Current Nanomaterials   Send Orders for Reprints to reprints@benthamscience.ae  60 Current Nanomaterials 2017, 2, 60-74  REVIEW ARTICLE Quantitative Plasmon Polarimetry and Spin Optical Effects in Plasmonics 2405-4623/17 $58.00+.00 © 2017 Bentham Science Publishers Shubham Chandel 1,# , Ankit K. Singh 1,# , Angad Gupta 1 , Subir K. Ray 1 , Jalpa Soni 2 , Partha Mitra 1, * and Nirmalya Ghosh 1, * 1 Department of Physical Sciences,Indian Institute of Science Education and Research (IISER) Kolkata. Mohanpur 741246, India; 2 Department of Physics, University of Gothenburg, Gothenburg 41296, Sweden Abstract: Background:Plasmonics’ dealing with localized surface plasmon resonances in metal na- noparticles (nanostructures) and planar metal-dielectric interfaces is a rapidly developing field and is under recent intensive investigations owing to fundamental interests and numerous potential applica- tions. In this regard, the polarization properties of scattered light from plasmonic systems are of para- mount importance for gaining fundamental understanding on a number of interesting and intricate po- larization optical effects and for their potential applications. Coupling and inter-conversion between the spin (SAM, circular / elliptical polarization) and orbital angular momentum (OAM, phase vortex) degrees of freedom of light leading to the so-called spin orbit interaction (SOI) of light, is one such intriguing spin (polarization) optical effect that has recently been observed in diverse plasmonic sys- tems. These have received particular attention because of their potential applications towards devel- opment of novel spin-controlled nanophotonic devices. Objective: Here, we briefly review the basic concepts of SOI, the resulting spin optical effects and their manifestations in diverse nano-plasmonic systems. Method: Mueller matrix spectroscopic system is developed and utilized for probing and tuning spin- dependent plasmonics effects. Results: We provide illustrative results on controlled enhancement of the SOI effects in plasmonic nanostructures. The specifics of a novel dark field Mueller matrix spectroscopic experimental system and the representative results of studies using this system on the SOI and other spin-based plasmonics effects are presented. Conclusion: The implications of these results towards spin-controlled photonic applications are dis- cussed. A R T I C L E H I S T O R Y Received: April 05, 2017 Revised: May 29, 2017 Accepted: June 19, 2017 DOI: 10.2174/2405461502666170629141329 Keywords: Plasmonics, plamon resonance, spin orbit interaction, spin hall effect of light, polarimetry, Fano resonance. 1. INTRODUCTION Interaction of light with noble metal nanoparticles and nanostructures have attracted considerable current interest due to their unique optical properties governed by the so- called surface plasmon resonance effects [1, 2]. The surface plasmons can either be propagating, for instance at planar metal-dielectric interfaces, or localized as in the case of met- al nanoparticles / nanostructures, leading to strong enhance- ment of local electromagnetic fields. The localized plasmon resonances, due to the inherent sensitivity of the distinctive spectral (wavelength dependent) characteristics towards local dielectric environment, are being pursued for numerous prac- tical applications which include, ultra-high sensitive chemi- cal and biomedical sensing, bio-molecular manipulation, *Address correspondence to these authors at the Department of Physical Sciences, Indian Institute of Science Education and Research (IISER) Kol- kata, Nadia, India; Tel/Fax: +91 33 2587 3020; E-mails: nghosh@iiserkol.ac.in; pmitra@iiserkol.ac.in  # The authors contributed equally to this work. labeling, detection, contrast enhancement in optical imaging, surface enhanced spectroscopy (Raman and fluorescence), development of novel nano optical devices, optical infor- mation processing, data storage and so forth [3-9]. A number of intriguing fundamental effects associated with the interac- tion of light with plasmonic nanostructures have also been observed recently. Spin orbit interaction (SOI) and Spin Hall effect (SHE) of light [10-17], Goos–Hänchen (GH) and Im- bert–Fedorov (IF) shifts [18, 19], helicity-independent trans- verse spin and spin (polarization) dependent transverse mo- mentum [12, 20], spin-momentum locking and quantum spin hall effect [12, 21], spin controlled uni-directional excitation of surface modes, optical analogue of quantum weak meas- urements in plasmonic structures [22], coupled plasmons and plasmonic Fano resonances [23, 24], are some of the intricate plasmonic effects. Since, polarization state of light plays an important role in the light-matter interactions leading to most of these aforementioned effects, detailed knowledge on the polarization transformation is crucial for fundamental under- standing of the effects. Acquisition of complete polarization information from plasmonic nanostructures and its analysis /