The year 2023 represents fifty years since Hasegawa and Tappert predicted that temporally-localized solitons could be generated in optical fibers. This opened up an entirely new field of nonlinear fiber optics, and soliton concepts are now central to many different areas of photonics including the design of ultrafast lasers, frequency comb generation, as well as interdisciplinary studies related to rogue waves. This tutorial will provide an overview of the field.

It will be explained how the propagation of picosecond and femtosecond pulses in optical fibers can be simulated, taking into account chromatic dispersion, various kinds of nonlinearities and wavelength-dependent saturable gain. (A special challenge is the latter, if both time and frequency domain need to be considered.) Coherence properties of frequency combs can be investigated with some additional statistical processing.

Various techniques can also be applied for pulse propagation in other kinds of media, such as waveguides in various doped insulators or silicon.

Philippe's tutorial explains the major evolution of optical soliton concepts in ultrafast lasers, largely driven by the fiber laser experimental platform and the dissipative soliton framework, which made scientists move beyond conventional laser stereotypes.

Over the past decade, the possibility of manipulating material and chemical properties by using hybrid light-matter states has stimulated considerable interest [1,2]. Such hybrid light-matter states can be generated by strongly coupling the material to the spatially confined electromagnetic field of an optical resonator. Most importantly, this occurs even in the dark because the coupling involves the zero-point electromagnetic fluctuations of the resonator, the vacuum field. After introducing the fundamental concepts, examples of modified properties of strongly coupled systems, such as magnetism, charge and energy transport, and chemical reactivity will be given to illustrate the broad potential of light-matter states.

Meta optical elements product by nanoimprint lithography

Design and application of individualy shaped freeforms arrays

Making an entire Optical Parametric Oscillators (OPO) smaller than a coin

Fermat is a recently founded spin-off by the Brussels Photonics Team (B-PHOT) of the Vrije Universeit Brussel (VUB), Belgium. Based on our proprietary and disruptive ‘First Time Right’ methodology, we develop outstanding imaging optics solutions that are exactly tailored to our customers’ very individual needs.

In this presentation, we will introduce the 'First Time Right' - based ecosystem. Our design methodology is derived from Fermat’s principle and allows calculating all optical surface coefficients that ensure minimal image blurring for each individual order of aberrations. We demonstrate the systematic, deterministic, scalable, and holistic character of our approach ranging from start lens generation to extreme catoptric and catadioptric freeform optical solutions.

Interfacing FEM analyses with optical design and simulations

Raman-on-a-chip technology

Deformable Phase Plates for Adaptive Optics: A Simple Solution for Correcting Complex Aberrations

LIDAR

To sustain cellular functions, a cell needs to transport a variety of cargos within the complex intracellular milieu. This task is mainly carried out by molecular motors that move along filament tracks. Despite the grand challenges to fully understand how cells exactly manage to execute all their intelligent functions, construction of artificial nanosystems by taking inspiration from the working principles that cellular components follow, is undoubtedly an intellectually efficient approach.

In this talk, we will show several types of bio-inspired optical nanosystems, which can perform rotation, twisting, or swinging motions enabled by dynamic DNA nanotechnology. Our approach outlines a general scheme to build dynamic plasmonic nanoarchitectures, in which multiple optical elements can be readily reconfigured or transported to designated locations over long distances, resulting in programmed structural changes with high fidelity. Such plasmonic structures can find useful applications in different fields, ranging from optical sensing to data storage. In particular, the possibility to translocate optical elements in multiple configurations can be used to explore new approaches to encode information at high density.

Ultrafast, intense, laser pulses are able to induce a wealth of non-linear effects in the atmosphere as they propagate, such as filamentation, plasma generation, non-linear photochemistry and shock waves. The successful use of these processes for guiding natural lightning strikes and for piercing clear channels in fog for free space optical communication (FSO) is presented.

We present the latest progress towards high resolution, long range Coherent Focal Plane Array sensors based on FMCW ranging with an emphasis on monostatic architectures.

Optical correlations are useful for many sensing and metrology applications including imaging, interferometry and LiDAR. Quantum illumination (QI) is a special example: it uses non-classical optical correlation (entanglement) to effectively filter uncorrelated noise from real LiDAR signals. Despite its impact QI only excels in the few photon regime. Therefore, when built using inherently low power quantum sources QI cannot compete with classical LiDAR systems with mW level probe light. In this talk we demonstrate quantum-inspired LiDAR which utilizes broadband phase correlations in nonlinear waveguides with effective second order nonlinearities, to effectively reduce in-band noise power by over 100dB with single-photon sensitivity. It is empowered by a receiver which utilizes sum-frequency in optical waveguides with record conversion efficiency.

