The AiPT research seminars bring together international experts and AiPT staff, fostering an environment of knowledge sharing and discovery across a range of diverse topics. The AiPT research seminars continue to promote scientific dialogue and engagement among the global research community, ensuring that AiPT remains at the forefront of innovation and discovery in the fields of photonics and telecommunications.
Assis Prof Abhijit Mitra, Indraprastha Institute of Information Technology Delhi (IIIT-Delhi)
Talk title: “Research Activity of IIIT Delhi and its impact on Advanced Optical Communication Testbed in India”.
Date, Time, Venue: 28 September 2023, 11 am, NW708 & in TEAMS
Abhijit Mitra received his Ph.D. from the Indian Institute of Technology Delhi (2017) under the funding of the British Telecom Fellowship. His experience has been in modeling and network planning for metro and core optical networks. He has been a reviewer in reputed journals like the Journal of Optical Communication and Networking (JOCN), and the Journal of Lightwave Technology (JLT). He has published in major venues like Proceedings of the IEEE, JOCN, JLT, Optical Fiber Communications (OFC) Conference, and the European Conference on Optical Communications (ECOC) with due industry-academic collaborations. Further, he has led funded projects by DST, MIETY, and DRDO in the capacity of PI/Co-PI and functioning as a collaborator in a project funded by the National Science Foundation (NSF), USA. He has been awarded the DST Inspire Faculty Fellowship (2017-2022) by DST, the British Council (Alumni Awards): Professional Achievement Awards (2019) by the British Council, the prestigious Fulbright Post Doctoral Research Fellowship by the United States India Education Foundation (USIEF) and Sparkle-Marie Skłodowska-Curie Actions (MSCA) Cofund Fellowship (2022, not availed). Overall he has 10 years of research experience in Transport Optical Networks.He is presently serving as a member of the Advanced Optical Communication Testbed activity funding by the Department of Technology, Govt. of India where he is leading work on C+L Band Optical Networks.
Dr Daniel Hill, AiPT, Aston University
Talk title: “MONPLAS and beyond, challenges in the development of analytical technologies for micro and nanoplastics”.
Talk abstract: MONPLAS or “The training of Early Stage Researchers (ESRs) for the development of technologies to MONitor concentrations of micro and nano PLAStics in water for their presence, uptake, and threat to animal and human life” is an Horizon 2020 Initial Training Network project that is developing both future research leaders and state of art solutions to analytical technology and methodology challenges for the characterisation and enumeration of micro and nanoplastics. In this talk the project will be introduced, after which focus will be placed on the optical and photonic technologies developed and applied by the 14 ESRs, before remaining challenges, both in technology and harmonisation/standardisation of procedures, are highlighted and opportunities flagged for ongoing and future projects and collaborations.
Date, Time, Venue: 2 October 2023, 11:00 am, NW708 & in TEAMS
Dr Aleksei Zheltikov, Institute for Quantum Science and Engineering, Department of Physics and Astronomy, Texas A&M University
Talk title: “Ultrafast laser – plasma nonlinear optics: cross-range supercontinua, Cherenkov radiation, and rogue waves”.
Talk abstract: Combined optical nonlinearity of bound and free electrons in a fast-ionizing medium driven by ultrashort, high-peak-power laser pulses gives rise to a vast variety of ultrafast nonlinear-optical scenarios, producing bright and remarkably broadband radiation whose spectrum spans over multiple octaves and across different frequency ranges, from the x-ray to the microwave frequency band. Electric-current transients driven by high-peak-power mid-infrared laser pulses are shown to provide a source of broadband, wide-angle microwave–terahertz radiation, whose spectral, spatial, and polarization properties can be adequately understood in terms of Cherenkov radiation by an ultrafast laser-driven ionization front. When viewed from a perspective of rare-event statistics, the key nonlinear processes underlying this ultrafast laser – plasma nonlinear wave dynamics are recognized as rogue-wave effects.
Date, Time, Venue: 10 October 2023, 11:00 am, NW708 & in TEAMS
Aleksei Zheltikov received his PhD, as well as his Doctor of Science degree from M.V. Lomonosov Moscow State University in 1990 and 1999, respectively. He became a full professor at M.V. Lomonosov Moscow State University in 2000. Over a period of 1998 to 2022, he founded and supervised laboratories for ultrafast photonics and neurophotonics at M.V. Lomonosov Moscow State University, advanced photonics lab at the International Center for Quantum Technologies, and a lab for waveguide systems for quantum technologies at the Kazan Technical University. Since 2010, he has been a professor at Texas A&M University. His research is focused on ultrafast nonlinear optics, biophotonics, and quantum technologies.
