Polymer and magnetic nanoparticle composites with tunable magneto-optical activity: role of nanoparticle dispersion for high verdet constant materials

Pavlopoulos, Nicholas G.; Kang, Kitaek; Holmen, Lindsey N.; Lyons, Nicholas P.; Akhoundi, Farhad; Carothers, Kyle J.; Jenkins, Shelbi L.; Lee, Taeheon; Kochenderfer, T. M.; Phan, Anthony; Phan, David D.; Mackay, Michael E.; Shim, In‐Bo; Char, Kookheon; Peyghambarian, N.; LaComb, Lloyd; Norwood, Robert A.; Pyun, Jeffrey

doi:10.1039/d0tc00077a

Cited by 21 publications

(38 citation statements)

References 49 publications

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“…Although the high optical quality, high laser damage threshold, and low absorptivity of TGG and other inorganic crystals make them ideal for many applications, future magneto-optical technologies may demand the lightness, flexibility, tunability, and processability that are characteristics of many organic materials. Over the past decade, several organic materials have matched or exceeded the magneto-optical performance of TGG by employing a variety of design strategies, including extended conjugation, ,− helical chromophores, , the inclusion of paramagnetic dopants, − and spin-forbidden transitions . To date, the largest Verdet constants reported in organic thin-films are on the order of 10 5 deg T –1 m –1 . ,, However, many high-performance organic Faraday rotators are not of optical quality because they incorporate light-scattering nanoparticles or crystalline domains .…”

Section: Introductionmentioning

confidence: 99%

Large Faraday Rotation in Optical-Quality Phthalocyanine and Porphyrin Thin Films

et al. 2021

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The magneto-optical phenomenon known as Faraday rotation involves the rotation of plane-polarized light as it passes through an optical medium in the presence of an external magnetic field oriented parallel to the direction of light propagation. Faraday rotators find applications in optical isolators and magnetic-field imaging technologies. In recent years, organic thin films comprised of polymeric and small-molecule chromophores have demonstrated Verdet constants, which measure the magnitude of rotation at a given magnetic field strength and material thickness, that exceed those found in conventional inorganic crystals. We report herein the thin-film magnetic circular birefringence (MCB) spectra and maximum Verdet constants of several commercially available and newly synthesized phthalocyanine and porphyrin derivatives. Five of these species achieved maximum Verdet constant magnitudes greater than 10 5 deg T −1 m −1 at wavelengths between 530 and 800 nm. Notably, a newly reported zinc(II) phthalocyanine derivative (ZnPc-OT) reached a Verdet constant of −33 × 10 4 deg T −1 m −1 at 800 nm, which is among the largest reported for an organic material, especially for an opticalquality thin film. The MCB spectra are consistent with resonance-enhanced Faraday rotation in the region of the Q-band electronic transition common to porphyrin and phthalocyanine derivatives, and the Faraday A-term describes the electronic origin of the magneto-optical activity. Overall, we demonstrate that phthalocyanines and porphyrins are a class of rationally designed magnetooptical materials suitable for applications demanding large Verdet constants and high optical quality.

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Section: Introductionmentioning

confidence: 99%

Large Faraday Rotation in Optical-Quality Phthalocyanine and Porphyrin Thin Films

et al. 2021

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“…However, one study has shown that magnetic fields with a magnitude of 20 femtotesla (10 −15 Tesla) can be detectable by instruments using nano-magnetite polymers, which consist of iron (Fe) and cobalt (Co) ( Amirsolaimani et al., 2018 ). Another study found that it is possible to measure magnetic field of femtotesla (10 −15 Tesla) scale power using CoFe 2 O 4 nanocrystals ( Pavlopoulos et al., 2020 ). It has long been argued that the earth's magnetic waves can interfere with the measurement of the brain magnetic field and it has also been maintained that the magnetic field of the earth disturbs the ability to sense the brain's magnetic field.…”

Section: Voltage-gated Channelsmentioning

confidence: 99%

Brain-to-brain communication: the possible role of brain electromagnetic fields (As a Potential Hypothesis)

Hosseini

2021

Heliyon

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Up now, the communication between brains of different humans or animals has been confirmed and confined by the sensory medium and motor facilities of body. Recently, direct brain-to-brain communication (DBBC) outside the conventional five senses has been verified between animals and humans. Nevertheless, no empirical studies or serious discussion have been performed to elucidate the mechanism behind this process. The validation of DBBC has been documented via recording similar pattern of action potentials occurring in the brain cortex of two animals. With regard to action potentials in brain neurons, the magnetic field resulting from the action potentials created in neurons is one of the tools where the brain of one animal can affect the brain of another. It has been shown that different animals, even humans, have the power to understand the magnetic field. Cryptochrome, which exists in the retina and in different regions of the brain, has been confirmed to be able to perceive magnetic fields and convert magnetic fields to action potentials. Recently, iron particles (Fe 3 O 4 ) believed to be functioning as magnets have been found in various parts of the brain, and are postulated as magnetic field receptors. Newly developed supersensitive magnetic sensors made of iron magnets that can sense the brain's magnetic field have suggested the idea that these Fe 3 O 4 particles or magnets may be capable of perceiving the brain's extremely weak magnetic field. The present study suggests that it is possible the extremely week magnetic field in one animal's brain to transmit vital and accurate information to another animal's brain.

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“…11 (a), where the Faraday rotation is measured using a Wollaston prism and a polarized laser diode light source. For more details regarding this setup, the reader can refer to [68]. Once we find a material which has a relatively large Verdet constant, we use it to make various optical sensors.…”

Section: Microscope Design and Performance Analysismentioning

confidence: 99%

Biomedical Optical Sensors

Akhoundi¹

2020

Biological and Medical Physics, Biomedical Engineering

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Polymer and magnetic nanoparticle composites with tunable magneto-optical activity: role of nanoparticle dispersion for high verdet constant materials

Abstract: The critical role of nanoparticle dispersion on Faraday rotator activity was studied, revealing new routes for fabricating “plastic garnets” as low cost alternatives to existing inorganic materials for optical isolation and magnetic sensing.

Cited by 21 publications

References 49 publications

Large Faraday Rotation in Optical-Quality Phthalocyanine and Porphyrin Thin Films

Large Faraday Rotation in Optical-Quality Phthalocyanine and Porphyrin Thin Films

Brain-to-brain communication: the possible role of brain electromagnetic fields (As a Potential Hypothesis)

Biomedical Optical Sensors

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