Abstract Magneto-optical (MO) effects, viz. magnetically induced changes in light intensity or polarization upon reflection from or transmission through a magnetic sample, were discovered over a century and a half ago. Initially they played a crucially relevant role in unveiling the fundamentals of electromagnetism and quantum mechanics. A more broad-based relevance and wide-spread use of MO methods, however, remained quite limited until the 1960s due to a lack of suitable, reliable and easy-to-operate light sources. The advent of Laser technology and the availability of other novel light sources led to an enormous expansion of MO measurement techniques and applications that continues to this day (see section 1). The here-assembled roadmap article is intended to provide a meaningful survey over many of the most relevant recent developments, advances, and emerging research directions in a rather condensed form, so that readers can easily access a significant overview about this very dynamic research field. While light source technology and other experimental developments were crucial in the establishment of todayâs magneto-optics, progress also relies on an ever-increasing theoretical understanding of MO effects from a quantum mechanical perspective (see section 2), as well as using electromagnetic theory and modelling approaches (see section 3) to enable quantitatively reliable predictions for ever more complex materials, metamaterials, and device geometries. The latest advances in established MO methodologies and especially the utilization of the MO Kerr effect (MOKE) are presented in sections 4 (MOKE spectroscopy), 5 (higher order MOKE effects), 6 (MOKE microscopy), 8 (high sensitivity MOKE), 9 (generalized MO ellipsometry), and 20 (CottonâMouton effect in two-dimensional materials). In addition, MO effects are now being investigated and utilized in spectral ranges, to which they originally seemed completely foreign, as those of synchrotron radiation x-rays (see section 14 on three-dimensional magnetic characterization and section 16 on light beams carrying orbital angular momentum) and, very recently, the terahertz (THz) regime (see section 18 on THz MOKE and section 19 on THz ellipsometry for electron paramagnetic resonance detection). Magneto-optics also demonstrates its strength in a unique way when combined with femtosecond laser pulses (see section 10 on ultrafast MOKE and section 15 on magneto-optics using x-ray free electron lasers), facilitating the very active field of time-resolved MO spectroscopy that enables investigations of phenomena like spin relaxation of non-equilibrium photoexcited carriers, transient modifications of ferromagnetic order, and photo-induced dynamic phase transitions, to name a few. Recent progress in nanoscience and nanotechnology, which is intimately linked to the achieved impressive ability to reliably fabricate materials and functional structures at the nanoscale, now enables the exploitation of strongly enhanced MO effects induced by lightâmatter interaction at the nanoscale (see section 12 on magnetoplasmonics and section 13 on MO metasurfaces). MO effects are also at the very heart of powerful magnetic characterization techniques like Brillouin light scattering and time-resolved pump-probe measurements for the study of spin waves (see section 7), their interactions with acoustic waves (see section 11), and ultra-sensitive magnetic field sensing applications based on nitrogen-vacancy centres in diamond (see section 17). Despite our best attempt to represent the field of magneto-optics accurately and do justice to all its novel developments and its diversity, the research area is so extensive and active that there remains great latitude in deciding what to include in an article of this sort, which in turn means that some areas might not be adequately represented here. However, we feel that the 20 sections that form this 2022 magneto-optics roadmap article, each written by experts in the field and addressing a specific subject on only two pages, provide an accurate snapshot of where this research field stands today. Correspondingly, it should act as a valuable reference point and guideline for emerging research directions in modern magneto-optics, as well as illustrate the directions this research field might take in the foreseeable future.
