Interferometric Weak Measurement and its applications in Magneto-optics

Panda, Anwesha (2019) Interferometric Weak Measurement and its applications in Magneto-optics. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Anwesha Panda (14MS144)) 14MS144.pdf - Submitted Version Restricted to Repository staff only Download (4MB)

Abstract

The extraordinary concept of weak value amplification and a number of other seemingly counter-intuitive wave phenomena are manifestations of fine interference effects. In this report, we show that weak value amplification naturally arises in the cases of nearly destructive interference between the two orthogonal states of the observable which mimics the corresponding near destructive interference between the eigenstates of the measuring observable as a consequence of nearly mutually orthogonal pre and post selections of the system states. In order to elucidate this, we first experimentally demonstrate a weak measurement concept that uses near destructive interference of two paths of an interferometer having slightly rotated linear polarization states of light. By generating nearly destructive interference between the two paths with small amplitude and phase offsets of the waves, we observe both real and imaginary (respectively) weak value amplification of the small polarization rotation leading to large rotation of the polarization vector orientation and dramatic changes in the circular polarization descriptor fourth Stokes vector element of light, respectively. We go on to demonstrate that the giant enhancement of magneto-optical Kerr rotation, by which we can claim that we have found a non-modulation based and cost-effective magneto-optical Kerr effect (MOKE) measurement. At the end, we show successful weak value amplification of spin Hall shift in magneto-optical sample in both longitudinal and polar MOKE. Our ongoing work is to find out the relation between magneto-optical Kerr rotation and spin Hall shift of light in magnetic material.

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