Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Processing of materials by ultrashort laser pulses has evolved significantly over the last decade and is starting to reveal its scientific, technological and industrial potential. In ultrafast laser manufacturing, optical energy of tightly focused femtosecond or picosecond laser pulses can be delivered to precisely defined positions in the bulk of materials via two-/multi-photon excitation on a timescale much faster than thermal energy exchange between photoexcited electrons and lattice ions. Control of photo-ionization and thermal processes with the highest precision, inducing local photomodification in sub-100-nm-sized regions has been achieved. State-of-the-art ultrashort laser processing techniques exploit high 0.1–1 μm spatial resolution and almost unrestricted three-dimensional structuring capability. Adjustable pulse duration, spatiotemporal chirp, phase front tilt and polarization allow control of photomodification via uniquely wide parameter space. Mature opto-electrical/mechanical technologies have enabled laser processing speeds approaching meters-per-second, leading to a fast lab-to-fab transfer. The key aspects and latest achievements are reviewed with an emphasis on the fundamental relation between spatial resolution and total fabrication throughput. Emerging biomedical applications implementing micrometer feature precision over centimeter-scale scaffolds and photonic wire bonding in telecommunications are highlighted.

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Ultrafast laser processing of materials: from science to industry

The boson-sampling problem was demonstrated by studying three-photon interference in a five-mode integrated interferometer containing three-dimensional S-bent waveguides. Three single photons were input into the interferometer and the probability ratios of all events were measured. The results agree with quantum mechanical predictions for three-photon interference.

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Integrated multimode interferometers with arbitrary designs for photonic boson sampling

Studies of the nonlinear optical phenomena that describe the light-matter interactions in 2D crystalline materials have promoted a diverse range of photonic applications. MXene, as a recently developed new 2D material, has attracted considerable attention because of its graphene-like but highly tunable and tailorable electronic/optical properties. In this study, we systematically characterize the nonlinear optical response of MXene Ti3C2Tx nanosheets over the spectral range of 800 nm to 1800 nm. A large effective nonlinear absorption coefficient (βeff∼-10−21 m2/V2) due to saturable absorption is observed for all of the testing wavelengths. The contribution of saturable absorption is two orders of magnitude higher than other lossy nonlinear absorption processes, and the amplitude of βeff strongly depends on the light bleaching level. A negative nonlinear refractive index (n2∼-10−20 m2/W) with value comparable to that of the intensively studied graphene was demonstrated for the first time. These results demonstrate the efficient broadband light signal manipulating capabilities of Ti3C2Tx, which is only one member of the large MXene family. The capability of an efficient broadband optical switch is strongly confirmed using Ti3C2Tx as saturable absorbers for mode-locking operation at 1066 nm and 1555 nm, respectively. A highly stable femtosecond laser with pulse duration as short as 159 fs in the telecommunication window is readily obtained. Considering the diversity of the MXene family, this study may open a new avenue to advanced photonic devices.

Broadband Nonlinear Photonics in Few-Layer MXene Ti3C2Tx (T = F, O, or OH)

Space-division multiplexing (SDM) uses multiplicity of space channels to increase capacity for optical communication. It is applicable for optical communication in both free space and guided waves. This paper focuses on SDM for fiber-optic communication using few-mode fibers or multimode fibers, in particular on the critical challenge of mode crosstalk. Multiple-input–multiple-output (MIMO) equalization methods developed for wireless communication can be applied as an electronic method to equalize mode crosstalk. Optical approaches, including differential modal group delay management, strong mode coupling, and multicore fibers, are necessary to bring the computational complexity for MIMO mode crosstalk equalization to practical levels. Progress in passive devices, such as (de)multiplexers, and active devices, such as amplifiers and switches, which are considered straightforward challenges in comparison with mode crosstalk, are reviewed. Finally, we present the prospects for SDM in optical transmission and networking.

Space-division multiplexing: the next frontier in optical communication

Thermally stable fiber Bragg gratings for the mid-IR are demonstrated. While the grating strength and design wavelength typically change during post-annealing, we report here on grating structures which are resilient to temperatures of up to 200°C

Femtosecond laser-inscribed mid-infrared fiber Bragg gratings with enhanced thermal stability

We developed a randomly-coupled 19-core fiber with standard 125-μm cladding diameter with spatial mode dispersion of $10.8{\text{ps}}/\sqrt {{\text{km}}}$, enabling a data rate of 1.7 Pb/s, the highest reported amongst optical fibers with standard cladding diameter.

Randomly Coupled 19-Core Multi-Core Fiber with Standard Cladding Diameter

Three dimensional lightwave circuits, fabricated using femtosecond laser direct-write techniques, are enabling new applications in quantum optics, astronomy and telecommunications. We review those and highlight our recent work on 3D compact, passive mode selective couplers.

Laser Written 3D Lightwave Circuits and Applications

Laservorrichtung zur ablation von biologischem gewebe

The femtosecond laser direct write technique enables the fabrication of integrated three dimensional miniaturised optical components in various transparent dielectric media by translating those samples with a computer controlled stage with respect to a tightly focused laser beam. Nonlinear absorption processes can lead to a pathway of local permanent index change inside the material. In this paper we review our work in glasses doped with active ions. Integrated waveguide amplifiers working in the wavelength range between 1–3 micron have been realised by inscribing low-loss optical waveguides in phosphate, borosilicate or fluoride glasses doped with rare-earth ions like erbium, ytterbium, holmium or thulium. By incorporating wavelength-selective feedback elements like fibre- or waveguide Bragg gratings or distributed feedback structures, integrated chip lasers have been fabricated.

Simon Gross

Papers

Femtosecond laser-inscribed mid-infrared fiber Bragg gratings with enhanced thermal stability

Randomly Coupled 19-Core Multi-Core Fiber with Standard Cladding Diameter

Laser Written 3D Lightwave Circuits and Applications

Laservorrichtung zur ablation von biologischem gewebe

Integrated waveguide lasers