Laser: A two-domain photon-phonon laser.

The laser is one of the greatest inventions in history. Because of its ubiquitous applications and profound societal impact, the concept of the laser has been extended to other physical domains including phonon lasers and atom lasers. Quite often, a laser in one physical domain is pumped by energy in another.

Impact of substrates and quantum effects on exciton line shapes of 2D semiconductors at room temperature.

Exciton resonances in monolayer transition-metal dichalcogenides (TMDs) provide exceptionally strong light-matter interaction at room temperature. Their spectral line shape is critical in the design of a myriad of optoelectronic devices, ranging from solar cells to quantum information processing. However, disorder resulting from static inhomogeneities and dynamical fluctuations can significantly impact the line shape.

The propagation speed of optical speckle.

That the speed of light in vacuum is constant is a cornerstone of modern physics. However, recent experiments have shown that when the light field is confined in the transverse plane, the observed propagation speed of the light is reduced. This effect is a consequence of the transverse structure which reduces the component of wavevector of the light in the direction of propagation, thereby modifying both the phase and group velocity.

Unsupervised full-color cellular image reconstruction through disordered optical fiber.

Recent years have witnessed the tremendous development of fusing fiber-optic imaging with supervised deep learning to enable high-quality imaging of hard-to-reach areas. Nevertheless, the supervised deep learning method imposes strict constraints on fiber-optic imaging systems, where the input objects and the fiber outputs have to be collected in pairs. To unleash the full potential of fiber-optic imaging, unsupervised image reconstruction is in demand.

Morphological and chemical profiling for forensic hair examination: A review of quantitative methods.

Within the past two decades, there have been many studies for quantitative analysis on human hair samples. Microscopical and chemical analysis techniques have been used to analyze various aspects of hair regarding biological, chemical, anthropological, cosmetic, and forensic applications. Studies have attempted to develop quantification methods to increase the evidentiary value of hair in forensic casework.

Ultralight plasmonic structural color paint.

All present commercial colors are based on pigments. While such traditional pigment-based colorants offer a commercial platform for large-volume and angle insensitiveness, they are limited by their instability in atmosphere, color fading, and severe environmental toxicity. Commercial exploitation of artificial structural coloration has fallen short due to the lack of design ideas and impractical nanofabrication techniques.

Video-rate Raman-based metabolic imaging by Airy light-sheet illumination and photon-sparse detection.

Despite its massive potential, Raman imaging represents just a modest fraction of all research and clinical microscopy to date. This is due to the ultralow Raman scattering cross-sections of most biomolecules that impose low-light or photon-sparse conditions. Bioimaging under such conditions is suboptimal, as it either results in ultralow frame rates or requires increased levels of irradiance.

Reduced Cell-ECM Interactions in the EpiSC Colony Center Cause Heterogeneous Differentiation.

Mechanoregulation of cell-extracellular matrix (ECM) interactions are crucial for dictating pluripotent stem cell differentiation. However, not all pluripotent cells respond homogeneously which results in heterogeneous cell populations. When cells, such as mouse epiblast stem cells (EpiSCs), are cultured in clusters, the heterogeneity effect during differentiation is even more pronounced.

Identification and highly selective differentiation of organic gunshot residues utilizing their elemental and molecular signatures.

Firearm related evidence is of great significance to forensic science. In recent years, many researchers have focused on exploring the probative value of organic gunshot residue (OGSR) evidence, which is often bolstered by many factors including recoverability. In addition, OGSR analysis has shown the potential to achieve differentiation between OGSRs generated from various ammunition brands and/or calibers.

Quantitative phase contrast imaging with a nonlocal angle-selective metasurface.

Phase contrast microscopy has played a central role in the development of modern biology, geology, and nanotechnology. It can visualize the structure of translucent objects that remains hidden in regular optical microscopes. The optical layout of a phase contrast microscope is based on a 4 f image processing setup and has essentially remained unchanged since its invention by Zernike in the early 1930s.

An osteogenic magnesium alloy with improved corrosion resistance, antibacterial, and mechanical properties for orthopedic applications.

The aim of this study was to develop a novel biodegradable magnesium (Mg) alloy for bone implant applications. We used scandium (Sc; 2 wt %) and strontium (Sr; 2 wt %) as alloying elements due to their high biocompatibility, antibacterial efficacy, osteogenesis, and protective effects against corrosion. In the present work, we also examined the effect of a heat treatment process on the properties of the Mg-Sc-Sr alloy.

