Magnification of a tiny polarisation rotation by a dichroic plate in balanced mode polarimetry

• Published in: Optics communications Vol. 138; no. 4; pp. 249 - 252
• Main Authors: Chauvat, D, Guéna, J, Jacquier, Ph, Lintz, M, Bouchiat, M.A, Plimmer, M.D, Goodwin, C.W
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.1997
• Subjects: 35.10.Wb; 42.10.N; 42.65; 07.60.F
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/S0030-4018(97)00068-0

We demonstrate the magnification of a small rotation angle of the linear polarisation of a laser beam measured with a balanced mode polarimeter. This is performed by a single-pass passive dichroic optical component placed between the sample inducing the rotation and the analyser. We show that in the shot-noise limit the signal-to-noise ratio is conserved while the angle is magnified by a factor K and the intensity attenuated by K 2. Practical realisation is achieved using a dichroic plate for which K = −4.2. This amplification will be valuable for high precision measurements such as atomic Parity Violation tests.