Genetic targeting of neuronal cells with activity reporters (calcium or voltage indicators) has initiated the paradigmatic transition whereby photons have replaced electrons for reading large-scale brain activities at cellular resolution. In parallel, optogenetics has demonstrated that targeting neuronal cells with photosensitive microbial opsins, enables the transduction of photons into electrical currents of opposite polarities thus writing, through activation or inhibition, neuronal signals in a non-invasive way1. These progresses have in turn stimulated the development of sophisticated wave front shaping approaches, based on computer generated holography and temporal focusing, to enable in depth “all optical” brain circuits interrogation with high spatial and temporal resolution2: an essential methodology to link neuronal circuits activity to the control of memory, learning and perception in pathological and healthy brain. Here, we will review the working principles of all-optical methods and will show few breakthrough applications where they have been used for the investigation of visual circuits in mice models.

The past decade has witnessed a step-change in the scale, complexity, and scope of quantum information processing with photonics. Breakthroughs include photonic chips with dense co-integration of a large number of components, deterministic single photon sources with large purity, and high efficiency single photon detectors. Within this framework Boson Sampling is a computational problem that has been proposed as a candidate to obtain an unequivocal quantum computational advantage. There is strong evidence that such an experiment is hard to classically simulate, but it is naturally solved by dedicated photonic quantum hardware, comprising single photons, linear evolution, and photodetection. This prospect has stimulated much effort resulting in the experimental implementation of progressively larger devices. We will review recent advances in photonic boson sampling, describing both the technological improvements achieved and the future challenges. We will discuss recent proposals and implementations of variants of the original problem, theoretical issues occurring when imperfections are considered.

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DYNAMOS develops fast (1 ns) and widely tunable (>110 nm) lasers, energy-efficient (~ fJ/bit), broadband (100 GHz) electro-optic modulators, and high-speed (1 ns) broadcast-and-select packet switches as photonic integrated circuits (PICs). DYNAMOS meets the expected outcome objectives and call scope by proposing the development of low energy (few pJ/bit) PICs, which are integrated into modular and scalable subsystems, and subsequently utilized to demonstrate novel data centre networks with highly deterministic sub-microsecond latency to enable maximum congestion reduction, full bisection bandwidth (lower congestion) and guaranteed quality of service while reducing cost per Gbps.

The proposed network offers optical circuit switched reconfiguration and guaranteed (contentionless) full-bisection bandwidth, allowing any computational node to communicate to any other node at full-capacity. DYNAMOS builds on recent developments in III-V optoelectronics, thick silicon-on-insulator waveguide technology, and silicon organic hybrid (SOH) modulators. It co-develops the entire ecosystem of transceivers, switches and networks to boost overall performance and to reducing the total cost of data exchange, instead of focusing on the improvement of individual optical links or interfaces. The objectives of DYNAMOS perfectly match the major photonics research & innovations challenges defined in the Photonics21 Multiannual Strategic Roadmap 2021-2027.

There is an absence of lasers with the necessary wavelengths and characteristics to access the possibilities for deeper high-resolution biological tissue imaging in the third bio-window between 1650 nm and 1870 nm. Motivated by recent breakthrough results in multi-photon imaging at twice the depths currently achievable, we will meet the urgent need for new sources to address the outstanding research questions in this spectral region. Results will guide and enable instrument development in this appealing and relatively unexplored biophotonics imaging wavelength range.

The AMPLITUDE consortium proposes a new concept of label-free, multi-modal microscopy and endoscopic imaging operating in this new wavelength region with multiple imaging and spectroscopic technologies, including NIR confocal reflectance microscopy, multi-photon microscopy and spontaneous Raman spectroscopy.

By progressing ultrafast fibre laser developments at 1700 nm, we will deliver new imaging capabilities in an appropriate form factor and at cost suitable for widespread adoption. This will be further enhanced by providing additional output at 850 nm using second harmonic generation from one integrated laser device.

This will enable a pioneering new compact and efficient multi-modal capability combining confocal and non-linear imaging techniques, overcoming performance limitations in medical and biological imaging applications, including improved pathohistological staging of tumours and in-vivo endoscopic assessment of depth of lesion invasiveness. Deeper multi-photon microscopy with autofluorescence imaging of cellular metabolic conditions, whose aspects are tightly related to cellular functioning and to cancer, implemented in tandem with Raman spectroscopy will provide exhaustive characterisation of the examined tissue at morphological, metabolic and molecular levels, allowing in-vivo optical biopsy for bladder cancer diagnosis, grading and staging.

The continuous growth of the global population has been remarking the need of early detection systems to prevent the spread of epidemics as well as to improve the standards of living. The emerging demand of sensing technologies has prompted researchers and industrial companies to develop devices able to monitor medical, food, water, and environmental safety/quality indicators in an efficient, simple, and reliable way. While high sensitivity and selectivity must be guaranteed, compactness, user-friendliness and low-cost are key characteristics to enable the use of the sensing technology for point-of-care diagnostics without the need for trained personnel [1].

