Diffraction Huygens Principle and the Law of Refraction
More informationCollege Physics 150. Chapter 25 Interference and Diffraction
College Physics 50 Chapter 5 Interference and Diffraction Constructive and Destructive Interference The Michelson Interferometer Thin Films Young s Double Slit Experiment Gratings Diffraction Resolution
More informationDiffraction. Introduction: Diffraction is bending of waves around an obstacle (barrier) or spreading of waves passing through a narrow slit.
Introduction: Diffraction is bending of waves around an obstacle (barrier) or spreading of waves passing through a narrow slit. Diffraction amount depends on λ/a proportion If a >> λ diffraction is negligible
More informationLIGHT. Descartes particle theory, however, could not be used to explain diffraction of light.
1 LIGHT Theories of Light In the 17 th century Descartes, a French scientist, formulated two opposing theories to explain the nature of light. These two theories are the particle theory and the wave theory.
More informationChapter 38 Wave Optics (II)
Chapter 38 Wave Optics (II) Initiation: Young s ideas on light were daring and imaginative, but he did not provide rigorous mathematical theory and, more importantly, he is arrogant. Progress: Fresnel,
More informationPHY 222 Lab 11 Interference and Diffraction Patterns Investigating interference and diffraction of light waves
PHY 222 Lab 11 Interference and Diffraction Patterns Investigating interference and diffraction of light waves Print Your Name Print Your Partners' Names Instructions April 17, 2015 Before lab, read the
More informationChapter 36. Diffraction. Copyright 2014 John Wiley & Sons, Inc. All rights reserved.
Chapter 36 Diffraction Copyright 36-1 Single-Slit Diffraction Learning Objectives 36.01 Describe the diffraction of light waves by a narrow opening and an edge, and also describe the resulting interference
More informationPHYSICS - CLUTCH CH 32: WAVE OPTICS.
!! www.clutchprep.com CONCEPT: DIFFRACTION Remember! Light travels in a straight line so long as it isn t disturbed - This allows light to be described as RAYS A common way to disturb light is to have
More informationThe sources must be coherent. This means they emit waves with a constant phase with respect to each other.
CH. 24 Wave Optics The sources must be coherent. This means they emit waves with a constant phase with respect to each other. The waves need to have identical wavelengths. Can t be coherent without this.
More informationPY212 Lecture 25. Prof. Tulika Bose 12/3/09. Interference and Diffraction. Fun Link: Diffraction with Ace Ventura
PY212 Lecture 25 Interference and Diffraction Prof. Tulika Bose 12/3/09 Fun Link: Diffraction with Ace Ventura Summary from last time The wave theory of light is strengthened by the interference and diffraction
More informationDiffraction is the bending of waves around small obstacles and the spreading out of waves past small openings
Diffraction Diffraction is the bending of waves around small obstacles and the spreading out of waves past small openings Diffraction by Pinhead When λ the opening, max diffraction occurs When λ < opening
More informationDiffraction Challenge Problem Solutions
Diffraction Challenge Problem Solutions Problem 1: Measuring the Wavelength of Laser Light Suppose you shine a red laser through a pair of narrow slits (a = 40 μm) separated by a known distance and allow
More informationInterference of Light
Interference of Light Objective To study the interference patterns of light passed through a single and double-slit, a human hair, and compact discs using a laser. Equipment meter stick index card slit
More informationElectromagnetism & Light. Interference & Diffraction
Electromagnetism & Light Interference & Diffraction Your opinion is very important to us. What study material would you recommend for future classes of Phys140/141? A. SmartPhysics alone B. SmartPhysics
More informationChapter 24 - The Wave Nature of Light
Chapter 24 - The Wave Nature of Light Summary Four Consequences of the Wave nature of Light: Diffraction Dispersion Interference Polarization Huygens principle: every point on a wavefront is a source of
More informationDEVIL PHYSICS THE BADDEST CLASS ON CAMPUS IB PHYSICS
DEVIL PHYSICS THE BADDEST CLASS ON CAMPUS IB PHYSICS TSOKOS LESSON 9-2 SINGLE-SLIT DIFFRACTION Essential Idea: Single-slit diffraction occurs when a wave is incident upon a slit of approximately the same
