Michelson Interferometer

Item Code: SK025

Principle and Working:

When a coherent light beam enters into beam splitter, it is divided into two parts, thus two beams travel in different directions, are reflected into each other through two mirrors forming interference patterns when they are combined and superimposed. In this setup the wavelength of He-Ne Laser is measured using equation:

... λ=2.L/m

Where L is the total displacement and m is the number of intensity maxima counted.




  • High quality optics (flatness λ /8).
  • Highly stable Interferometer body (weight 7.8 Kg approx).
  • 3 Knurled screw for easy mirror adjustment.
  • Modern & user friendly design (compatible with different light sources).
  • Gear arrangement provides Least count 0.0001 mm.
  • 4 Levelling screws for height adjustment.
  • He-Ne Laser with built-in supply.

Learning Objectives/experiments

  • To determine the wave length of monochromatic light (using He- Ne laser).
  • Moveable mirror : Range 10 – 0 – 10mm
  • Course knob : Least count 0.01 mm,
  • Micro meter fine : Least count 0.0001mm,
  • Beam splitter : Rectangular, size 50 x 39 x 7mm, R/T% 50/50, Flatness λ/8 (at 632mm)
  • Compensator : Rectangular, size 50 x 39 x 7mm, Flatness λ/8 (at 632mm)
  • Mirror : Circular, 2 nos., dimension 30 x 10mm
  • Dimension : 290 x 210 x 230mm (Lx W x H)
  • Laser : He-Ne Laser (632mm), Power 2 mW, Beam spot 2.5mm, current 4mA ~ 6mA, Dimension 300 x 62 x 82mm, Weight 1.5 kg (approx.)
  • Beam expender : Microscope objective, 10x Lab jack : 320 x 220mm
  • 1 Michelson Interferometer
  • 1 He-Ne Laser
  • 1 Beam Expender with holder (SK025)
  • 1 Object screen with Cylindrical base (SK025)
  • 1 Lab jack (SK025)
  • Interference.
  • Wave length.
  • Coherent sources.
  • Superposition.
  • Virtual light source