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The 2023 terahertz science and technology roadmap
Terahertz (THz) radiation encompasses a wide spectral range within the electromagnetic spectrum that extends from microwaves to the far infrared (100 GHzââź30 THz). Within its frequency boundaries exist a broad variety of scientific disciplines that have presented, and continue to present, technical challenges to researchers. During the past 50 years, for instance, the demands of the scientific community have substantially evolved and with a need for advanced instrumentation to support radio astronomy, Earth observation, weather forecasting, security imaging, telecommunications, non-destructive device testing and much more. Furthermore, applications have required an emergence of technology from the laboratory environment to production-scale supply and in-the-field deployments ranging from harsh ground-based locations to deep space. In addressing these requirements, the research and development community has advanced related technology and bridged the transition between electronics and photonics that high frequency operation demands. The multidisciplinary nature of THz work was our stimulus for creating the 2017 THz Science and Technology Roadmap (Dhillon
- NSF-PAR ID:
- 10405547
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- IOP Publishing
- Date Published:
- Journal Name:
- Journal of Physics D: Applied Physics
- Volume:
- 56
- Issue:
- 22
- ISSN:
- 0022-3727
- Page Range / eLocation ID:
- Article No. 223001
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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null (Ed.)The DeepLearningEpilepsyDetectionChallenge: design, implementation, andtestofanewcrowd-sourced AIchallengeecosystem Isabell Kiral*, Subhrajit Roy*, Todd Mummert*, Alan Braz*, Jason Tsay, Jianbin Tang, Umar Asif, Thomas Schaffter, Eren Mehmet, The IBM Epilepsy Consortiumâ , Joseph Picone, Iyad Obeid, Bruno De Assis Marques, Stefan Maetschke, Rania Khalafâ , Michal Rosen-Zviâ , Gustavo Stolovitzkyâ , Mahtab Mirmomeniâ , Stefan Harrerâ * These authors contributed equally to this work â Corresponding authors: rkhalaf@us.ibm.com, rosen@il.ibm.com, gustavo@us.ibm.com, mahtabm@au1.ibm.com, sharrer@au.ibm.com â Members of the IBM Epilepsy Consortium are listed in the Acknowledgements section J. Picone and I. Obeid are with Temple University, USA. T. Schaffter is with Sage Bionetworks, USA. E. Mehmet is with the University of Illinois at Urbana-Champaign, USA. All other authors are with IBM Research in USA, Israel and Australia. 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Figure 2 shows that participants had a variety of specialisations, including some that are in no way related to data science, software engineering, or neuroscience. No participant had deep knowledge and experience in data science, software engineering and neuroscience. Conclusion Given the growing complexity of data science problems and increasing dataset sizes, in order to solve these problems, it is imperative to enable collaboration between people with differences in expertise with a focus on inclusiveness and having a low barrier of entry. We designed, implemented, and tested a challenge platform to address exactly this. Using our platform, we ran a deep-learning challenge for epileptic seizure detection. 87 IBM employees from several business units including but not limited to IBM Research with a variety of skills, including sales and design, participated in this highly technical challenge.more » « less
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This research paper focuses on the effect of recent national events on first-year engineering studentsâ attitudes about their political identity, social welfare, perspectives of diversity, and approaches to social situations. Engineering classrooms and cultures often focus on mastery of content and technical expertise with little prioritization given to integrating social issues into engineering. This depoliticization (i.e., the removal of social issues) in engineering removes the importance of issues related to including diverse individuals in engineering, working in diverse teams, and developing cultural sensitivity. This study resulted from the shift in the national discourse, during the 2016 presidential election, around diversity and identities in and out of the academy. We were collecting interview data as a part of a larger study on students attitudes about diversity in teams. Because these national events could affect studentsâ perceptions of our research topic, we changed a portion of our interviews to discuss national events in science, technology, engineering, and mathematics (STEM) classrooms and how students viewed these events in relation to engineering. We interviewed first-year undergraduate students (n = 12) who indicated large differences of attitudes towards diverse individuals, experiences with diverse team members, and/or residing at the intersection of multiple diversity markers. We asked participants during the Spring of 2017 to reflect on the personal impact of recent national events and how political discussions have or have not been integrated into their STEM classrooms. During interviews students were asked: 1) Have recent national events impacted you in any way? 2) Have national events been discussed in your STEM classes? 3) If so, what was discussed and how was it discussed? 4) Do these conversations have a place in STEM classes? 5) Are there events you wish were discussed that have not been? Inductive coding was used to analyze interviews and develop themes that were audited for quality by the author team. Two preliminary themes emerged from analysis: political awareness and future-self impact. Students expressed awareness of current political events at the local, national and global levels. They recognized personal and social impacts that these events imposed on close friends, family members, and society. However, students were unsure of how to interpret political dialogue as it relates to policy in engineering disciplines and practices. This uncertainty led students to question their future-selves or careers in engineering. As participants continued to discuss their uncertainty, they expressed a desire to make explicit connections between politics and STEM and their eventual careers in STEM. These findings suggest that depoliticization in the classroom results in engineering students having limited consciousness of how political issues are relevant to their field. This disconnect of political discourse in the classroom gives us a better understanding of how engineering students make sense of current national events in the face of depoliticization. By re-politicising STEM classrooms in a way relevant to studentsâ futures, educators can better utilize important dialogues to help students understand how their role as engineers influence society and how the experiences of society can influence their practice of engineering.more » « less
