A fundamental quantity in multiple scattering is the transport mean free path the inverse of which describes the scattering strength of a sample. In this paper, we emphasize the importance of an appropriate description of the effective refractive index n eff in multiple light scattering to accurately describe the light transport in dense photonic glasses. Using n eff as calculated by the energy-density coherent-potential approximation we are able to predict the transport mean free path of monodisperse photonic glasses. This model without any fit parameter is in qualitative agreement with numerical simulations and in fair quantitative agreement with spectrally resolved coherent backscattering measurements on new specially synthesized polystyrene photonic glasses. These materials exhibit resonant light scattering perturbed by strong near-field coupling, all captured within the model. Our model might be used to maximize the scattering strength of high index photonic glasses, which are a key in the search for Anderson localization of light in three dimensions. DOI: 10.1103/PhysRevA.96.043871 Transport phenomena are omnipresent in nature, governing many processes in chemistry, biology, physics, and engineering. Systems as diverse as electrons [1] and ultrasound [2] in condensed matter, mechanical waves in the earth [3], cold atoms in an optical trap [4], and light in disordered photonic materials [5] share the same physical principle [6,7]. Optical experiments are especially appealing because of the absence of photon-photon interaction (unlike in electronic systems) and the existence of relatively high index scattering media such as photonic crystals and glasses. Moreover, optical transport experiments have reached an unprecedented accuracy thanks to the great technological development of sources (e.g., lasers), detectors (e.g., CCDs), and time resolution. All these progresses allow the realization of table-top experiments which highlight the richness of transport phenomena.Wave transport in a diluted disordered suspension of scatterers can be described by the sole far-field properties of the single scatterers. On increasing concentration, however, interference effects due to scatterer-scatterer position correlation need to be taken into account [8]. In this description, the scattering cross section is still the single scatterer one, which, in general, is calculated in the far field. In optics, this approach is expected to fail as soon as the photon scattering mean free path s becomes smaller than a few wavelengths of the light. In this case, the distance between two scattering events is so short that (1) each scattered photon does not reach the far-field limit before being rescattered and (2) the (differential) scattering cross section of each and every scatterer is affected by multiply scattered photons returning to it. A first attempt to describe these near-field effects was recently proposed by Rezvani Naraghi et al. [9], but takes into account only the first point. In this paper, we propose a different light ...

Given a certain binary phase, its crystal structure can usually be rationalized by thermodynamics and packing rules. However, there is still no fundamental understanding of how metastable solids form and how this is influenced by kinetic factors. Furthermore, the very early stages of crystallization remain vague. We present an experimental study using a binary mixture of colloidal particles as a model. Particle assembly is provoked by centrifugation, and the degree of separation can be adjusted precisely. Between the scenarios of random mixture (glassy state) and complete phase separation, conditions could be realized to facilitate the occurrence of various periodic structures in a single experiment. Some of these structures can only be explained by a dynamic, nonequilibrium and dissipative state. Eventually, the formation of certain metastable lattices can be interpreted as an emergent, systemic phenomenon. Thus, centrifugation can be used for studying the chaos-order transition in complex particle systems.

Synthesis of large-area patterned MoS 2 is considered the principle base for realizing high-performance MoS 2 -based flexible electronic devices. Patterning and transferring MoS 2 films to target flexible substrates, however, require conventional multi-step photolithography patterning and transferring process, despite tremendous progress in the facilitation of practical applications. Herein, an approach to directly synthesize large-scale MoS 2 patterns that combines inkjet printing and thermal annealing is reported. An optimal precursor ink is prepared that can deposit arbitrary patterns on polyimide films. By introducing a gas atmosphere of argon/hydrogen (Ar/H 2 ), thermal treatment at 350 °C enables an in situ decomposition and crystallization in the patterned precursors and, consequently, results in the formation of MoS 2 . Without complicated processes, patterned MoS 2 is obtained directly on polymer substrate, exhibiting superior mechanical flexibility and durability (≈2% variation in resistance over 10,000 bending cycles), as well as excellent chemical stability, which is attributed to the generated continuous and thin microstructures, as well as their strong adhesion with the substrate. As a step further, this approach is employed to manufacture various flexible sensing devices that are insensitive to body motions and moisture, including temperature sensors and biopotential sensing systems for real-time, continuously monitoring skin temperature, electrocardiography, and electromyography signals.

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