John Dudley
Research & Other Activities
Speaking & Talks
I am happy to speak on various topics to diverse audiences, from non-specialist to experts. I am quite busy but please email me and we can see if we can work something out and find a date that suits. Talks can be given either in English or in French.
Topics for Talks
The talks below cover different aspects of my research activities and other interests. They can be given independently or some aspects can be combined together.
Light, Lasers and the Nobel prize
Although we often think of laser applications in photonics as being related more closely to engineering than to basic science, the development of the laser in fact traces a path that runs parallel to basic research in many areas of physics, and intersects with the recognition of many of the pioneers of optics through the Nobel Prize. This talk describes some of the key historical contributions to our modern understanding of light and lasers, and describes some of the background to a number of key Nobel Prizes in these areas.
Ultrafast Measurements and Extreme Events in Nonlinear Fibre Optics
The year 2021 represents 60 years since the birth of nonlinear optics, and with continued developments in sources, materials, and waveguides, the field is more active than ever. An area of much recent interest has focused on studying extreme nonlinear pulse propagation in optical fibre and fibre lasers, and experiments have revealed a rich landscape of complex interactions due to the interplay of nonlinearity, dispersion and dissipation. In the past, however, these dynamics have not been able to be measured completely because of experimental limitations, but new techniques have now opened up the possibility to analyze a range of novel nonlinear processes, including the generation of spontaneous "rogue wave" events with analogies to the giant and destructive waves on the surface of the ocean. After giving a general introduction to the field and an overview of the measurement techniques used, we will discuss a range of recent results in both fibre propagation and fibre laser systems. We will also describe how tools from artificial intelligence such as neural networks are providing exciting new methodologies to study and understand such complex dynamics.
Extreme events in nature, rogue wave in optics
A central challenge in understanding extreme events in physics is to develop rigorous models linking the complex generation dynamics and the associated statistical behaviour. Quantitative studies of extreme phenomena, however, are often hampered in two ways: (i) the intrinsic scarcity of the events under study and (ii) the fact that such events often appear in environments where measurements are difficult. A particular case of interest concerns the infamous oceanic rogue or freak waves that have been associated with many catastrophic maritime disasters. Studying rogue waves under controlled conditions is problematic, and the phenomenon remains a subject of intensive research. On the other hand, there are many qualitative and quantitative links between wave propagation in optics and in hydrodynamics, because a nonlinearly-induced refractive index perturbation to an optical material behaves like a moving fluid and is described mathematically by the same propagation equation as nonlinear waves on deep water. In this context, significant experiments have been reported in optics over the last two years, where advanced measurement techniques have been used to quantify the appearance of extreme localised optical fields that have been termed "optical rogue waves". The analogy between the appearance of localized structures in optics and the rogue waves on the ocean's surface is both intriguing and attractive, as it opens up possibilities to explore the extreme value dynamics in a convenient benchtop optical environment. The purpose of this talk will be to discuss these results that have been obtained in optics, and to consider both the similarities and the differences with oceanic rogue wave counterparts. The talk will provide suitable introduction to specialist aspects of ocean physics and optics, and will be accessible to non-specialists.
Light on nonlinearity: New waveguides, new nonlinearities, new directions in ultrafast science
The fields of laser source development and nonlinear optics have been natural partners now for over half a century, and this partnership has impacted on all fields of science and technology. The purpose of this talk is to survey a broad selection of new breakthroughs in nonlinear optics. We will discuss in particular how developments in new materials and new classes of photonic waveguide are leading to fundamental advances in the understanding of nonlinear light-matter interactions and new applications across many different fields. We focus especially on development in ultrafast nonlinear photonics, and consider how these advances are motivating unexpected new directions of research with surprising applications for other fields of physics.
Complex pulses and new physics: complete pulse measurements in ultrafast optics
Since its first development twenty years ago, frequency resolved optical gating (FROG) has become an essential characterisation tool in ultrafast optics, and its many success stories are now well-known. The use of FROG contributed crucially to the development of optimized sub-10 fs lasers producing transform limited pulses, and has motivated a continual search for both related and complementary techniques extending complete pulse characterisation into new wavelength regimes and measuring temporal pulses of ever-decreasing duration. The purpose of this talk is to focus on the particular successes that FROG has had in characterizing pulses far from the transform limit associated with various classes of nonlinear pulse propagation. Although characterising complex optical fields using FROG has posed a variety of experimental challenges, these have all been met and the results obtained have opened up new directions of research in nonlinear optics. Amongst the results that will be surveyed are: the first results that directly confirmed soliton propagation and optical shock dynamics in optical fiber, measurements of self-similar fiber propagation that have opened up a new field of research in the study of optical "similariton" physics, measurements of novel classes of two-dimensional localized fields analogous to the high intensity extreme rogue waves observed in hydrodynamics.
Nonlinear Fibre Optics and Supercontinuum Generation Tutorial (can be adapted to between 1-3 hours)
This talk provides a comprehensive tutorial/short course into the physics of nonlinear fibre optics and supercontinuum generation in optical fiber. Both fundamental aspects and applications are considered. Keywords includee: supercontinuum physics, soliton fission, Raman solitons, modulation instability, dispersive waves, self-similar evolution, optical fiber amplifiers, pulse compression, frequency conversion and regeneration, rogue waves. If time permits and if computing facilities are available, participants can also be provided with training in numerical methods allowing the integration of the generalised nonlinear Schrodinger equation.
