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

Integrated photonics is a promising technology platform for use in space based environments. In this paper we explore the effects of space-like conditions, including temperature, pressure, and exposure to x-rays and gamma rays, on waveguides fabricated in glass by the femtosecond laser direct write technique.

Prospects for integrated photonics in space applications

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Temperature distribution in a gas-solid fixed bed probed by rapid magnetic resonance imaging

Low-loss photonic nulling interferometer in the mid-infrared for astronomical applications

In recent years, the femtosecond laser direct write technique has evolved into a standard technique for the inscription of optical waveguides in glasses. However, due to very slow process speeds and limited 3D-capabilities, this method was restricted to the fabrication of relatively simple structures so far. In this paper we demonstrate how MHz repetition rate chirped-pulse oscillators can be utilised to overcome those limitations, enabling the realisation of complex direct-written microstructured waveguides. We present our results in fabricating ARROW (anti-resonant reflecting optical waveguide) structures in bulk glasses as well as depressed-cladding waveguides in novel fluoride glasses doped with rare-earth ions like thulium and holmium.

Femtosecond laser direct-written microstructured waveguides in passive as well as in novel active glasses

Symmetric waveguides that are mode-matched to standard single-mode fiber have been fabricated in SF57 with fs laser pulses at peak powers below the threshold for critical self-focusing and high repetition rates, utilizing cumulative heating effects.

Simon Gross

Papers

Prospects for integrated photonics in space applications

Temperature distribution in a gas-solid fixed bed probed by rapid magnetic resonance imaging

Low-loss photonic nulling interferometer in the mid-infrared for astronomical applications

Femtosecond laser direct-written microstructured waveguides in passive as well as in novel active glasses

Fabrication of Type I Waveguides in Highly Nonlinear SiO2–PbO Glasses Using fs Laser Pulses at MHz Repetition Rates