Spatiotemporal imaging of nonlinear optics in van der Waals waveguides.

Van der Waals (vdW) semiconductors have emerged as promising platforms for efficient nonlinear optical conversion, including harmonic and entangled photon generation. Although major efforts are devoted to integrating vdW materials in nanoscale waveguides for miniaturization, the realization of efficient, phase-matched conversion in these platforms remains challenging. Here, to address this challenge, we report a far-field ultrafast imaging method to track the propagation of both fundamental and harmonic waves within vdW waveguides with femtosecond and sub-50 nanometre spatiotemporal precision.

Infrared nanosensors of piconewton to micronewton forces.

Mechanical force is an essential feature for many physical and biological processes, and remote measurement of mechanical signals with high sensitivity and spatial resolution is needed for diverse applications, including robotics, biophysics, energy storage and medicine. Nanoscale luminescent force sensors excel at measuring piconewton forces, whereas larger sensors have proven powerful in probing micronewton forces. However, large gaps remain in the force magnitudes that can be probed remotely from subsurface or interfacial sites, and no individual, non-invasive sensor is capable of measuring over the large dynamic range needed to understand many systems.

Aggregation pathway complexity in a simple perylene diimide.

This study characterizes the influence of self-assembly conditions on the aggregation pathway and resulting photophysical properties of one-dimensional aggregates of the simple imide-substituted perylene diimide, N, N'-didodecyl-3,4,9,10-perylenedicarboximide (ddPDI). We show that ddPDI, which has symmetric alkyl chains at the imide positions, assembles into fibers with distinct morphology, emission spectra, and temperature-dependent behavior as a function of preparation conditions. In all conditions explored, aggregates are one-dimensional; however, assembly conditions can bias formation to either J-like or H-like aggregates.

Advances in the photon avalanche luminescence of inorganic lanthanide-doped nanomaterials.

Photon avalanche (PA)-where the absorption of a single photon initiates a 'chain reaction' of additional absorption and energy transfer events within a material-is a highly nonlinear optical process that results in upconverted light emission with an exceptionally steep dependence on the illumination intensity. Over 40 years following the first demonstration of photon avalanche emission in lanthanide-doped bulk crystals, PA emission has been achieved in nanometer-scale colloidal particles. The scaling of PA to nanomaterials has resulted in significant and rapid advances, such as luminescence imaging beyond the diffraction limit of light, optical thermometry and force sensing with (sub)micron spatial resolution, and all-optical data storage and processing.

Progerin can induce DNA damage in the absence of global changes in replication or cell proliferation.

Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare genetic condition characterized by features of accelerated aging, and individuals with HGPS seldom live beyond their mid-teens. The syndrome is commonly caused by a point mutation in the LMNA gene which codes for lamin A and its splice variant lamin C, components of the nuclear lamina. The mutation causing HGPS leads to production of a truncated, farnesylated form of lamin A referred to as "progerin.