Tri-mode optical biopsy probe with fluorescence endomicroscopy, Raman spectroscopy, and time-resolved fluorescence spectroscopy.

We present an endoscopic probe that combines three distinct optical fibre technologies including: A high-resolution imaging fibre for optical endomicroscopy, a multimode fibre for time-resolved fluorescence spectroscopy, and a hollow-core fibre with multimode signal collection cores for Raman spectroscopy. The three fibers are all enclosed within a 1.2 mm diameter clinical grade catheter with a 1.

Photonic-plasmonic hot-electron-based photodetection with diffracted-order-resolved leaky plasmonic mechanisms.

Although hot-carrier-based photodetection using plasmonic effects has been widely investigated, photodetectors of this type with an external quantum efficiency (EQE) and an active area of mm remain out of reach even in the visible frequencies. In this work, a novel hot-electron-based, non-trench-type photodetector exploiting pure photoexcitation in a thin aluminum (Al) film and leaky plasmonic modes at and between its heterojunctions is proposed, analyzed, and experimentally demonstrated. Combining diffracted-order-resolved analytical analysis and numerical computations unravels the optical absorption mechanism of the innovative design.

Phase memory of optical vortex beams.

Optical vortex beams are under considerable scrutiny due to their demonstrated potential for applications ranging from quantum optics to optical communications and from material processing to particle trapping. However, upon interaction with inhomogeneous material systems, their deterministic properties are altered. The way these structured beams are affected by different levels of disturbances is critical for their uses.

Simultaneous Spatiotemporal Measurement of Structural Evolution in Dynamic Complex Media.

When the properties of soft materials evolve in time, the simultaneous measurement of different characteristics is critical. Here, we demonstrate an experimental system that permits monitoring both the spatial and temporal evolution of the optical and mechanical properties. An integrated fiber-optic-based system allows determining the mechanical vibrations of structural elements over 5 orders of magnitude and over a broad frequency range.

Thermalization Dynamics of Nonlinear Non-Hermitian Optical Lattices.

We develop a rigorous theoretical framework based on principles from statistical mechanics that allows one to predict the equilibrium response of classical non-Hermitian arrangements in the weakly nonlinear regime. In this respect, we demonstrate that a pseudo-Hermitian configuration can always be driven into thermal equilibrium when a proper nonlinear operator is paired with the linear Hamiltonian of the system. We show that, in this case, the system will thermodynamically settle into an irregular pattern that does not resemble any known statistical distribution.

Open-Form Configurational Isomers of a Tricyanofuran-Type Metastable-State Photoacid.

We determine the presence of four open-form configurational isomers for an unsubstituted metastable-state photoacid (mPAH) of the tricyanofuran (TCF) type in solution, at room temperature, via 2D NMR experiments. Electronic structure calculations are carried out to predict the relative stability of the isomers found experimentally and their isomerization barriers. According to the calculated rate constants for isomerization, the molecule can freely interconvert between the open-form isomers, thereby providing a thermal pathway between the isomers that might be better suited to access the cyclized closed-form configuration and those that are not.

New Two-Photon Absorbing Squaraine Derivative with Efficient Near-Infrared Fluorescence, Superluminescence, and High Photostability.

The nature of linear photophysical and nonlinear optical properties of a new squaraine derivative 2,4-bis[4-(azetidyl)-2-hydroxyphenyl]squaraine () with efficient near-infrared (NIR) emission was comprehensively analyzed based on spectroscopic, photochemical, and two-photon absorption (2PA) measurements, along with quantum chemical analysis. The steady-state absorption, fluorescence, and excitation anisotropy spectra of and its fluorescence emission lifetimes revealed the multiple aspects of the electronic structure of , including the relative orientations of the main transition dipoles, effective rotational volumes in solvents of different polarities, and a maximum molar extinction of 1.35 × 10 M·cm, which is unusually small for similar symmetric squaraines.

Computational Investigation of the Ordered Water System Around Microtubules: Implications for Protein Interactions.

The existence of an exclusion zone in which particles of a colloidal suspension in water are repelled from hydrophilic surfaces has been experimentally demonstrated in numerous studies, especially in the case of Nafion surfaces. Various explanations have been proposed for the origin of this phenomenon, which is not completely understood yet. In particular, the existence of a fourth phase of water has been proposed by G.