Intracavity polarimeter for measuring small optical anisotropies

Abstract

An intracavity polarimeter for measuring small optical anisotropies is described. It is based on an optically pumped sodium dimer ring laser that supports two counterpropagating, orthogonally polarized modes. The optical anisotropy of an intracavity sample is detected by its effect on the beat frequency between the two modes. An analysis of the noise shows that a phase-retardation sensitivity of 6 X 10-8 rad can be achieved. A preliminary measurement of the Kerr effect in CO 2 is reported.

Observation of transmission enhancement phenomena in a laser resonant cavity

“…It is well known that the lasing properties are extremely sensitive to the change of the resonant cavity. Hence, the lasers can also play the role of a sensor in some measurement techniques [1][2][3][4][5][6][7] . In those techniques which the measured samples are placed directly in the laser cavity 6,7 , the antireflection (AR) coating for the samples was considered to be necessary in order to reduce the reflection loss.…”

Nonlinear Optical Technique for Precise Retardation Measurements

“…Existing ellipsometric techniques allow determining the azimuth of the polarization ellipse to a precision of 10 26 rad [5]. The retardation induced by active components on a light beam can be measured to a precision on the order of l͞10 8 using, for example, an intracavity polarimeter [6] or optical heterodyne techniques [7]. A similar precision in retardation measurements of passive components, however, has been reached only for very particular cases, e.g., for supermirrors with ultralow birefringence [8].…”