%0 Journal Article
%T High sensitivity differential Magneto-Optical Imaging with a compact Faradaymodulator
%A Pabitra Mandal
%A Debanjan Chowdhury
%A S. S. Banerjee
%A T. Tamegai
%J Physics
%D 2012
%I arXiv
%R 10.1063/1.4770128
%X We present here the design of a sensitive Compact Faraday-modulator (CFM) based optical magnetometer for imaging the distribution of weak local magnetic fields inside hysteretic magnetic materials. The system developed has a root mean square (rms) noise level of 50 mG.Hz-1/2 at a full frame rate of 1 frame per second with each frame being of size 512 x 512 pixels. By measuring the local magnetic field distribution in different superconducting samples we show that our magnetometer provides an order of magnitude improvement in the signal to noise (S/N) ratio at low fields as compared to ordinary magneto-optical imaging technique. Moreover, it provides the required sensitivity for imaging the weak magnetization response near a superconducting transition where a number of other imaging techniques are practically unviable. An advantage of our CFM design is that it can be scaled in size to fit into situations with tight space constraints.
%U http://arxiv.org/abs/1212.6472v1