Reviews & Analysis

Solar cells take advantage of our most abundant source of energy, the Sun. A technique that improves the conversion of photons to electrons could potentially lead to a dramatic improvement in device efficiency.

Researchers at Harvard Medical School have developed a highly sensitive microscope that can image the mechanical properties of living tissues.

Defect engineering is crucial for realizing all-optical integrated circuits from self-assembled photonic crystals. A two-photon polymerization strategy paves the way towards incorporation of arbitrary defects in silicon inverse opal photonic crystals.

The regeneration of weak and distorted optical signals is vital in long-haul optical communication systems. Now scientists at Cornell University have developed an all-optical scheme that performs the task and is small enough to fit on a chip.

A re-examination of firefly bioluminescence has revealed that the efficiency of light generation in fireflies is actually less than half the widely accepted value. The study also casts doubts over the mechanism that determines the colour of the emission.

Optical coherence tomography is a powerful imaging technique. Thanks to work from the Massachusetts Institute of Technology, this technique just got faster and more powerful, with the potential to advance intricate imaging studies of the human body.

Devices emitting one photon at a time are a key component for quantum applications ranging from secure communication to more efficient computation. Recent advances in semiconductor-based single-photon devices bring such applications closer to reality.

The rapidly improved performance of LEDs based on multilayers of highly luminescent quantum dots could lead to promising applications in next-generation displays and lighting.

Textbooks suggest that heating, caused by phonon emission, is an inevitable and intrinsic by-product of light generation in a Raman laser. Now a design has emerged that reduces the phonon emission and may lead to higher efficiency and smaller devices.

Wavelength converters typically rely on inefficient nonlinear light–matter interactions or electro–optic effects. Researchers in the USA have now demonstrated a low-power and broadband all-optical wavelength shifter, which has the potential to fit on a single optical chip.

Optical tweezers enable precise, controlled and non-contact manipulation of small biological specimens. Rather than using a bulky microscope, it is now possible to create optical tweezers at the end of a fibre probe.

When tiny optical cavities are coupled together on the nanoscale, optical forces can dominate. A new proposal from researchers at the Massachusetts Institute of Technology provides a way of harnessing these forces, leading to microcavities that can mechanically adapt their geometry.

A design of laser-pumped magnetometer that combines the properties of alkali metal atoms with fabrication technology from the semiconductor industry could help realize tiny mass-producible devices with high sensitivity and low power consumption.

Researchers in London have produced a scalable microphotonic chip that can optically detect and address individual atoms. The end result could be atom–photon chips capable of complex, system-level functionality.

Solitons in optical fibres are important in the generation of supercontinuum light. An understanding of the diverse physics that is involved when intense optical pulses propagate along nonlinear fibres will enable the engineering of broad-wavelength sources for a wide range of applications.