Past Seminars Archive (2023)
Dr Richard Taylor
Talk title: “Commercialising University Research – Photonic Crystal Surface Emitting Lasers”.
Talk abstract:Semiconductor lasers are ubiquitous and have had wide reaching impacts on every aspect of modern life, including communications, to manufacturing, health monitoring, and many more. Over the last 60+ years there has been significant development in semiconductor lasers. Traditionally there are two basic semiconductor laser types: edge emitting lasers (EELs) and vertical cavity surface emitting lasers (VCSELs). Typically, VCSELs are low cost and can transmit at a high data rate, but these devices have a limited wavelength range and emit relatively low optical power, limiting their applications. EELs on the other hand can operate over a wide wavelength range, but manufacturing costs may be prohibitive for some applications. Recently a novel laser structure has been developed that can overcome the inherent compromises of these laser classes. The photonic crystal surface emitting laser (PCSEL) was the subject of Richards PhD and subsequent work. In this talk he will discuss the advantages of PCSELs over other laser devices, discuss his work on developing all-semiconductor PCSELS. Then he will discuss his journey from academic to company founder, and entrepreneur. He will discuss the challenges and opportunities faced in commercialising university research.
Date, Time, Venue: 11 September 2023
Dr Sandra de Vega, Menlo Systems GmbH
Talk title: “Frequency Combs for Quantum 2.0 Applications”.
Talk abstract: Within two decades, the optical frequency comb has revolutionised numerous fields in physics: precision spectroscopy, time and length-metrology, molecular fingerprinting, and ultra-low phase noise microwaves, to mention just a few applications. Being the only device with the ability to directly link the optical with the radio frequency domain, the frequency comb has become an irreplaceable tool, and not only for quantum optics laboratories.
In this talk, we will discuss about Menlo Systems’ ultra-low noise (ULN) frequency comb technology that ensures transferring the spectral purity of a superior optical reference to all CW lasers locked to the comb. This feature is exploited in clock comparisons and quantum experiments, where a long coherence time of the laser sources is mandatory.
Date, Time, Venue: 6 June 2023, 11:00 am, NW708 & in TEAMS
After my Physics studies, I specialised in Photonics through my PhD at ICFO, the Institute of Photonic Sciences, near Barcelona.
Since 2020, I am a Sales Engineer at Menlo Systems helping researchers around the world to design and procure those laser systems that enable their experiments.
Prof Robert Thomson, Heriot Watt University
Talk title: “Photonic lanterns and their applications”.
Talk abstract: Photonic lanterns are guided wave components that facilitate the efficient transfer of light between multimode and single mode guided wave systems. In this talk, I will discuss how photonic lanterns work, how they can be fabricated and some of the emerging applications for these powerful devices.
Date, Time, Venue: 24th May from 12:15 to 1:15 pm, NW708 & MS Teams
Robert R. Thomson obtained the B.Sc in Physics from Heriot Watt University in 2000, the M.Sc in Optoelectronics and Laser Devices from the University of St Andrews in 2001, and the Ph.D in Physics from Heriot Watt University in 2006. From 2010-15 he was an STFC Advanced Fellow, developing photonic technologies for applications in astronomy. He is currently Full Professor of Photonics at the Institute of Photonics and Quantum Sciences (IPaQS) at Heriot Watt University in Edinburgh, Scotland, where he leads the photonic instrumentation group (phi.eps.hw.ac.uk). He has published over 100 articles in leading journals such as Adv. Opt. Photon., Phys. Rev. Lett., and Nat. Commun. and has received grants valued at >£34M (£10M as PI). His research interests range from fundamental optics to highly applied photonics in areas such as ultrafast laser micro-fabrication and biomedical photonics (see u-care.ac.uk). He co-founded Optoscribe Ltd in 2010, which was acquired by Intel in 2022.
