Volume 7 Issue 12, December 2013

The development of hydrogel patches that both guide light and accommodate optogenetic cells could usher in a new breed of implantable systems for in-body optical sensing and therapy.

The experimental observation of topologically protected photonic edge transport in a silicon chip paves the way to realizing unprecedented control of light using synthetic magnetic fields and opens up new approaches for optical information processing.

Efficient photocatalytic splitting of water to realize carbon-free production of hydrogen from sunlight remains a challenge. New precious-metal-free molecular catalysts in semiconductor-based, visible-light-driven water-splitting systems are promising for realizing practical artificial photosynthesis.

Metasurfaces, two-dimensional versions of metamaterials, look poised to replace their three-dimensional counterparts in many applications.

Hyperbolic, or indefinite, metamaterials are reviewed. These anisotropic materials may exhibit properties such as strong enhancement of spontaneous emission, diverging density of states, negative refraction and superlensing.

A new laser-field measurement technique is demonstrated that exploits nonlinear optical mixing in a gas in which attosecond pulses are being generated. The instantaneous field of an unknown pulse is imprinted onto the deflection of an attosecond pulse using an all-optical set-up with a bandwidth of up to 1 PHz.

Room-temperature lasing in core–shell–cap GaAs/AlGaAs/GaAs nanowires is demonstrated using optical pumping. It is realized by employing a Fabry–Pérot cavity along with material optimization and surface recombination minimization. This demonstration should prove useful for designing nanoscale optoelectronic devices operating at near-infrared wavelengths.

Two-, three- and higher multiphoton absorption processes are shown to occur in amyloid protein fibres, which are thought to play a role in various diseases, including Alzheimer's and Parkinson's diseases. The nonlinear optical behaviour of such proteins may also be useful for fabricating photonics devices.

Excitation with thermal light from a superluminescent diode is shown to yield enhanced fluorescence from both quantum dots and dyes, potentially enabling higher-sensitivity biological imaging.

A wireless communication system with a maximum data rate of 100 Gbit s⁻¹ over 20 m is demonstrated using a carrier frequency of 237.5 GHz. The photonic schemes used to generate the signal carrier and local oscillator are described, as is the fast photodetector used as a mixer for data extraction.

A continuous-variable cluster state containing more than 10,000 entangled modes is deterministically generated and fully characterized. The developed time-domain multiplexing method allows each quantum mode to be manipulated by the same optical components at different times. An efficient scheme for measurement-based quantum computation on this cluster state is presented.

Polymer hydrogel patches that are capable of supporting living cells and guiding light are used to perform in-vivo optical sensing and therapy in living mice. Tasks performed include toxicity testing and glucose regulation.

Transparent polymer solar cells are demonstrated that can transmit 30% of visible light and operate with a power conversion efficiency of 5.6%. The cells employ photonic crystals to trap ultraviolet and infrared light.

Topological edge states of light are observed in a two-dimensional array of coupled optical ring resonators, which induce a virtual magnetic field for photons using silicon-on-insulator technology. The edge states are experimentally demonstrated to be robust against intrinsic and introduced disorder, which is a hallmark of topological order.

Room-temperature, optically pumped GaAs/AlGaAs/GaAs nanowire lasers have been realized. Dhruv Saxena and Sudha Mokkapati from the Australian National University discuss this breakthrough.