Adaptive optics

Supply concerns over rare-earth elements mined in China are worrying the rest of the world.

Adaptive optics has a huge range of applications. Nadya Anscombe talks to Robert Tyson, associate professor at the University of North Carolina at Charlotte in the USA, to find out his views on its future.

Light can now be used to raise a wing-shaped refractive object, in a technique analogous to aerodynamic lift. Grover Swartzlander from the Rochester Institute of Technology in the USA told Nature Photonics how his team achieved optical lift using a uniform collimated beam of light.

Researchers report the direct observation of ultrafast magnetic dynamics using the magnetic component of highly intense terahertz wave pulses with a time resolution of 8 fs. This concept provides a universal ultrafast method of visualizing magnetic excitations in the electronic ground state.

Scientists demonstrate a fully integrated and scalable waveguide chip that can control the polarization and intensity of light using a row of independent atomic junctions. The device may enable quantum states of matter and light to be engineered on a microscopic scale.

The diffraction of light scales with wavelength, thereby placing fundamental limits on applications such as imaging, microscopy and communications. Here, researchers experimentally demonstrate scale-free propagation in supercooled structures and cancel diffraction, instead of merely compensating for it, as is the case for most approaches in nonlinear optics.

Entangled photon states, obtained by post selection, are used to perform interferometric phase measurement with a sensitivity beyond the shot-noise limit.

Scientists demonstrate an optical analogue of aerodynamic lift, in which an airfoil-shaped refractive object can be controlled through the radiation pressure induced by refracted and reflected rays of light.

Researchers demonstrate a probabilistic noiseless linear amplifier based on photon addition and subtraction. The technique enables coherent states to be amplified to the highest levels of effective gain and final-state fidelity, and could become an essential tool for applications in quantum communication and metrology.

Researchers use a nonlinear coherent imaging technique to demonstrate distant coherent coupling between excitons in quantum wells. The long-range nature of the coupling is attributed to the existence of spatially extended exciton states up to the micrometre range.

The unusual nonlinear optical properties of rapidly cooled disordered ferroelectric crystals allow beam spreading to be completely suppressed, irrespective of the beam width and intensity, offering potentially important applications in imaging and all-optical beam control.

Spin and charge terahertz excitations in solids are promising for implementing future technologies such as spintronics and quantum computation, but coherently controlling them has been a significant challenge. Researchers have now manipulated coherent spin waves in an antiferromagnet using the intense magnetic field of ultrashort terahertz pulses.

Using intricately sculpted light fields to control tiny objects is a well-understood and important technique. Now, the concept of sculpting the object rather than the light field promises to propel light–matter research in an exciting new direction.

ACTMOST, a new initiative subsidized by the European Commission, looks poised to boost microphotonic innovation in Europe.

The demonstration of live video conferencing using quantum key distribution suggests that applications exploiting secure video communication may be just around the corner.

Miniature lasers with dimensions approaching the nanoscale could provide the ultimate integrated source of bright and coherent light if losses can be overcome and electrical pumping made efficient.

When AOptix Technologies was set up in 2000 to exploit adaptive optics in laser communications systems, its future looked bright. But, as Nadya Anscombe finds out, the company has had to adapt to changes in the market and find new applications for its technology.

Microelectromechanical systems (MEMS) technology has allowed the realization of cost-effective, high-performance deformable mirrors for adaptive-optics-enhanced imaging.

The advent of ophthalmic imaging instruments equipped with adaptive optics technology now makes it possible to visualize the retina at the cellular level, allowing the early detection of eye diseases.