More informationChapter 24. Wave Optics. Wave Optics. The wave nature of light is needed to explain various phenomena
Chapter 24 Wave Optics Wave Optics The wave nature of light is needed to explain various phenomena Interference Diffraction Polarization The particle nature of light was the basis for ray (geometric) optics
More informationAP* Optics Free Response Questions
AP* Optics Free Response Questions 1978 Q5 MIRRORS An object 6 centimeters high is placed 30 centimeters from a concave mirror of focal length 10 centimeters as shown above. (a) On the diagram above, locate
More informationChapter 2: Wave Optics
Chapter : Wave Optics P-1. We can write a plane wave with the z axis taken in the direction of the wave vector k as u(,) r t Acos tkzarg( A) As c /, T 1/ and k / we can rewrite the plane wave as t z u(,)
More informationLecture 4 Recap of PHYS110-1 lecture Physical Optics - 4 lectures EM spectrum and colour Light sources Interference and diffraction Polarization
Lecture 4 Recap of PHYS110-1 lecture Physical Optics - 4 lectures EM spectrum and colour Light sources Interference and diffraction Polarization Lens Aberrations - 3 lectures Spherical aberrations Coma,
More informationChapter 38. Diffraction Patterns and Polarization
Chapter 38 Diffraction Patterns and Polarization Diffraction Light of wavelength comparable to or larger than the width of a slit spreads out in all forward directions upon passing through the slit This
More informationConcepTest PowerPoints
ConcepTest PowerPoints Chapter 24 Physics: Principles with Applications, 6 th edition Giancoli 2005 Pearson Prentice Hall This work is protected by United States copyright laws and is provided solely for
More informationUnit-22 Interference and Diffraction
Unit-22 Interference and iffraction Objective: In this experiment, we used single-slit, double-slit, circular hole and grating to measure the wavelength of laser. Apparatus: Optical track, diode laser,
More informationLecture Wave Optics. Physics Help Q&A: tutor.leiacademy.org
Lecture 1202 Wave Optics Physics Help Q&A: tutor.leiacademy.org Total Internal Reflection A phenomenon called total internal reflectioncan occur when light is directed from a medium having a given index
More informationPhysics 214 Midterm Fall 2003 Form A
1. A ray of light is incident at the center of the flat circular surface of a hemispherical glass object as shown in the figure. The refracted ray A. emerges from the glass bent at an angle θ 2 with respect
More informationDiffraction at a single slit and double slit Measurement of the diameter of a hair
Diffraction at a single slit and double slit Measurement of the diameter of a hair AREEJ AL JARB Background... 3 Objects of the experiments 4 Principles Single slit... 4 Double slit.. 6 Setup. 7 Procedure
More informationReflections from a thin film
Reflections from a thin film l Part of the wave reflects from the top surface and part from the bottom surface l The part that reflects from the top surface has a 180 o phase change while the part that
More informationPhysics 1C, Summer 2011 (Session 1) Practice Midterm 2 (50+4 points) Solutions
Physics 1C, Summer 2011 (Session 1) Practice Midterm 2 (50+4 points) s Problem 1 (5x2 = 10 points) Label the following statements as True or False, with a one- or two-sentence explanation for why you chose
More informationPhysics Midterm I
Phys121 - February 6, 2009 1 Physics 121 - Midterm I Last Name First Name Student Number Signature Tutorial T.A. (circle one): Ricky Chu Firuz Demir Maysam Emadi Alireza Jojjati Answer ALL 10 questions.
More informationSingle Slit Diffraction *
OpenStax-CNX module: m42515 1 Single Slit Diffraction * OpenStax This work is produced by OpenStax-CNX and licensed under the Creative Commons Attribution License 3.0 Discuss the single slit diraction
More informationLECTURE 26: Interference ANNOUNCEMENT. Interference. Interference: Phase Differences
ANNOUNCEMENT *Exam : Friday December 4, 0, 8 AM 0 AM *Location: Elliot Hall of Music *Covers all readings, lectures, homework from Chapters 9 through 33. *The exam will be multiple choice. Be sure to bring
More informationA 4. An electromagnetic wave travelling through a transparent medium is given by y. in S units. Then what is the refractive index of the medium?
