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arXiv · 1212.6472

High sensitivity differential Magneto-Optical Imaging with a compact Faradaymodulator

Pabitra Mandal·Debanjan Chowdhury·S. S. Banerjee·T. Tamegai
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Abstract

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.

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Pabitra Mandal, Debanjan Chowdhury, S. S. Banerjee, T. Tamegai. 2012-12-28. High sensitivity differential Magneto-Optical Imaging with a compact Faradaymodulator. https://doi.org/10.1063/1.4770128

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