Volume 9 Issue 6, June 2015

Charles Townes, the Nobel laureate acclaimed for his pioneering work on lasers and nonlinear optics, sadly passed away in January this year. Here I offer personal reflections of working with him as one of his graduate students.

An inverse-design approach yields ultra-compact, high-performance photonic components from patterns of complex, subwavelength voids etched into silicon.

Controlled growth of non-cubic, anisotropic solar cell materials, such as antimony selenide, is bringing new opportunities for efficient thin-film photovoltaics.

High-speed 2 μm digital optical receivers are brought closer to reality by an extended-response foundry-made monolithic silicon-on-insulator avalanche photodiode.

Kerr optical nonlinearities are known to be well suited for achieving optical isolation, but the fact that the degree of non-reciprocity is signal-level dependent brings new opportunities as well as limitations.

This Review covers recent advances in the implementation of spin–photon interfaces in semiconductor quantum dots, nitrogen–vacancy centres in diamond and emerging systems such as colour centres in other wide-bandgap materials.

An on-chip integrated wavelength demultiplexer designed using an inverse computational algorithm is experimentally demonstrated. 1,300 and 1,550 nm wavelength light is sorted in a device area of just 2.8 × 2.8 μm².

Researchers used an inverse design algorithm and experimentally demonstrated an integrated polarization beamsplitter with a footprint of 2.4 × 2.4 μm².

Researchers have synchronized XUV and VUV attosecond pulses simultaneously generated by high-harmonic generation. Such pulses with different photon energies may be useful for pump–probe experiments.

Researchers show that optical isolators based on nonlinearity cannot provide complete isolation for arbitrary backwards propagating noise, revealing limitations for their practical application.

A silicon detector that is capable of long-wavelength photodetection at multi-gigabit per second data rates could prove useful for unlocking a new wavelength window for optical communications.

An end-to-end continuous-variable quantum key distribution system with an untrusted node is proposed. A proof-of-principle experiment shows that 10⁻¹ secret key bits per relay use are distributed at 4 dB loss, corresponding to 20 km in optical fibre.

Molecular orientation in polymer solar cells is shown to play an important role in device performance.

Materials with a one-dimensional crystal structure, such as antimony selenide, show considerable potential for making efficient thin-film solar cells.