Polarization by quarter-wave plate

Item Code: SK175

Working and Principle :

A wave plate or retarder is an optical device that alters the polarization state of a light beam traveling through it.

In the present setup, halogen light source with yellow light filter passes through a polarizer to produce linear polarized light. This polarized light then falls on a quarter wave plate λ/4. The emergent light passes through analyser. It is investigated at different angles of λ/4 plate ( 0°, 30°, 45°, 60° and 90°) between the optic axis of the wave plate and the direction of the incident light. The light intensity can be investigated with the analyser over the range -90° to +90°. At 0° and 90° of λ/4 with respect to optic axis, the transmitted light is linearly polarized, at 45° it is circularly polarized, and at 30° and 60° it is elliptically polarized.




  • Halogen light source (35W) with focussing arrangement.
  • Saddle can hold rod from 8 to 15mm.
  • Precise measurement using Data logger & light sensor with Graph analyser software.
  • Heavy, rigid and stable Triangular Optical bench (made of Al extrusion)
  • Height and level adjustment screws (made of SS)
  • Data logger can collect 1,00,000 samples per sec.

Learning Objectives/experiments

  • To measure the light intensity of plane polarised light as a function of the analyzer position.
  • To study the polarization of light by quarter wave plate.
  • To study the polarization of light by two quarter wave plate.
  • Produce circularly polarized light using quatre wave plate
  • Light sensor : Range 0 – 600 Lx, resolution 0.15 Lx Range 0 – 6000 Lx, resolution 1.5 Lx Range 0 – 150K Lx, resolution 37 Lx
  • Accuracy : + 4% over entire range
  • Dataloger : Up to 100K SPS, memory capacity 800K sample, Li polymer rechargeable battery, 6 in-built sensor, 4 ext. sensor port (60+ sensor available), connectivity port micro USB, 90.2 x 90.2 x 20mm(LxWxH), 120gm
  • Halogen lamp : 12 V, 35 W, horizontal filament,
  • Optical bench : Al exclusion, L=1 mtr., Triangular shape with end stop, 4 point levelling (SS screw)
  • Transversal slider : 25 – 0 – 25mm, LC 0.01mm,
  • Polarizer : Angle (0 + 90°), LC 1°, Aperture 21mm, Frame 130mm, Rod 10 mm
  • Quarter wave plate: Circular polarized Angle (0 + 90°), LC 1°, Aperture 21mm, Frame 130mm, Rod 10mm
  • Colour filter : Yellow (light) 505 – 515 nm, Dia. 25-30mm
  • Fixed slider : Al Extrusion, Base width 50mm, H 115mm
  • Power supply : 230V operated, output, 3,4,5,6,8,10,12,14V DC is full wave rectified, unsmoothed & unregulated, thermal reset switch.
  • 1 Optical bench Triangular
  • 1 Transversal slider
  • 1 Halogen light source
  • 2 Polarizer / Analyzer
  • 2 Quarter wave plate
  • 1 Light sensor
  • 1 Data logger
  • 1 Light sensor holder
  • 1 Power supply
  • 1 Yellow light filter
  • 4 Fixed saddle
  • 1 Software CD (MiLAB)
  • 1 Fixed slider (large width)
  • 1 Sensor cable (mini USB)
  • 1 Power cord
  • Polarization
  • Malus law
  • Polarizer, Analyser
  • Half-wave plate
  • Plane of polarization