From wave turbulence to integrable turbulence and soliton gases
Prof Stéphane Randoux, Université de Lille
The nonlinear propagation of random dispersive waves has been an active research topic in nonlinear physics since the 1960s. Historically, a very important part of the work on this subject has been focused on weak wave turbulence. Wave turbulence theory (WT) deals with the non-equilibrium statistics of incoherent and weakly nonlinear dispersive waves in non-integrable systems. On the other hand, many physical systems are described at leading order by partial differential equations (such as the nonlinear 1D Schrodinger equation) that are integrable in the sense that they can be solved using the inverse scattering transform (IST) method. Nowadays, the theoretical description of nonlinear random wave fields in integrable systems is addressed in the framework of so-called “integrable turbulence”, a research area introduced by Zakharov in 2009. In this talk, I will review experimental and numerical developments on the subject of integrable turbulence with a focus on the topic of soliton gas.
TRENDS IN SCIENTIFIC PUBLISHING
Oliver Graydon, Chief Editor of Nature Photonics
An overview of the latest innovations, trends and future direction of journal publishing with a focus on the relevance to the optics and photonics sectors. Topics to be covered include the growth of journals in the optics sector, the rise of open access publishing, the evolution of peer review, the emergence of open data and code and advice on writing high quality scientific papers.
Computation with degenerate optical parametric oscillator networks
Prof Hiroki Takesue, NTT Basic Research Laboratories, NTT Corporation
As the progress of the digital computers shows the signs of saturation, exploration of new computing schemes based on the dynamics of various physical systems is becoming an important research field. Among many schemes, a coherent Ising machine (CIM), which is an Ising model simulator based on a network of optical parametric oscillators (DOPOs), is drawing attention as a way to solve combinatorial optimization problems efficiently. A CIM employs a km-scale fiber cavity including a phase sensitive amplifier (PSA) based on degenerate optical parametric amplification in a periodically-poled lithium niobate (PPLN) waveguide, where thousands of time-multiplexed DOPO pulses are generated. In the paper “A coherent Ising machine for 2000-node optimization problems”, we reported a CIM that enabled flexible (from very sparse to all-to-all) couplings among 2,000 DOPO pulses using measurement-feedback technique. In this talk, I will describe the basic concept of the CIM, and report our recent progress on the CIM research, including a comparison of computational performance with a quantum annealing machine and a realization of 100,000 spin CIM. I will also describe an implementation of a spiking neuron using a pair of DOPO pulses, which may be useful for future research on brain-inspired computations.
Nd doped fiber for E-band amplification
Dr Leily Kiani, Lawrence Livermore National Laboratory (LLNL), US
There are a few fiber design approaches for suppressing competitive gain in doped core fibers by spectrally filtering light the core. Fibers having concentric index profiles like the W-profile, sometimes referred to as depressed-well or trench profiles, have been developed for inducing loss of the fundamental guided mode at long wavelengths. Here the confinement losses grow as the mode field expands for long wavelengths generating an extended short-pass filter. An alternative filtering scheme based on high dispersion elements located adjacent to the core can provide spectrally selective filtering. Dr. Leily Kiani will review the design, fabrication, and test results of a spectrally selective filtering Nd-doped silica fiber for E-band amplification. The waveguide design includes elements that induce core loss at selective wavelengths in competitive bands, enabling efficient amplification of 1400 nm.
Fiber lasers activity at Tampere University
Dr. Regina Gumenyuk, Tampere University
Fiber lasers have already gained an excellent reputation due to a number of features such as good beam quality, high plug-in efficiency, stability and compactness. However, there is a constant demand for advanced performance. Our research focuses on investigating novel fiber lasers for emerging applications such as green material processing, high-precision bioimaging, and sensitive spectroscopic techniques or new energy sources. Our primary interests are new wavelength range, nonlinear intracavity soliton dynamics, the investigation of novel laser regimes and high-power lasers based on an active tapered amplifier technology and coherent beam combining. Recently, we have launched a new research direction – direct generation of the structured light in an active helical fiber.
Long wavelength InAs-based quantum cascade lasers
Prof Alexei Baranov, Research Director, IES – Institut d’Electronique et des Systèmes Université de Montpellier
Quantum cascade lasers (QCLs) have now become a versatile laser technology covering an extremely broad spectral range from mid-infrared to THz frequencies. These devices can be referred to as GaAs-, InP- and InAs-based QCLs depending on the substrate used for their growth. IES is a recognized leader in the development of InAs-based QCLs. The initial interest to this material system was due to the giant conduction band offset of 2.1 eV between InAs and AlSb, which made it possible to obtain high energies of intersubband transitions and to demonstrate the shortest QCL emission wavelength of 2.6 µm.
