1

Diffraction is the bending of light when light encounters an obstacle of a size which is in the

range of the wavelength of light.

https://en.wikipedia.org/wiki/Diffraction

Supplementary Diffraction Lecture

2

Diffraction

https://sites.google.com/site/apphysics1online/unit-5-simple-harmonic-motion/3-wave-interference?tmpl=%2Fsystem%2Fapp%2Ftemplates%2Fprint%2F&showPrintDialog=1

Wavefronts

Waves

3

https://en.wikipedia.org/wiki/Huygens–Fresnel_principle

Diffraction of a plane wave when the slit width is the size of the wavelength.

Huygens-Fresnel Principle -- Diffraction

Narrow Slit Case

4

IncomingSpherical

Wave

http://www.marcuswinter.de/wp-login.php?redirect_to=http%3A%2F%2Fwww.marcuswinter.de%2Farchives%2F1351

Wide Slit Case

Huygens-Fresnel Principle -- Diffraction

5

Huygens-Fresnel Principle -- Refraction

https://courses.lumenlearning.com/boundless-physics/chapter/diffraction/

1n

2n

6

http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/dslit.html

Double Slit Diffraction

7

https://courses.lumenlearning.com/boundless-physics/chapter/diffraction/

Double Slit Diffraction Pattern

8

http://www.mysearch.org.uk/website1/html/464.Behaviour.html

Double Slit Diffraction Pattern

9

https://www.quora.com/What-are-Fresnel-and-Fraunhofer-diffraction

Fraunhofer diffraction occurs when ,

where W is the aperature or slit size, is the wavelengthand L is the distance from the aperature or slit.

2

1W

L

10

http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/fraungeo.html

Fraunhofer Diffraction (Far Field)

11

Multiple Slit Diffraction – Multiple Orders

From: Eugene Hecht, Optics, 4th edition,Addison Wesley (Pearson Education Inc.)

2002, Chapter 10, Figure 19.15, page 461.

Single wavelength shown

m = 0

m = 1

m = 2

12

A diffraction grating is an optical component, which separates (disperses) polychromatic

light into its constituent wavelengths (i.e., colors). Polychromatic light incident on the grating is dispersed so that each wavelength is reflected from the grating at a slightly different angle. The dispersion arises from the wavefront division and interference of the incident radiation from the periodic structure of the grating.

https://andor.oxinst.com/learning/view/article/diffraction-gratings

Diffraction Gratings

Diffraction Grating sheetwith 13,500 lines/inch

13

https://andor.oxinst.com/learning/view/article/diffraction-gratings

Diffraction Grating – Multiple Orders

14

Transmission Grating & Reflection Grating

https://www.globalspec.com/learnmore/optics_optical_components/optical_components/diffraction_gratings

15

https://www.youtube.com/watch?v=OHTpxHxuAhY

16

https://www.osapublishing.org/viewmedia.cfm?r=1&rwjcode=ao&uri=ao-18-16-2834&html=true

Littrow-Type Grating Optical Demultiplexer

InputFiber

17