Use of λ/4 phase plate in laser conoscopic method

Possibilities of laser conoscopic method expanded due to the introduction of λ/4 phase plate in the optical system. The introduction of λ/4 phase plate with known optical sign leads to changes the conoscopic pattern of the investigated crystal plate. Changes conoscopic patterns allow to quickly and reliably determine the optical sign, the presence of optical activity of the crystal, the direction of rotation of the plane of polarization of radiation in optically active crystal for crystal plates of any thickness and any value of the specific rotation. In addition, changes conoscopic pattern of a crystal of known optical sign indicate the location of the optical axis in the plane of the input face the λ/4 phase plate.