Malus Law OE-7032


The Malus Law helps to understand polarization properties of light. It can also be used to study the light intensity relation of polarizer-analyzer. This apparatus comprises of a diode laser (as a light source), a polarizer, an analyzer assembly and a pinhole photo detector with output measurement unit.

Malus law of polarization is verified by showing that the intensity of light passed through two polarizers depend on the square of cosine value of the angle between the two polarizer axis. Laser light is used in this experiment because it’s wavelength is almost completely extinguished by the crossed polarizers. The laser beam travelling through a polarizer is observed as a function of the orientation of the polarizer. With a second polarizer the relative orientation of the polarizers is determined. The transmitted light is measured by a photo detector and the Malus Law can be verified.


Experiment Performed

  • Verification of Malus law
  • To measure the light intensity of plane polarized light as a function of the analyzer position
  • To study the polarization properties of light



  • All components are made out of anodized aluminum and stainless steel to avoid corrosion
  • Holders with adjustable height and compatible in optical rail
  • Graduated circular degree scale of analyzer and polarizer from 0 to 360°
  • Polarizers are good quality
  • Photo detector is high sensitive









Experimental set up Contain Quantity
Optical rail with stands length 1000 mm

Kinematic laser mount

Polarizer with rotation mount

Diode laser < 5mW (650nm or 532nm)

Diode laser with power supply

Photo Detector with mount

Photo Detector Current meter