Optical techniques

Measuring three-dimensional dielectric tensors is desired for applications in material and soft matter physics. Here, the authors use a tomographic approach and inversely solve the vectorial wave equation to directly reconstruct dielectric tensors of anisotropic structures.

A spatially resolved optical polarimetry technique is used to identify a three-state Potts-nematic order parameter in a triangular lattice antiferromagnetic material.

By exciting chiral plasmons within a nanohole by means of circularly polarized light pulses, orbital angular momentum can be imparted onto charged matter waves (here, electrons) and controlled at terahertz speed (femtosecond intervals).

The remote, non-volatile and reversible optical control of ferroic orders is challenging. Here, using laser illumination, multiple orders in epitaxial mixed-phase BiFeO₃ are manipulated deterministically using a thermally driven flexoelectric effect.

Long coherence times in a subset of states that allows for transitions in both microwave and optical range have been reported using an isotopically purified ¹⁷¹Yb³⁺:Y₂SiO₅ crystal, rendering the system suitable for quantum information applications.

Time-resolved ultrafast spectroscopy is combined with stimulated emission depletion microscopy to observe exciton migration in conjugated polymer films with nanometre and picosecond resolution.

A pump–push–probe time-resolved technique is developed to characterize the dynamics of photoexcitations at buried, disordered interfaces. Applied to organic bulk heterojunctions, the method provides insight on charge separation in photovoltaic films.

A large-area fabrication approach to achieve three-dimensional architectured metamaterials, with structural features spanning seven orders of magnitude, results in advanced mechanical properties, including high elasticity.

The dynamics of the magnetic correlations after photo-doping Sr₂IrO₄ are studied through ultrafast time-resolved resonant inelastic X-ray spectroscopy. The timescales are found to depend on the dimensionality of the correlations.

Applying an external magnetic field to cuprous oxide causes the energy spacings in the exciton spectrum to transition from a Poissonian distribution to one governed by the Gaussian unitary ensemble statistics, revealing a signature of quantum chaos.

A renally cleared, water-soluble dye emitting in the near-infrared-imaging (NIR)-II window outperforms a clinically approved NIR-I dye in the in vivo imaging of tumours and their nearby blood and lymphatic vasculatures.

The physicochemical properties of nanoparticles can sometimes prove difficult to characterize. Using plasmonic nanospectroscopy, hydride formation thermodynamics in individual Pd nanocrystals are found to be nearly size- and shape-independent.

A highly selective and efficient approach to covalently bond complementary DNA strands in solution and on surfaces on demand is shown. The approach involves the substitution of a pair of complementary bases by cinnamate-based crosslinks, which can be activated on exposure to ultraviolet light, and allows chemical patterning of flat and curved surfaces down to micrometre and potentially submicrometre resolutions.