Volume 3 Issue 7, July 2009

Super-resolution light microscopy methods either localize single molecular labels or treat the sample as a continuous object. The fundamental requirements for super-resolution in the continuum regime are spatially non-uniform illumination and a nonlinear photoresponse.

Multicolour, three-dimensional stochastic optical reconstruction microscopy now makes it possible to image cellular structures with near molecular-scale resolution.

Advanced imaging techniques have evolved to see beyond the diffraction limit. W. E. Moerner spoke to Nature Photonics about the techniques involved.

Resonant energy-relay between two dye species allows photovoltaic harvesting of photons across a wider spectral range. This technique has been exploited to boost the efficiency of dye-sensitized solar cells by 26%.

The demonstration of Airy beam generation and all-optical control by quasi-phase matched nonlinear crystals looks set to help these unique beams realize their exciting potential in applications.

The demonstration of lasing at 1.5 Å at the LCLS facility in the US marks an important landmark for free electron lasers.

Researchers in Japan have shown that it is possible to use standard 'off-the-shelf' plastic toy parts to construct low-cost and light-weight optical components.

Researchers from Munich and Boston have shown that multispectral photoacoustic tomography can image fluorescent proteins buried deep in highly scattering living organisms.

Diffraction of light prevents optical microscopes from having spatial resolution beyond a value comparable to the wavelength of the probing light. This essentially means that visible light cannot image nanomaterials. Here we review the mechanism for going beyond this diffraction limit and discuss how manipulation of light by means of surface plasmons propagating along the metal surface can help to achieve this. The interesting behaviour of light under the influence of plasmons not only allows superlensing, in which perfect imaging is possible through a flat thin metal film, but can also provide nano-imaging of practical samples by using a localized surface plasmon mode at the tip of a metallic nanoprobe. We also discuss the current research status and some intriguing future possibilities.

Airy beams have so far been generated by linear diffractive elements. Now, scientists show that they can also be created by a nonlinear process, opening the door to all-optical beam control and production at wavelengths unavailable by conventional methods.

Optical entanglement — a key requirement for many quantum communication protocols — is typically formed between two distinct beams, requiring repeated combination of complex resources, which becomes increasingly difficult as the number of entangled information channels increases. Here entanglement between two spatial modes within one beam is demonstrated.

Voltage-programmable liquid surface profiles with large amplitudes resulting from dielectrophoresis are demonstrated. The oil interface formed can be ultrastable and static, or rapidly switchable, as shown in the case of a modulated diffraction grating. The scheme provides the possibility for responsive and polarization-insensitive transmission and reflection devices, and for optical interfaces with arbitrary surface profiles.

The power-conversion efficiency of dye-sensitized solar cells is increased by 26% by using energy relay dyes. The scheme aids the absorption of high-energy photons that undergo Förster resonant energy transfer to a sensitizing dye, and may offer a viable pathway for developing more efficient dye-sensitized solar cells.

Opto-acoustic imaging of fluorescent proteins deep within living organisms (Drosophila melanogaster and zebrafish) is reported. The approach uses multiple wavelength illumination of the sample to generate ultrasound waves which are then detected and converted into images.

The encapsulation of LEDs, termination of optical fibres and assembly of complex lens systems are all tasks that can be accomplished by the use of special optical adhesives, explains Neil Savage.

Nature Photonics spoke to Carl Brown from Nottingham Trent University about the creation of a voltage-programmable liquid-oil surface that can rapidly switch and deflect light beams.

Optical imaging beyond the diffraction limit of light is revolutionizing sample analysis in the biological and physical sciences. In this special Focus Issue, a collection of articles are presented, detailing the fundamental physics, the different approaches and the applications where super-resolution imaging can be of help.