Rotation of polarization plane of a laser beam by fluid vorticity

The polarization plane of a beam of light experiences angular drag when it traverses a medium rotating about an axis parallel to the direction of the beam. Here, fluid vorticity in a horizontal Rijke tube is used to cause rotation in the polarization plane of a continuous laser beam. The vorticity distribution and acoustic pressure history in the tube have been predicted numerically. The thermo-acoustic phenomenon in the tube has been found to generate the vorticity. A suitable optical arrangement has been used to capture the light intensity variation due to the rotation of the plane of polarization of the beam, and up to 4° of rotation has been observed.