Volume 5 Issue 3, March 2011

Using a bottom-up integration approach and exploiting helical-mode resonance in a nanopillar, scientists have now demonstrated that it is possible to grow nanolasers directly on silicon substrates.

Scientists have realized a Fourier-transform spectroscopy scheme based on a wavefront-division scanning interferometer that operates down to wavelengths as short as 40 nm, benefitting studies of gas-phase atomic and molecular electronic structures over the entire vacuum-ultraviolet range.

The laser acceleration of ion beams usually relies on the use of strong electric fields generated by short, intense laser pulses. Scientists have now experimentally demonstrated that radiation pressure can also play a valuable role in this process.

Combining ultrasonic modulation and optical phase conjugation allows light to be tightly focused in a scattering medium, providing benefits for studies of photophysical, photochemical and photobiological processes.

By tailoring the electronic band structure of highly mismatched alloys, researchers have shown clear evidence of the existence of three electronically isolated energy bands, bringing the intermediate-band solar cell one step closer to realization.

Metals are widely used throughout the fields of plasmonics and metamaterials owing to their unique focusing capabilities. Research has now shown that doped, low-loss semiconductors compatible with standard nanoelectronic fabrication processes could outperform metals in certain applications.

Fourier-transform spectroscopy offers high resolution, wavelength accuracy and broad tunability, but is so far limited to the mid-ultraviolet range, down to wavelengths of 140 nm. Now, based on a wavefront-division scanning interferometer, researchers present a Fourier-transform spectroscopy scheme that covers a broad wavelength range of 40–250 nm with 7% tunability and an extrinsic absolute wavelength accuracy of 10⁻⁷.

Focusing into a scattering medium is much more valuable than focusing through it. Scientists now demonstrate the dynamic focusing of light into a scattering medium by combining the ultrasonic modulation of diffused coherent light with optical phase conjugation.

Scientists demonstrate a cavity-stabilized laser system with a reduced thermal noise floor, exhibiting a fractional frequency instability of 2 × 10⁻¹⁶. They use this system as a stable optical source in an ytterbium optical lattice clock to resolve an ultranarrow 1 Hz linewidth for the 518 THz clock transition. Consistent measurements with a clock instability of 5 × 10⁻¹⁶/√τ are reported.

Next-generation X-ray sources have allowed new opportunities for ultrafast imaging, but such schemes require femtosecond synchronization between the pump and probe laser pulses. Here, researchers present few-femtosecond timing between a free-electron laser and an external laser exploiting terahertz radiation.

Researchers exploit a dielectric planar antenna to tailor the angular emission of single photons from an oriented molecule. Record collection efficiency of 96% and detection rates of 50 MHz are demonstrated using a microscope objective at room temperature.

Based on a CMOS-compatible growth process, researchers successfully demonstrate the bottom-up integration of InGaAs nanopillar lasers onto silicon chips. The resulting nanolaser offers tiny footprints and scalability, making it particularly suited to high-density optoelectronics.

Scientists describe a size-selective quantum dot patterning technique that involves kinetically controlling the nanotransfer process without a solvent. The resulting printed quantum dot films exhibit excellent morphology and a well-ordered quantum dot structure. This technique allows fabrication of a 4-inch (or larger) thin-film transistor display with high colour purity and extremely high resolution.

The strong scattering of light in biological tissue impedes the development of light-based biological imaging. Lihong Wang explained to Nature Photonics how the use of ultrasound can aid the deeper and tighter focusing of light in scattering media.