Polarization rotation: phenomenon where the orientation of polarization plane changes as light passes through certain materials or structures.
Occurs in anisotropic materials (e.g., crystals, liquid crystals, optical waveguides) with direction-dependent properties.
Input polarization plane undergoes rotation when unpolarized or linearly polarized light passes through a rotation-inducing material.
Rotation angle depends on material properties and incident light wavelength (Faraday rotation angle or Verdet constant).
Applications: optical communication systems, optical isolators, magneto-optical devices, and polarization-sensitive detectors.
Different from birefringence (polarization-independent separation of light into orthogonal polarizations).
Polarization rotation controlled by external factors (magnetic field, electric field) depending on the material or device.
Significance in telecommunications, optics, magneto-optics, and material characterization.
2. Principle
• A polarization rotator is an optical
device that rotates the polarization axis
of a linearly polarized light beam by an
angle of choice
• Distance between mirrors is d.
• Laser of wavelength λ at an incident
angle θ.
3.
4. Construction
• Optical Rail (1 meter)
• Fabry-Perot setup (Fixed
Mirror mount with Two
Etalon)
• Movable Mirror
• Diode Laser mount with
Kinematic (5 V) Power
Supply
• Achromatic Lens mount
5. • The phase difference is given by:
𝛿 = ( 2π /λ ) ∆
• Thus, the resultant transmitted light intensity IT
where, I0 is the incident intensity, R is the reflectivity of the mirrors. It can be noticed
that IT varies with 𝛿
6.
7. Applications
• Polarization can be used as an artistic medium to create unique and
visually striking works of art.
• In astronomy an etalon is used to select a single atomic transition for
imaging.
• Polarization can be used in archaeology to study the properties of
ancient materials such as ceramics, glass, and stone.
• Polarization is used in laser-based measurement and sensing systems to
determine physical properties of materials, such as surface roughness
and refractive index.
