Volume 10 Issue 2, February 2016

The definition and reporting of spatial resolution for coherent imaging methods varies widely in the imaging community. We advocate the use of a standard spoke-pattern imaging target and the mandatory inclusion of information about underlying a priori assumptions.

Dynamic control of magnetization by short laser pulses has recently attracted much interest. The Kerr nonlinearity has now been utilized to modulate the polarization of light at terahertz frequencies.

X-ray counterparts of visible light optical elements are notoriously difficult to realize because the refractive index of all materials is close to unity. It has now been demonstrated that curved waveguides fabricated on a silicon chip can channel and deflect X-ray beams by consecutive grazing reflections.

The quantum concepts of entanglement and interaction-free measurements are applied to spectroscopy to successfully sense carbon dioxide in air.

Concepts and advances of lead sulphide nanocrystal-based photodetector technologies are reviewed.

Single Xe clusters are superheated using an intense optical laser pulse and the structural evolution is imaged with a single X-ray pulse. Ultrafast surface softening on the nanometre scale is resolved within 100 fs at the vacuum/sample interface.

The refractive index and absorption coefficient of a medium in the infrared range are measured using visible spectral range components. The technique relies on nonlinear interference of infrared and visible photons, produced by down-conversion.

Two-photon Rabi oscillations are observed in He on a timescale of 10 fs by utilizing the strong-field phenomenon known as Freeman resonance. The importance of ponderomotive shifts of both the Rydberg states and the ionization limit is highlighted.

Hanbury Brown and Twiss measurements on speckle patterns propagating along curved surfaces improve understanding of spatial coherence.

Terbium gallium garnet is used to demonstrate a new approach to magneto-optical modulation at frequencies up to 1.1 THz.

Perovskite crystals are shown to be highly efficient materials for optical refrigeration, supporting cooling of up to 58 K when exposed to laser light.

By exploiting a second off state of a reversibly switchable fluorophore, a general approach that can reduce photobleaching and enhance resolution of coordinate-targeted fluorescence nanoscopy has been demonstrated.

An optoelectronic device that efficiently converts infrared light to visible light could prove useful for imaging applications.