Experiment Description

Experiment

Experiment C04    Study of Interference of Light by Laser

Objectives
  • Determine the slit separation of multiple-slit slide by using laser
  • Compare the results of interference pattern by coarse and fine diffraction grating
  • Study the reflective interference patterns of a diffraction grating and compact discs
  • Estimate the tract pitch of CD-ROM and compare the track pitch with other optical storage devices
Description
In this activity, you will use a laser beam to study the diffraction of light in both transmission and reflection. Diffraction gratings of different number of slits starting from 2 slits will be used. Besides, you will also study the diffraction of light by CD-ROM and determine the pitch of its tracks.

In Experiment 1, you will send a beam of laser through a set of multiple-slit gratings of the same slit separation, beginning with double-slit.

In Experiment 2, you will use both coarse and fine diffraction gratings and study the diffraction pattern of the transmitted light.

In Experiment 3, you will study the reflected light by the diffraction gratings.

In Experiment 4, you will replace the diffraction grating with a CD-ROM and study the diffraction pattern of the reflected light.
Apparatus
"Class 2" laser [1]
laser safety goggles [1 for each mem.]
diffraction grating slide coarse (150 lines per mm) and fine (300 lines per mm) [1 each]
5 cm square multiple-slit slide (2-slit, 3-slit, 4-slit) [1 each]
holder for 5 cm square slide [1]
metre rule [4]
set square [1]
screen [5]
holder for plane mirror [2]
plasticine [1]
wedge [1]
CD-ROM, blank CD-R, CD-RW, DVD, MO [1 each]
laser pointer [1]
halfly written CD-R [1]
Experiment