Collection: Half Waveplate

A half-wave plate, also known as a λ/2 waveplate (lambda over two), is another type of waveplate used to manipulate the polarization state of light. Here's a breakdown of its function and how it compares to a quarter-wave plate:


  • A half-wave plate introduces a specific phase difference of precisely one-half wavelength (π) between the two orthogonal polarization components (fast and slow axes) of the light wave passing through it.

Comparison to Quarter-Wave Plate:

  • The key difference between a half-wave plate and a quarter-wave plate lies in the amount of phase difference they introduce:
    • Quarter-Wave Plate: Introduces a π/2 phase difference (one-quarter wavelength).
    • Half-Wave Plate: Introduces a π phase difference (one-half wavelength).

Impact on Light:

  • Due to this specific phase difference, a half-wave plate can manipulate light polarization in various ways:

    • Rotating Linear Polarization: A primary function of a half-wave plate is to rotate the plane of linearly polarized light. By introducing a π phase difference, the half-wave plate effectively rotates the existing linear polarization by 90 degrees relative to its initial orientation.
    • Converting Between Linear Polarizations: Depending on the initial orientation of the incoming linearly polarized light relative to the waveplate's fast axis, it can convert the polarization state from horizontal to vertical or vice versa.


Half-wave plates find applications in various optics scenarios where control of linear polarization is crucial:

  • Polarization Rotation: They are commonly used to rotate the polarization of laser beams or other light sources for specific needs in optical setups.
  • Elliptical Polarization Conversion: In combination with other waveplates or polarizers, half-wave plates can be used to convert light into elliptically polarized states.
  • Variable Ratio Beamsplitters: When used in conjunction with a polarizer, a half-wave plate can create a variable ratio beamsplitter, allowing control over the intensity ratio of the two outgoing beams.
Half Waveplate

103 products

Message us