New invited review paper is online! I wanted to survey the state-of-the-art in fiber plasmonics – for conveniently confining and enhancing light on a fiber tip. As I started working in this field a few years ago, I thought it would have been good to compare systems which, although sharing a platform and an objective, can be quite different from each other. See below!
My work on self-recovering long-range surface plasmons in gold-filled optical fibers was recently published in Phys. Rev. Applied! It’s satisfying to see that my original goal of measuring ultrafast nonlinear plasmonic effects on gold nanowires within optical fibers – which formed the crux of my original Humboldt Fellowship to Jena – has come to fruition. Since my original proposal was written in 2014 there has been quite a lot of great work in this field! One of the greatest problems for plasmonic propagation in nanowires in fibers was that, for small wire diameters, the wires break up, and scatter off light at the gaps. As it turns out, if these wires are inside the core of a waveguide (such as an optical fiber), it’s possible to circumvent this, since most of the scattered light is captured by the waveguide, and then immediately fed back into the plasmon! This process is efficient enough to enable measurements of the nonlinearity of gold (via nonlinear absorption) which crucially requires high peak powers to be maintained. Read the article here.
Hard to believe the first month of 2018 is nearly over! I thought I might include a couple of photos from two events I attended late last year – the IPOS symposium and the SPIE NanoPhotonics Australasia conference in Melbourne, where I had an invited talk. On the last day I attended the CUDOS Frontiers in Nanoplasmonics Workshop, which featured many distinguished international guests, and was a great opportunity to initiate collaborations. Looking forward to the year ahead (at least, the 11 months left…)
Had a great time last week presenting a new-and-improved talk on invisibility at Nerd Nite! As usual this is a great way to engage with the local community, this time at the legendary Friend in Hand in Glebe just down the road from the University of Sydney. The other speaker at the event was world-famous Prof. Peter Kinderman, who was in Sydney for The Big Anxiety Festival, and gave a beautiful talk about the fundamental role of one’s environment and upbringing on mental health, which in his opinion (from what I understand) overshadows the role of genetics. This appears to be a somewhat controversial view that managed to stir up quite a few audience members.
I recommend keeping an eye out for future Nerd Nite events. I’ll definitely be going back for more!
Last Sunday I had the pleasure of presenting at the Science at the Local event in the Blue Mountains. I’m thankful to Hamish Clarke for the invite up to sunny Springwood – despite the sunny day quite a crowd turned up to the local sports club to hear me talk about The Physics of Invisibility. The audience feedback and engagement was impressive, I had many excellent questions and insightful conversations after the talk- there should be a lot more events like this! The other speaker was Bianca Heng, who discussed the controversial science of video-game addiction – there is much more that needs to be understood, especially in the broader context of the relationship between humans and technology. What a day!
Would highly recommend to keep an eye out on future Science at the Local events – see their facebook page to not miss out.
The 28th of April was my last official day at the Leibniz Institute for Photonic Technology (IPHT). I consider myself very lucky to have been a part of this incredible group (shown nostalgically in the black-and-white photograph above) led by Prof. Markus A. Schmidt, covering numerous and diverse fields such as plasmonics, non-linear optics, hybrid photonics, metasurfaces and metamaterials, bio-photonics and sensing (and more!) – all within the optical fiber platform. I thank the Alexander von Humboldt Foundation, which sponsored my fellowship and made me feel at home in Germany from the get-go.
I had a very productive and fun two and a half years, making many friends and connections not only inside IPHT, but also in the neighboring Abbe Center of Photonics and the Fraunhofer Institute, as well as the Max Planck Institutes and Center for Molecular Biomedicine – what an environment! Anyone who visits Jena is immediately impressed by the quality of the infrastructure within the City of Light – and I mean that in terms of human, scientific, and educational resources. Of particular note is the Masters in Photonics Program at the Abbe School of Photonics (at which I had the pleasure of lecturing, overseeing student seminars, and superviseing Masters students), which I believe currently provides the best-value English-language photonics education in the world.
Looking back at my two years at IPHT, I produced four first-author publications (with a few more on the way!), contributing four more as co-author, while still contributing to papers with colleagues in Sydney and Freiburg. Fortunately, the experience gained by the group through my contributions has not been lost, and I am confident that the students I recruited and trained will continue with great success in the years to come!
Ron Fatobene Ando did a fantastic job in performing a systematic analysis of the origin nano-gaps between the metal and the silica fiber wall, which emerge when filling the nanochannels in photonic crystal fibers and modified step-index fibers with metals. This study was performed for the two canonical plasmonic metals, silver and gold, as well as for copper. By measuring the plasmonic resonances and comparing with simulations, we can obtain an accurate estimate of the nanogap sizes, finding that they are much smaller than one might expect – we think this effect is due to the interaction of van der Waals and contraction forces at the material interfaces. This will be particularly important for many of the future fiber-plasmonics devices we are designing.
In other news, paper “Excitation of Short-Range Surface-Plasmon Polaritons in a Gold Nanowire Enhanced Step-Index Fiber” has been accepted as an oral contribution for CLEO Europe, which will be held during the World of Photonics Congress 2017 in the International Congress Centre (ICM Munich, Germany). It will be presented June 27, 2017 at 8.45 in the Mode control session, ROOM 13b.
Just returned from a week in Australia, where I had the pleasure of attending the 16th (and final!) CUDOS workshop. This was an opportunity to participate in four days of discussion in a variety of forums such as keynote addresses, research presentations, poster displays and social events from several distinguished speakers – highlights included a keynote talk from Katherine Woodthorpe, and invited talks from Shanhui Fan, Kobus Kuipers, John Sipe and Alex Szameit, to mention a few. I presented a poster (see below) on our recent work , and met with my future colleagues at the University of Sydney Stefano Palomba, Martijn de Sterke and Guangyuan Li. The laser-tag skirmish event in the Australian bush during the record-setting heat-wave sun was as brutal an affair as one might imagine. The closing gala dinner delivered some emtional moments, as we all reflected on what made CUDOS so succesful, and the legacy it will leave: a combination of synergistic national and international collaborations, the ability to foster researchers both academically and into developing industrial partnerships and start-ups, student outreach, and contirbuting to overall excellence in photonics on a global scale, have created a truly unique research environment which will continue even after CUDOS ends, and which will serve as a model for research centers everywhere.
Our paper “Hybrid-Mode-Assisted Long-Distance Excitation of Short-Range Surface Plasmons in a Nanotip-Enhanced Step-Index Fiber” was published today. We propose a means of exciting short-range surface plasmon polaritons at the endface of a step-index fiber which contains a gold nanowire in its core. The radially polarized hybrid dielectric mode of the gold-filled section has low loss, with some field on the nanowire surface – so that after the light reaches the fiber endface, the energy propagates along the tip to nanoscale apex via the short-range plasmonic mode. We fabricated the structure and looked in detail at the properties of the scattered/transmitted light for different input polarizations. We found that the light scattered from the tip is most intense when the input is radially polarized, and that this light is polarized along the direction of the fiber axis, confirming the feasibility of this excitation scheme. This is a route to improving the capabilities of deeply-subwavelength near-field probes in a convenient fiber platform.