EKSMA OPTICS

You are here: Home » Products » Optical Components » Fresnel Rhombs

Due to unequal phase shifts arising in orthogonally polarized components of an incident wave at total internal reflection Fresnel Rhombs are used to alter polarisation type of radiation. They are designed so that two full internal reflections inside a rhomb provide π/2 phase difference between the orthogonally polarized components of radiation. Hence, if there is 45° angle between the polarization of the linearly polarized incident plane, the emerging beam is circularly polarized, i. e. the rhomb effect is similar to that of a quarter-waveplate. Therefore two identical Fresnel rhombs, installed in series, will provide π/2 phase difference similar to that of a half-waveplate, i. e. the device can rotate the beam polarization plane by 90°, leaving the beam direction invariable.