Volume 8 Issue 8, August 2014

Silicon photonics is the optical analogue of silicon microelectronics. It promises to use photons to detect, process and transmit information more efficiently than electrical signals, and yet have low manufacturing costs as a result of using conventional silicon-integrated-circuit processes.

Photonic crystals have long been used to confine and guide propagating electromagnetic waves with low loss. Now, a new twist has been added by exploiting their leaky mode to effectively trap and dissipate incident electromagnetic energy over a broad frequency band.

The report of an electrically pumped polariton laser that operates at room temperature and relies on an inversionless lasing scheme holds promise for realizing a new breed of very low threshold semiconductor lasers.

Marrying the single-molecule detection ability of surface-enhanced Raman scattering with the extreme time resolution of ultrafast coherent spectroscopy enables the vibrations of a single molecule to be observed.

Embedding a thin layer of chalcogenide glass inside a polymer paves the way for a new form of flexible optical waveguides and integrated optical circuits.

A breakthrough in metamaterial-based spatial light modulator design makes single-pixel real-time imaging practical by using compressive sensing to dispense with slow mechanical scanning.

An overview is given of the state-of-the-art research into secure communication based on quantum cryptography. The present security model together with its assumptions, strengths and weaknesses is discussed. Recent experimental progress and remaining challenges are surveyed as are the latest developments in quantum hacking and countermeasures.

Active metamaterials have been used to realize terahertz imaging with a single-pixel detector. Compressive techniques permit high-fidelity images to be acquired at high frame rates. The technique involves no moving parts and yields improved signal-to-noise ratios over standard raster scanning techniques.

The generation of a left-handed torque that acts in the opposite direction to light's natural spin angular momentum is reported. The effect is achieved by sending circularly polarized light into an azimuthally patterned birefringent glass disk.

To address the controversy regarding the validation of an experiment that is hard to simulate, boson-sampling experiments are implemented with three photons in randomly designed integrated chips with up to 13 modes. It is experimentally demonstrated that the Aaronson–Arkhipov test allows boson-sampling experiments to be distinguished from uniformly drawn samples.

Scalable methods employing a random unitary chip and a quantum walk chip are developed to experimentally verify correct operation for large-scale boson sampling. Experimental analysis reveals that the resulting statistics of the output of a linear interferometer fed by indistinguishable single-photon states exhibits true non-classical characteristics.

A high-resolution, broadband imaging system based on coherent anti-Stokes Raman spectroscopy performs rapid, chemically specific imaging of biological tissue. It employs three-colour excitation and operates across the entire biological window.

A photothermal imaging scheme that is analogous to optical coherence tomography can be used to construct the three-dimensional structures of bone and burn-affected skin.

A suite of flexible, integrated, high-index-contrast chalcogenide glass photonic devices, including waveguides, microdisk resonators, add–drop filters and photonic crystals, is reported. The devices are demonstrated to survive repeated bending to a submillimetre radius without any significant degradation in their optical performance.

The vibrations of the chemical bonds of a single molecule are observed by employing time-resolved coherent anti-Stokes Raman scattering. A gold nanoantenna is used to enhance the signal from the molecule.

Trapping of a terahertz wave in a photonic-crystal slab and subsequent ‘capture’ through absorption are demonstrated. Over 90% of the wave lying within 17% of the centre frequency is absorbed. Application to the stabilization of terahertz wireless communication systems is shown.

Etienne Brasselet explains to Nature Photonics that light can exert a counter-intuitive torque on matter.