The small electron effective mass in InAs is another property of antimonides attractive for use in QCLs, which can provide a higher intersubband gain compared with other materials. This advantage can be fully exploited in long wavelength devices emitting beyond 10 µm, where the active quantum levels of the laser transition are close to the bottom of the conduction band and the electron effective mass is not increased by the nonparabolicity effects. Even the very early long wavelength InAs-based QCLs outperformed InP- and GaAs-based counterparts operating in the 16-24 µm range. With these QCLs we demonstrated the first semiconductor lasers operating at room temperature up to a wavelength of 21 µm. Using a dielectric waveguide instead of the usually employed in long wavelength QCLs double metal surface plasmon waveguide we have succeeded to further improve the device performance. The waveguide improvement was then completed with a design and doping optimisation, which resulted in the achievement of room temperature continuous wave (cw) operation at wavelengths up to 17.8 µm, thus establishing a new record for any semiconductor laser. We have obtained cw operation up to 320K for QCLs emitting near 11 µm and up to 240K at 21 µm. Pulsed operation at 25.5 µm at temperatures up to 240K has also been demonstrated. The state-of-the art of the long wavelength mid-infrared QCLs emitting below the reststrahlen band will be reviewed. Issues related to the multiphonon absorption in the considered spectral region will also be discussed.
Tissue spectroscopy for the development of noninvasive cancer detection
Prof Luís M. Oliveira, Porto University
Tissue spectroscopy is one of the Biophotonics methods used to acquire information about the internal composition of biological tissues and fluids. Although this method provides valuable information to develop clinical procedures based on the use of light, it presents certain disadvantages, such as the necessity of tissue excision to perform measurements. Using a fast calculation method based on the photon diffusion theory it was possible to calculate the spectral optical properties of various animal and human tissues from the ultraviolet to the infrared. The results obtained from the spectral absorption coefficient of different tissues provided physiological and diagnostic information associated with cancer development. In the case of rabbit pancreas, a similar accumulation of melanin and lipofuscin demonstrated that these pigments accumulate in tissues as a result of the aging process. The observed higher content of melanin relative to the lipofuscin content in the rabbit brain was associated with the occurrence of neurodegenerative processes that occur in the brain. Considering both healthy and cancer tissues from the human colorectal mucosa and kidney, it was possible to detect the formation of melanolipofuscin granules as a biomarker of cancer development. Other cancer biomarkers, such as higher blood content and higher mobile water content were also identified from the analysis of the spectral optical properties and application of optical clearing treatments. By using diffuse reflectance spectral measurements in the development of machine learning algorithms it was possible to reconstruct the absorption spectra of human healthy and diseased tissues with good accuracy, which leaded to the recovery of similar results about the blood and pigment contents in each case.
Fibre optic sensing to inform underground construction operations
Dr Brian Sheil, Laing O’Rourke Associate Professor in Construction Engineering, University of Cambridge
Uncertainty surrounding how structures interact with soil remains a key barrier to project optimisation on the basis of cost, time and emissions. However, robust and reliable sensors to measure soil pressures during underground construction do not exist. This presentation describes the development of a new more sophisticated generation of force and pressure sensors by fusing fibre optic sensing with machine learning. The deployment of prototypes on a recent UK construction project and the corresponding impact is also discussed.
Universal light encoders: artificial intelligence hardware for machine vision, sensing, and universal metrology
Prof Andrea Fratalocchi, KAUST University
In this invited talk, I will summarize recent research results in the field of universal light encoders. These components represent a particular class of metasurfaces implementing optical hardware feedforward neural networks that can universally approximate any user-defined input-output function. In the first series of applications, I will discuss the exploitation of this technology to implement ultra-flat (60 nm thick) optical components for vectorial light control with near-unity experimental efficiencies in the visible. In the second part, I will discuss a new area of research that focuses on the implementation in the hardware of software machine learning concepts for various applications in machine vision. I will summarize the fundamentals of HyplexTM, a new hyperspectral technology platform that allows the acquisition and processing of high-resolution videos in real-time for a broad spectrum of applications, including remote sensing, medical diagnosis, precision agriculture, and security.