Among state-of-the-art methodologies for pollutants detection, optical sensing has emerged as one of the most simple, versatile, and powerful approaches for analytical purposes. However, a major obstacle towards the development of a portable system has been the use of bulky optical components (e.g. lasers and optical fibers), which are necessary to ensure a good sensing capability. In particular, huge interest has been attracted by functionalized metallic surfaces based on surface plasmon resonance (SPR), as extremely sensitive, label-free, quantitative systems for real-time detection of single or multiple analytes. However, the need of a fine and precise control of the angle of the incident light ended up in the use of not-portable optical components in the final sensor [2].

In this scenario, organic optoelectronic components might enable the definition of new miniaturized detection schemes to boost the advent of compact optical sensors for on-site analysis, given their inherent capability of smart monolithic integration in nm-thick multi-stack devices on almost any surface.

Here, we report an unprecedented ultra-compact system endowed with optical and plasmonic sensing capabilities through the smart integration of (i) organic light-sources such as organic light-emitting diodes (OLEDs) or transistors (OLETs), (ii) an organic light-detector such as organic photodiode (OPD) and (iii) a sensing nanostructured surface such a nanoplasmonic grating (NPG) [3]. The components and the layout of integration were suitably designed to make the elements work cooperatively in a reflection-mode configuration. In particular, the OPD was vertically stacked onto the source electrode of the OLET thus providing electrical switching, light-emission and light-sensing capability in a single organic multilayer architecture. When coupled to the NPG, a multifunctional system with SPR-sensing ability was obtained at a remarkably high level of miniaturizationat a sensor size as low as 0.1 cm3, arising from the direct fabrication of the NPG onto the encapsulating cap of the light-emitting/-sensing platform [4].

Once finalized into a working prototype and operated with standard solutions, the sensor is calibrated by providing quantitative and linear response that reaches a limit of detection of 10−4 refractive index units. Analyte-specific and rapid (15 min long) immunoassay-based detection is demonstrated for targets relevant for the milk chain. By using a custom algorithm based on principal-component analysis, a linear dose–response curve is constructed which correlates with a limit of detection as low as 3.7 µg mL−1 for lactoferrin, thus assessing that the miniaturized optical biosensor is well-aligned with the chosen reference benchtop SPR method.

[1] R. Dragone, …, S. Toffanin Frontiers in Public Health, 2017, 5, 1.

[2] M. Prosa, ..., S. Toffanin Nanomaterials 2020, 10, 480.

[3] M. Bolognesi, ..., S. Toffanin Adv. Mater. 2023 2208719

[4] M. Prosa, ..., S. Toffanin, Adv. Funct. Mater. 2021, 31, 2104927.

A high power 1.8 kW laser providing from picosecond down to femtoseconds pulses at repetition rates up to 1GHz with excellent beam quality will be developed and brought to the market at highly competitive costs enabling widespread industrial uptake. By harnessing the unique characteristics of patent protected tapered double-clad fiber amplifiers power-scaled multichannel laser, unparalleled high-power beam qualities, and pulse energies 2.5-250µJ will be achieved. Using the state-of-the-art highly stable laser diodes as seed lasers allowing parameter flexibility by ultrafast electrical control of pulse duration and repetition rate will a broad range of high-power laser processing application requirements to be met. An extremely stable advanced all-fiber based configuration allow development of a compact ultrashort pulse laser system. A newly-designed delivery fiber utilising cutting-edge technology of high purity glass material fabrication will be used to capable of handling the very high power ultra-short pulses, preserving beam quality over several meters distance. Pioneering technology based on 3D nano-imprint lithography will be exploited to produce coherent beam combining optics and fiber-facet-integrated micro-lenses for advanced beam shaping elements to elongate voxels. Together these will provide laser pulse delivery via patented polygon scanner technology capable of handling high-power pulses at speeds of up to 1.5 km/s. These will enable demonstration in automotive and renewable energy sectors of ultrafast 3D ablation, low-thermal welding of dissimilar metals and faster cost-effective cutting of ultra-hard materials. Exploitation in the form of high-power laser processing systems will immediately follow, benefitting from the unmatched performance data and detailed cost benefit and investment case analysis performed.

Dual-comb molecular and pump-probe spectroscopy with equivalent time sampling are currently limited by the cost, complexity, and size of conventional optical comb systems, based on two modelocked lasers and corresponding feedback loops. The single-cavity dual-comb diode-pumped solid-state and semiconductor lasers, however, substantially reduce the complexity of existing systems to a single compact free-running laser. In comparison to other competing new approaches such as quantum cascade lasers or micro resonator combs, these dual-comb lasers provide substantially more power per comb line with low linewidth and noise, and are ideally suited for a 40 MHz to 5 GHz comb spacing. The optimal operating regime lies within this range for many different applications including spectroscopy and thin-film inspection, allowing for fast, accurate, and sensitive measurements.