Unexpected connections in pure and applied research
There is currently intense international debate concerning optimal ways to manage interactions between fundamental and applied research. However, although there is sometimes a tendency to view this as a modern problem, the same issues have occurred frequently during the history of scientific development. This talk will review some particular examples from nonlinear science, discussing unappreciated aspects of research in nonlinear soliton physics, spanning the 19th century laying of the transatlantic cable, the Manhattan Project, the 2005 and 2009 Nobel Prizes in physics, the latest techniques in medical diagnostics and the detection of extra-solar planets. We will also see how these developments are leading to dramatic developments in nonlinear optics and fundamental advances in the understanding of nonlinear light - matter interactions, new approaches for ultrafast laser design, and leading to some surprising applications in other fields of physics. The talk will consider technical aspects of wave propagation and nonlinear photonics, but will be sprinkled with historical anecdotes and thus will be suitable for a general audience.
Unexpected Ultrafast
Recent years have seen tremendous progress in the ability to generate and shape optical fields on ultrafast timescales. This talk will provide an overview on research on these topics, focusing on two specific areas: (i) the generation of femtosecond accelerating beams for micro- and nano- machining of glass, silicon, diamond and graphene; (ii) the use of advanced real-time techniques to study optical instabilities and the use of optical fields to create analogues to the infamous and destructive "rogue waves" on the surface of the ocean.
International Outreach with UNESCO - the International Year of Light 2015
A partnership of over 100 scientific societies and organizations from more than 85 countries successfully led an initiative to have the year 2015 declared the International Year of Light at the United Nations General Assembly. The International Year of Light saw thousands of academic and industry organizations around the world join forces to raise awareness of the many ways in which photonics impact our lives in areas such as energy, education, climate-change, and health. These efforts have resulted in IYL 2015 being amongst the most successful and visible of any of UNESCO's international observances, with activities involving millions of people in more than 100 countries worldwide. This talk provides an overview of the process involved in working with an international organisation such as UNESCO, highlighting also important aspects of how scientists can effectively communicate ideas with decision-makers and politicians. It will also provide practical advice about how such a large multi-partner initiative can be run, including discussions of organisation, delegating responsibilities on an international level, and fundraising.
Surviving in Science: what they don't tell you about careers in research!
Obtaining a PhD is an important and significant achievement in your life, but it is really only the start! A successful career in research requires not only a PhD but also many other skills in multiple areas: from an appreciation of the broader aims of basic science, to writing and communication, to management and leadership. When starting out, the breadth of this required expertise can seem daunting, but the aim of this presentation will be to try to provide simple and practical advice to help early-career researchers to build and enjoy a long term career in photonics. Amongst topics to be covered will be: networking; career options; paper writing and conferences; ethics; transitioning from student to postdoc to team leader; funding opportunities etc.
Science Communication for Early Career Researchers
Being able to effectively communicate science to different audiences is essential for all researchers, but is especially important for students and recent graduates looking to establish a career in academia or industry. This Webinar will provide a general overview of the Science Communication ecosystem, from tips on how to effectively communicate the key points of your research to a specialist audience, to more general issues on how to engage with the public and organize outreach events. It will also describe some career opportunities in Science Communication. This talk can be adapted from between 30 minutes to 4 hours! A Q&A session is also an integral part of the topic, and the audience is invited to submit questions in advance.
A Brief History of Light
Light is a fantastic topic to excite the imagination and to stimulate interest in science for students of all ages. With suitable preparation, I can propose a 60-90 minute public lecture discussing light from the big bang to modern applications in communications, involving live demonstrations of all kinds illustrating the principles of (among other things) forensic science, cold atoms, quantum mechanics, light sabers, levitation and more ... This lecture requires local support but a detailed list of possible demonstrations and requirements can be provided. The idea here is to leave the host university with a copy of the slides used so that similar talks can be delivered locally to schools, beginning students etc.
Science, Skepticism and Firewalking
Firewalking describes the practice of walking barefoot over a bed of hot embers or sometimes over hot stones. Practiced by many cultures, it has often been associated with supernatural powers and carried out as a test of one's faith. However, any link between firewalking and supernatural, paranormal or new age phenomena is complete nonsense, and the truth lies in the science. There are a number of factors at play but in essence, although a bed of glowing embers may look terrifying and the internal temperature of the embers may well be over 500 C, the surface temperature can be considerably lower, and the low thermal conductivity of the surface layer results in minimal heat transfer provided one is in brief enough contact. I have been giving lectures and demonstrations of firewalking since 1997 after being "trained" by the New Zealand firewalking legend John Campbell. A lecture and demonstration go hand in hand and the lecture can also give a physicist's critique of pseudoscience and irrational beliefs in general.
Selected Research Publications
Teaching & Outreach Publications
Speaking and Talks
Towards a Self-Driving Ultrafast Laser
Light, Lasers, and the Nobel Prize
20 year Activity Report on Twitter!
Instabilities in Dissipative Soliton Lasers characterized using real-time DFT
New paper on Machine Learning in Nonlinear Fibre Optics in Scientific Reports
Real-time measurements in the CNRS 2016 Annual Report
Real Time Measurements of Dissipative Solitons Published in Nature Photonics
Magnified time-domain ghost imaging paper published in APL Photonics
New paper on the universal Peregrine Soliton published in PRL
Real time Modulation Instability paper published in Nature Communications
Institut FEMTO-ST, Université de Franche-Comté-CNRS UMR 6174
15B avenue des Montboucons
F-25030 BESANCON Cedex
Email: john.dudley"at"univ-fcomte.fr
Twitter: @johnmdudley