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Optical waveguides represent the key element of integrated planar photonic circuitry having revolutionized many fields of photonics ranging from telecommunications, medicine, environmental science and light generation. However, the use of solid cores imposes limitations on applications demanding strong light-matter interaction within low permittivity media such as gases or liquids, which has gas triggered substantial interest towards hollow core waveguides. Here, we introduce the concept of an on-chip hollow core light cage that consists of free standing arrays of cylindrical dielectric strands around a central hollow core implemented using 3D nanoprinting. The cage operates by an anti-resonant guidance effect and exhibits extraordinary properties such as (1) diffractionless propagation in "quasi-air" over more than one centimetre distance within the ultraviolet, visible and near-infrared spectral domains, (2) unique side-wise direct access to the hollow core via open spaces between the strands speeding up gas diffusion times by at least a factor of 10 4 , and (3) an extraordinary high fraction of modal fields in the hollow section (> 99.9%). With these properties, the light cage can overcome the limitations of current planar hollow core waveguide technology, allowing unprecedented future on-chip applications within quantum technology, ultrafast spectroscopy, bioanalytics, acousto-optics, optofluidics and nonlinear optics. MotivationOne of the key objectives in current photonics research is to reduce the geometric footprint of bulky optical components by replacing them with their compact on-chip integrated counterparts in a costefficient way. Remarkable progress has been made in the development of planar waveguides, which constitute the principle element of integrated photonic devices, with applications in quantum technology [1], nonlinear physics [2] [3] and biophotonics [4]. However, most waveguides rely on solid cores, limiting the design flexibility of photonic sensors that require intense light-analyte interaction in medium with a lower dielectric permittivity as gases and liquids. The sensitivity of waveguides to detect refractive index (RI) changes of analytes is correlated to the fraction of electromagnetic power in the sensing medium and thus efforts are concentrated on finding guidance schemes which allow an enhanced concentration of light in the low index medium.One widely used sensing approach relies on evanescent waves. Integrated waveguides with exposed cores can provide access to the evanescent fields and found applications in areas such as spectroscopy and biosensing [5] [6] but can demand excessively long waveguide lengths to

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Following the reanalysis of individual experimental runs of some widely cited studies (Jain et al., 2018, https://doi.org/10.1002/2017JB014847), we revisit the global data analysis of Korenaga and Karato (2008, https://doi.org/10.1029/2007JB005100) with a significantly improved version of their Markov chain Monte Carlo inversion. Their algorithm, previously corrected by Mullet et al. (2015) to minimize potential parameter bias, is further modified here to estimate more efficiently interrun biases in global data sets. Using the refined Markov chain Monte Carlo inversion technique, we simultaneously analyze experimental data on the deformation of olivine aggregates compiled from different studies. Realistic composite rheological models, including both diffusion and dislocation creep, are adopted, and the role of dislocation-accommodated grain boundary sliding is also investigated. Furthermore, the influence of interrun biases on inversion results is studied using experimental and synthetic data. Our analysis shows that existing data can tightly constrain the grain-size exponent for diffusion creep at ∼2, which is different from the value commonly assumed (p = 3). Different data sets and model assumptions, however, yield nonoverlapping estimates on other flow-law parameters, and the flow-law parameters for grain boundary sliding are poorly resolved in most cases. We thus provide a few plausible candidate flow-law models for olivine rheology to facilitate future geodynamic modeling. The availability of more data that explore a wider range of experimental conditions, especially higher pressures, is essential to improve our understanding of upper mantle rheology.

This paper proposes a single-phase doublestage scheme, for grid interfaced load compensating solar photovoltaic (PV) generating system. The scheme serves twofold objectives of alleviating power quality issues such as power factor correction and harmonics mitigation, while simultaneously extracting the maximum power generated by the PV unit. A simple notch-filtering control algorithm is designed to facilitate extraction of the real component of load current, exempting the services of a phase locked loop (PLL). The absence of a PLL reduces the system dependence on the PI controller tuning, which in turn improves the dynamic response and makes the system quite robust. The proposed solar PV generation system retains its ability of mitigating harmonics on cloudy days and also provides opportunity for night time utilization of available resources. The system has been analyzed under both linear and nonlinear varying loads using and an experimental verification of the results is carried out on a developed prototype of the system.