SECTION (A) : PRINCIPLE OF SUPERPOSITION, PATH DIFFERENCE, WAVEFRONTS, AND COHERENCE A 1. Two sources of intensity I & 4I are used in an interference experiment. Find the intensity at points where the
More informationChapter 24. Wave Optics
Chapter 24 Wave Optics Diffraction Huygen s principle requires that the waves spread out after they pass through slits This spreading out of light from its initial line of travel is called diffraction
More informationDiffraction and Interference of Plane Light Waves
PHY 92 Diffraction and Interference of Plane Light Waves Diffraction and Interference of Plane Light Waves Introduction In this experiment you will become familiar with diffraction patterns created when
More informationPHY132 Introduction to Physics II Class 5 Outline:
PHY132 Introduction to Physics II Class 5 Outline: Ch. 22, sections 22.1-22.4 (Note we are skipping sections 22.5 and 22.6 in this course) Light and Optics Double-Slit Interference The Diffraction Grating
More informationChapter 36 Diffraction
Chapter 36 Diffraction In Chapter 35, we saw how light beams passing through different slits can interfere with each other and how a beam after passing through a single slit flares diffracts in Young's
More informationUnit 4 Wave Theory of Light. Wave Behaviour
Lesson43b.notebook February 06, 2014 Unit 4 Wave Theory of Light Wave Behaviour Today's goal: I can explain wave behaviour with; barriers, different mediums, etc... and explain how they relate to real
More informationPHYSICS 116 INTERFERENCE AND DIFFRACTION
Name Date Lab Time Lab TA PHYSICS 116 INTERFERENCE AND DIFFRACTION IMPORTANT SAFETY NOTE: PARTS OF THIS LAB INVOLVE THE USE OF HELIUM-NEON LASERS. THESE LASERS WILL NOT BURN YOUR SKIN BUT CAN CAUSE EYE
More informationFor more info
Huygens Principle:- Wave-front of a wave, at any instant, is defined as the locus of all the particles in the medium which are being disturbed at the same instant of time and are in the same phase of vibration.
More informationCOHERENCE AND INTERFERENCE
COHERENCE AND INTERFERENCE - An interference experiment makes use of coherent waves. The phase shift (Δφ tot ) between the two coherent waves that interfere at any point of screen (where one observes the
More informationInterference, Diffraction & Polarization
Interference, Diffraction & Polarization PHY232 Remco Zegers zegers@nscl.msu.edu Room W109 cyclotron building http://www.nscl.msu.edu/~zegers/phy232.html light as waves so far, light has been treated as
More informationmywbut.com Diffraction
Diffraction If an opaque obstacle (or aperture) is placed between a source of light and screen, a sufficiently distinct shadow of opaque (or an illuminated aperture) is obtained on the screen.this shows
More informationDEVIL PHYSICS THE BADDEST CLASS ON CAMPUS IB PHYSICS
DEVIL PHYSICS THE BADDEST CLASS ON CAMPUS IB PHYSICS TSOKOS LESSON 4-7 DIFFRACTION Assessment Statements AHL Topic 11.3. and SL Option A-4 Diffraction: 11.3.1. Sketch the variation with angle of diffraction
More informationLecture 41: WED 29 APR
Physics 2102 Jonathan Dowling Lecture 41: WED 29 APR Ch. 36: Diffraction PHYS 2102-2 FINAL 5:30-7:30PM FRI 08 MAY COATES 143 1/2 ON NEW MATERIAL 1/2 ON OLD MATERIAL Old Formula Sheet: http://www.phys.lsu.edu/classes/
More informationWave Optics. Physics 2B. If two waves exist at the same point in space at the same time, they will interfere with each other.
Physics 2B Wave Optics Interference If two waves exist at the same point in space at the same time, they will interfere with each other. Interference Superposition Principle for Waves The Principle of
More informationCase I: Thin film of uniform thickness:
Interference in Thin Films The film of transparent material like a drop of oil spread on the surface of water, show brilliant colours when exposed to an extended source of light. This phenomenon can be
More informationInterference and Diffraction of Light
Name Date Time to Complete h m Partner Course/ Section / Grade Interference and Diffraction of Light Reflection by mirrors and refraction by prisms and lenses can be analyzed using the simple ray model
More information22.4. (a) (b) (c) (d)
mλl 22.2. Because ym = increasing λ and L increases the fringe spacing. Increasing d decreases the fringe d spacing. Submerging the experiment in water decreases λ and decreases the fringe spacing. So
More informationMDHS Science Department SPH 4U - Student Goal Tracking Sheet
Name: Unit name: Wave Nature of light Goals for this unit: MDHS Science Department SPH 4U - Student Goal Tracking Sheet 1) I can explain wave behaviour and apply the properties to the Wave Theory of Light.
More informationPhysics 123 Optics Review
Physics 123 Optics Review I. Definitions & Facts concave converging convex diverging real image virtual image real object virtual object upright inverted dispersion nearsighted, farsighted near point,
More information